U.S. patent application number 11/330814 was filed with the patent office on 2006-08-31 for devices with multiple surface functionality.
This patent application is currently assigned to Princeton University. Invention is credited to Michael J. Alvatroni, Ellen S. Gawalt, Jeffrey Schwartz.
Application Number | 20060194008 11/330814 |
Document ID | / |
Family ID | 46323604 |
Filed Date | 2006-08-31 |
United States Patent
Application |
20060194008 |
Kind Code |
A1 |
Schwartz; Jeffrey ; et
al. |
August 31, 2006 |
Devices with multiple surface functionality
Abstract
Phosphorus-based coatings having a plurality of phosphate
moieties, a plurality of phosphonate moieties, or both, covalently
bonded to an oxide surface of an implantable substrate exhibiting
one or more of the following characteristics: (a) the surface
phosphorus-containing group density of the coated regions of the
substrate is at least about 0.1 nmol/cm.sup.2; (b) the
phosphorus-based coating has a thickness of less than about 10 nm;
or (c) the surface phosphorus-containing group density of the
coated regions of the substrate is equal to or greater than the
surface hydroxyl group density of the oxide surface of the
substrate. Implantable devices embodying the coated substrates are
also disclosed.
Inventors: |
Schwartz; Jeffrey;
(Princeton, NJ) ; Gawalt; Ellen S.; (Pittsburgh,
PA) ; Alvatroni; Michael J.; (Staten Island,
NY) |
Correspondence
Address: |
SYNNESTVEDT LECHNER & WOODBRIDGE LLP
P O BOX 592
PRINCETON
NJ
08542-0592
US
|
Assignee: |
Princeton University
Princeton
NJ
|
Family ID: |
46323604 |
Appl. No.: |
11/330814 |
Filed: |
January 12, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10876294 |
Jun 23, 2004 |
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11330814 |
Jan 12, 2006 |
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10405557 |
Apr 1, 2003 |
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11330814 |
Jan 12, 2006 |
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10179743 |
Jun 24, 2002 |
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11330814 |
Jan 12, 2006 |
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09668080 |
Sep 22, 2000 |
6645644 |
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11330814 |
Jan 12, 2006 |
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10701591 |
Nov 4, 2003 |
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11330814 |
Jan 12, 2006 |
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60643647 |
Jan 13, 2005 |
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60643648 |
Jan 13, 2005 |
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60684159 |
May 25, 2005 |
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60699498 |
Jul 15, 2005 |
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60707525 |
Aug 12, 2005 |
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60480670 |
Jun 23, 2003 |
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60369236 |
Apr 1, 2002 |
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60369237 |
Apr 1, 2002 |
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60300144 |
Jun 22, 2001 |
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60389574 |
Jun 18, 2002 |
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60155398 |
Sep 22, 1999 |
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60490613 |
Jul 28, 2003 |
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60467348 |
May 2, 2003 |
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60446680 |
Feb 11, 2003 |
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60446681 |
Feb 11, 2003 |
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Current U.S.
Class: |
428/34.4 ;
428/632 |
Current CPC
Class: |
Y10T 428/12556 20150115;
C03C 17/001 20130101; A61L 31/086 20130101; A61P 31/00 20180101;
C23C 22/48 20130101; A61L 29/106 20130101; C23C 14/06 20130101;
C03C 17/23 20130101; B82Y 30/00 20130101; A61L 27/32 20130101; Y10T
428/12611 20150115; B82Y 40/00 20130101; C23C 22/02 20130101; B05D
1/185 20130101; Y10T 428/131 20150115; Y10T 428/265 20150115 |
Class at
Publication: |
428/034.4 ;
428/632 |
International
Class: |
B28B 11/00 20060101
B28B011/00 |
Claims
1. A phosphorus-based coating comprising a plurality of phosphate
moieties, a plurality of phosphonate moieties, or both, covalently
bonded to an oxide surface of an implantable substrate exhibiting
one or more of the following characteristics: (a) the surface
phosphorus-containing group density of the coated regions of said
substrate is at least about 0.1 nmol/cm.sup.2; (b) the
phosphorus-based coating has a thickness of less than about 10 nm;
and (c) the surface phosphorus-containing group density of the
coated regions of said substrate is equal to or greater than the
surface hydroxyl group density of the oxide surface of said
substrate.
2. The phosphorus-based coating of claim 1 wherein the surface
phosphorus-containing group density is at least about 0.5
nmol/cm.sup.2.
3. The phosphorus-based coating of claim 1, wherein the
phosphorus-based coating comprises a surface phosphorus-containing
group density of at least about 0.8 nmol/cm.sup.2.
4. A phosphorus-based coating comprising a plurality of phosphate
moieties, a plurality of phosphonate moieties, or both, covalently
bonded to an oxide surface of an implantable substrate exhibiting
one or more of the following characteristics: (a) the surface
phosphorus-containing group density of the coated regions of said
substrate is at least about 0.1 nmol/cm.sup.2; (b) the
phosphorus-based coating has a thickness of less than about 100 nm;
and (c) the surface phosphorus-containing group density of the
coated regions of said substrate is equal to or greater than the
surface hydroxyl group density of the oxide surface of said
substrate.
5. The phosphorus-based coating of claim 1 wherein the
phosphorus-based coating has a thickness of less than about 5
nm.
6. The phosphorus-based coating of claim 1 wherein the
phosphorus-based coating has a thickness of less than about 3
nm.
7. The phosphorus-based coating of claim 1 wherein the
phosphorus-based coating has a thickness of less than about 2
nm.
8. The phosphorus-based coating of claim 1, wherein the
phosphorus-based coating has a thickness of about 1.5 nm.
9. The phosphorus-based coating of claim 1, wherein the
phosphorus-based coating comprises a surface phosphorus-containing
group density of at least about 1.3 times the surface hydroxyl
group density of the oxide surface of the implantable
substrate.
10. The phosphorus-based coating of claim 1, wherein the
phosphorus-based coating comprises a surface phosphorus-containing
group density of at least about 2 times the surface hydroxyl group
density of the oxide surface of the implantable substrate.
11. The phosphorus-based coating of claim 1, wherein the
phosphorus-based coating is cell resistant.
12. The phosphorus-based coating of claim 1, wherein: the
phosphorus-based coating has a first, inner surface and a second,
outer surface, the first, inner surface being defined by the
phosphate moieties, the phosphonate moieties, or both, being bonded
to the oxide surface of the implantable substrate; and the second,
outer surface exhibiting functional groups at a position remote to
the phosphate moieties, the phosphonate moieties, or both, said
functional groups comprising hydroxyl groups, phosphonate groups,
phosphate groups, amino groups, thiol groups, carboxylate groups,
carboxylic acid groups or a combination or a derivative
thereof.
13. A phosphorus-based coating comprising a plurality of phosphate
moieties, a plurality of phosphonate moieties, or both, bonded to
an oxide surface of an implantable substrate wherein: the surface
phosphorus-containing group density of the coated regions of said
substrate is at least about 0.25 nmol/cm.sup.2; the
phosphorus-based coating comprises a surface phosphorus-containing
group density of at least about 1.3 times the surface hydroxyl
group density of the oxide surface of the implantable substrate;
and the phosphorus-based coating has a thickness of less than about
5 nm.
14. The phosphorus-based coating of claim 13, wherein: the surface
phosphorus-containing group density of the coated regions of said
substrate is at least about 0.5 nmol/cm.sup.2; the phosphorus-based
coating comprises a surface phosphorus-containing group density of
at least about 2 times the surface hydroxyl group density of the
oxide surface of the implantable substrate, and the
phosphorus-based coating has a thickness of not more than about 2
nm.
15. An implantable device comprising a phosphorus-based coating
according to claim 1.
16. The implantable device of claim 15, wherein the
phosphorus-based coating is bound to the oxide surface of the
implant to attain a shear strength of at least about 20 MPa.
17. The implantable device of claim 15, wherein the
phosphorus-based coating is bound to the oxide surface of the
implant to attain a shear strength of at least about 40 MPa.
18. The implantable device of claim 15, wherein the
phosphorus-based coating is bound to the oxide surface of the
implant to attain a shear strength of at least about 50 MPa.
19. The implantable device of claim 15, wherein the
phosphorus-based coating is bound to the oxide surface of the
implant to attain a tensile strength of at least about 60 MPa.
20. The implantable device of claim 15, wherein the
phosphorus-based coating is bound to the oxide surface of the
implant to attain a tensile strength of at least about 80 MPa.
21. The phosphorus-based coating of claim 12, wherein the second,
outer surface exhibits functional groups at a position omega to the
phosphate moieties, the phosphonate moieties, or both, said
functional groups comprising hydroxyl groups, phosphonate groups,
phosphate groups, amino groups, thiol groups, carboxylate groups or
a combination or a derivative thereof.
22. An implantable device comprising a phosphorus-based coating
according to claim 12.
23. The phosphorus-based coating of claim 13, wherein the outer
surface of the coating exhibits functional groups at a position
remote to the phosphate moieties, the phosphonate moieties, or
both, said functional groups comprising hydroxyl groups,
phosphonate groups, phosphate groups, amino groups, thiol groups,
carboxylate groups or a combination or a derivative thereof.
24. The implantable device of claim 15 selected from the group
consisting of vascular devices, artificial hearts and heart assist
devices, orthopedic devices, dental devices, drug delivery devices,
ophthalmic devices, urological devices, catheters, neurological
devices, neurostimulation devices, electrostimulation devices,
electrosensing devices and synthetic prostheses.
25. The implantable device of claim 24, wherein the vascular device
is selected from the group consisting of grafts, stents, stent
grafts, catheters, valves, artificial hearts and pacemakers.
26. The implantable device of claim 24, wherein the orthopedic
device is selected from the group consisting of a fracture repair
device and artificial tendon.
27. The implantable device of claim 24, wherein the ophthalmic
device is a glaucoma drain shunt.
28. The implantable device of claim 24, wherein the urological
device is selected from the group consisting of a penile,
sphincter, urethral, bladder devices and renal devices
29. The implantable device of claim 24, wherein the synthetic
prostheses is selected from the group consisting of breast
prostheses and artificial organs.
30. The implantable device of claim 24, wherein the device is
selected from the group consisting of dialysis tubing and
membranes, blood oxygenator tubing and membranes, blood bags,
sutures, membranes, cell culture devices, chromatographic support
materials, biosensors, anastomotic connector, surgical instruments,
angioplasty balloons, wound drains, shunts, tubing, urethral
inserts, blood oxygenator pumps, and wound tubing.
31. The implantable device of claim 24, wherein the device is
selected from the group consisting of electrical stimulation leads,
brain tissue stimulators, central nerve stimulators, peripheral
nerve stimulators, spinal cord nerve stimulators and sacral nerve
stimulators.
32. A device comprising one or more surfaces comprising a coating
of claim 1.
33. An implantable device wherein at least a portion of the oxide
surface of said device is bonded to a phosphorus-based coating
comprising a plurality of phosphate moieties, a plurality of
phosphonate moieties, or both, exhibiting one or more of the
following characteristics: (a) the surface phosphorus-containing
group density of the coated portions of said device is at least
about 0.1 nmol/cm.sup.2; (b) the phosphorus-based coating has a
thickness of less than about 100 nm; and (c) the surface
phosphorus-containing group density of the coated regions of said
substrate is equal to or greater than the surface hydroxyl group
density of the oxide surface of said substrate.
34. The implantable device of claim 33 wherein: the
phosphorus-based coating comprises a surface phosphorus-containing
group density of at least about 0.5 nmol/cm.sup.2; and the
phosphorus-based coating comprises a surface phosphorus-containing
group density of at least about 1.3 times the surface hydroxyl
group density of the oxide surface of the implantable substrate.
the phosphorus-based coating has a thickness of less than about 10
nm;
35. The implantable device of claim 15, wherein the substrate is a
metallic substrate.
36. The implantable device of claim 35, wherein the substrate is
titanium or an alloy thereof.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority to U.S. Provisional
Application No. 60/643,647 filed Jan. 13, 2005; U.S. Provisional
Application No. 60/643,648 filed Jan. 13, 2005; U.S. Application
No. 60/684,159 filed May 25, 2005; U.S. Application No. 60/699,498
filed Jul. 15, 2005; and, U.S. Application No. 60/707,525 filed
Aug. 12, 2005, the entire contents of all of which are hereby
incorporated by reference.
[0002] This application is also a continuation-in-part of U.S.
application Ser. No. 10/876,294, filed Jun. 23, 2004, which claims
priority to U.S. Provisional Application No. 60/480,670, filed Jun.
23, 2003, which in turn is a continuation-in-part of U.S.
application Ser. No. 10/405,557, filed Apr. 1, 2003, which claims
priority to U.S. Provisional Application Nos. 60/369,236 and
60/369,237, both filed Apr. 1, 2002, which in turn is a
continuation-in-part of U.S. application Ser. No. 10/179,743, filed
Jun. 24, 2002, which claims priority to U.S. Provisional
Application Nos. 60/300,144 and 60/389,574, filed Jun. 22, 2001 and
Jun. 18, 2002, which in turn is a continuation-in-part of U.S.
application Ser. No. 09/668,080, filed Sep. 22, 2000, now U.S. Pat.
No. 6,645,644, issued Nov. 11, 2003 which claims priority to U.S.
Provisional Application Ser. No, 60/155,398, filed Sep. 22,
1999.
[0003] The present application also is a continuation-in-part of
U.S. application Ser. No. 10/701,591, filed Nov. 4, 2003, which
claims priority to U.S. Provisional Application Nos. 60/490,613,
60/467,348, 60/446,680, and 60/446,681, filed Jul. 28, 2003, May 2,
2003, Feb. 11, 2003, and Feb. 11, 2003, respectively.
[0004] The disclosures of all of the above-described prior
applications are incorporated herein by reference in their entirety
for all purposes.
FIELD OF THE INVENTION
[0005] The present invention relates to the provision of a medical
device with one or more surface coatings covalently bonded to the
oxide surface of one or more regions of the device to create
different desirable surface properties on each region of the device
surface. The present invention also relates to the provision of an
adherent, self-assembled, phosphorous acid-based coating on an
oxide surface, both as a coating layer for the surface and as an
interface between the oxide surface and overlaying layers. Although
the present application is illustrated below with the provision of
orthopedic devices with multiple surface functionality derived from
surface-bonded, organic acid-based mono-layers, it will be
appreciated that the methods and devices of the present invention
provided thereby have much broader applicability.
BACKGROUND OF THE INVENTION
[0006] Implantable medical devices, whether partially or completely
implanted in the body, are frequently exposed to multiple types of
physiological environments. It is frequently desirable for a device
to exhibit different properties or biological functionality on
different regions of the device surface depending on the
physiological environment. Examples of specific functions that may
be desirable for medical implant surfaces include:
EXAMPLE 1
Cell Specific Adhesion and Attraction
[0007] It is frequently desirable to promote the adhesion of
specific cells to surfaces. For example, for orthopedic implants
and dental, it is desirable to specifically attract osteoblasts to
a surface. For devices in contact with arterial walls, such as
stents, it may be desirable to promote adhesion of specific
endothelial cells to the outer wall of the stent to promote the
arterial wall to heal and incorporate the stent.
EXAMPLE 2
Non-Adhesion
[0008] It is frequently desirable to prevent adhesion of cells,
proteins or other biomolecules to certain surfaces of medical
implants. For example, implant surfaces with long term exposure to
blood may generate thrombus. Inflammatory cells may also adhere to
and proliferate on implant surfaces leading to increased
inflammation and decreased healing rates. Adherence of thrombus and
inflammatory cells can be minimized by a non-adherent surface.
EXAMPLE 3
Anti-Corrosion
[0009] When exposed to physiological conditions, the surface of a
metal implant corrodes and leaches metal ions into the body. Some
patients exhibit heightened sensitivity or allergic response to
certain metal alloys. For example, some patients exhibit nickel
sensitivity. Metal sensitivity may lead to implant rejection and
require explantation. Other metal ions, such as chromium, may have
long term toxicity. It would be desirable to design a coated
medical device that retains its medical functionality, but that
exhibits significantly lower leaching of metal ions.
EXAMPLE 4
Anti-Infection
[0010] Infection presents a serious concern for implants. It would
be desirable to covalently attach antibiotics, anti-microbial
agents or agents that disrupt microbial pathogenesis such as
anti-quorum sensing agents to regions of an implant.
EXAMPLE 5
Anti-Inflammatory
[0011] Implantation or deployment of medical devices frequently
causes injury at the site of deployment/implantation. For example,
balloon expandable stents injure the arterial wall when deployed
resulting in inflammation that causes partial or complete
restenosis of the artery. Similarly with orthopedic implants,
trauma and inflammation from implantation results in long healing
times. It would be desirable to provide an anti-inflammatory
coating on portions of an implant.
[0012] Creating a stable bond between bone tissue and the surface
of metallic bone implants is a research topic of considerable
interest. Poor bonding with the interface between the metallic
surface of the implant and the bone tissue leads to low mechanical
strength of the bone-to-implant junction and the possibility of
subsequent implant failure.
[0013] Titanium and titanium alloys are used extensively as dental
and orthopedic implants. Currently, there is no effective way to
obtain strong attachment of incipient bone with the implant
material at the interface between the surfaces of the two materials
in order to "stabilize" the implant.
[0014] An important goal for interface optimization is to use
species which are biocompatible and which enable bone
mineralization at the interface following implantation. Bone tissue
is a combination of protein and mineral content, with the mineral
content being in the form of hydroxyapatite.
[0015] The problem of interface synthesis is often approached from
the prospective of high temperature methods, including using plasma
or laser-induced coating techniques. However, these methods
engender problems of implant heating and surface coverage. For
example, calcium phosphate deposition at high temperatures can give
rise to ion migration. Plasma-induced phosphate coating of a
titanium substrate gives surface hydroxyapatite as well as surface
calcium phosphate, titanates and zirconates. Therefore, control of
surface stoichiometry can be problematic, and defects at the
interface may translate into poor mechanical strength.
[0016] The use of intermediate layers, for example of zirconium
dioxide, to enhance hydroxyapatite adhesion and interface
mechanical strength has been explored with success. However, a
practical limitation involving laser or plasma deposition is that
it is hard to obtain comprehensive coverage on a titanium implant
of complex 3-dimensional structure. The zirconium dioxide interface
formed at high temperatures is of low surface area and maintains
few, if any, reactive functional groups for further surface
modification chemistry.
[0017] Solution-phase surface processing does not suffer from the
practical limitations of surface coverage that can be attendant
with plasma or laser-based deposition methods, and procedures
involving formation of hydroxyapatite from solution, often using
sol-gel type processing, have been accomplished. Elegant
methodologies have been developed in which graded interfaces have
been prepared, extending from the pure implant metal to the
biomaterial at the outer extremity by way of silicates. However,
while solution-based procedures are inexpensive and give rise to
materials resistant to dissolution by bodily fluids, adhesion of
the hydroxyapatite to the implant metal is less strong than is
observed when deposition is accomplished by plasma spraying
techniques.
[0018] The deficiency of these solution approaches may lie in the
nature of the native oxide surface of titanium materials. Exposure
of a clean surface of titanium materials to oxygen results in the
spontaneous formation of surface titanium oxides (native oxide).
The exact chemical stoichiometry and structure of these oxides
varies from material to material, and with depth in the oxide
layer, with environmental variables, and with the processing
history of the material. The oxide layer may be stoichiometric,
super-stoichiometric, or sub-stoichiometric with respect to
TiO.sub.2, a stable oxide of titanium. Generally, the uppermost
layer of the native oxides comprises some form of TiO.sub.2. It may
be crystalline, but if crystalline, it is generally disordered.
Typically, many different phases exist within the oxide layer
between the metal and the ambient environment. Generally, the
uppermost layer of oxide includes widely dispersed hydroxyl
functional groups bonded to a titanium atom. The surface forms
spontaneously by exposing the metal or alloy to the ambient
environment, and is alternatively described as the "native oxide
surface" of a titanium material.
[0019] As described in co-pending U.S. patent application Ser. No.
10/701,591, filed Nov. 4, 2003, Ser. No. 10/405,557, filed Apr. 1,
2003, and Ser. No. 10/179,743, filed Jun. 24, 2002, each of which
is incorporated herein by reference in their entirety, and as
described in U.S. Pat. No. 6,433,359 to Kelley et al., it is known
that a phosphorous acid can be used to provide a layer on an oxide
surface. For example, the use of phosphonic acid species on
implantable materials has been disclosed by Descouts et al. (U.S.
patent application Ser. No. 10/432,025), which is incorporated
herein by reference in its entirety. But these phosphonic acid
species fail to strongly adhere to the implant because they are not
covalently bonded via heating. In addition, Descouts does not
disclose the preparation of different surface treatments on the
same implant.
[0020] The inventors have recognized the need for the provision of
coated medical devices with different desirable surface properties
and coatings which have an improved degree of organization and/or
improved adhesion strength and/or which can be applied to surfaces
over a large area, particularly when the coating is to be applied
in a pattern.
SUMMARY OF INVENTION
[0021] In one aspect, the present invention provides a medical
device or an implantable device with one or more surface coatings
covalently bonded to an oxide surface of one or more regions of the
device to create different desirable surface properties on each
region of the device surface. The coated medical device may be
produced from an implantable substrate.
[0022] In another aspect, the present invention provides a medical
device or an implantable device comprising at least one surface to
which is covalently bonded at least one species of phosphonic acid.
The phosphonic acid may be terminated such that it may be further
derivatized to provide clinically desirable functionality or the
phosphonic acid species may itself provide the clinically desirable
functionality. Clinically desirable functionality includes cell
specific adhesion, cellular non-adhesion, osteoconduction,
anti-thrombogenicity, anti-inflammation, anti-corrosion,
anti-infection, infection prevention, wear resistance, lubrication,
and ion blocking.
[0023] In one embodiment of the invention, an implantable device is
provided wherein at least a portion of an oxide surface of the
device is covalently bonded to a phosphorus-based coating
comprising a plurality of phosphate moieties, a plurality of
phosphonate moieties, or both. The coated regions of the
implantable device can exhibit a surface phosphorus-containing
group density of at least about 0.1 nmol/cm.sup.2; can exhibit a
surface phosphorus-containing group density equal to or greater
than the surface hydroxyl group density of the oxide surface of the
implantable device; and the phosphorus-based coating can have a
thickness of less than about 10 nm.
[0024] Still another aspect of the invention relates to a
phosphorus-based coating comprising a plurality of phosphate
moieties, a plurality of phosphonate moieties, or both, covalently
bonded to an oxide surface of an implantable substrate. The coated
regions of the implantable substrate can exhibit a surface
phosphorus-containing group density of at least about 0.1
nmol/cm.sup.2; can exhibit a surface phosphorus-containing group
density equal to or greater than the surface hydroxyl group density
of the oxide surface of the implantable substrate; and the
phosphorus-based coating can have a thickness of less than about
100 nm.
[0025] In one embodiment, the surface phosphorus-containing group
density of the coated regions of the implantable substrate is at
least about 0.1 nmol/cm.sup.2; the surface phosphorus-containing
group density is equal to or greater than the surface hydroxyl
group density of the oxide surface of the implantable substrate;
and the phosphorus-based coating has a thickness of less than about
10 nm.
[0026] In another embodiment, the surface phosphorus-containing
group density of the coated regions of the implantable substrate is
at least about 0.25 nmol/cm.sup.2; the phosphorus-based coating
comprises a surface phosphorus-containing group density of at least
about 1.3 times the surface hydroxyl group density of the oxide
surface of the implantable substrate; and the phosphorus-based
coating has a thickness of less than about 5 nm.
[0027] In another embodiment, the phosphorus-based coating can have
a first, inner surface and a second, outer surface, the first,
inner surface being defined by the organophosphate moieties, the
organophosphonate moieties, or both, being bonded to the oxide
surface of the implantable substrate. Additionally or alternately,
the second, outer surface can exhibit functional groups at a
position remote to or omega to the organophosphate moieties, the
organophosphonate moieties, or both, said functional groups
comprising hydroxyl groups, phosphonate groups, phosphate groups,
amino groups, thiol groups, or a combination thereof.
[0028] In another embodiment of the invention, the phosphorus-based
coating can be bound to an oxide surface of an implantable
substrate to attain a shear strength of at least about 2 MPa, or at
least about 40 MPa or at least about 50 MPa, or at least about 60
MPa or at least about 70 MPa. Additionally, the phosphorus-based
coating can be bound to the oxidize surface of the implantable
substrate and/or a metallic implant to attain a tensile strength of
at least about 60 MPa or at least about 80 MPa.
[0029] Other features of the present invention will be pointed out
in the following description and claims, which disclose, by way of
example, the principles of the invention and the best methods which
have been presently contemplated for carrying them out.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] FIG. 1 shows IR spectra of (a) Titanium coated with
11-hydroxyundecylphosphonic acid; (b) Titanium coated with
methyl-terminated poly(ethylene glycol), pre-treatment; and (c)
Titanium coated with methyl-terminated poly(ethylene glycol),
post-treatment with the Fenton like reagent;
[0031] FIG. 2 shows IR spectra of Titanium coated with
methyl-terminated poly(ethylene glycol), (a) pre- and (b)
post-treatment with the Fenton like reagent;
[0032] FIGS. 3(a) and 3(b) show IR spectra of Titanium coated with
11-hydroxyundecylphosphonic acid, (a) pre- and (b) post-treatment
with the Fenton like reagent between FIG. 3(a) 2700-3100 wave
numbers and FIG. 3(b) 1025-1125 wave numbers;
[0033] FIGS. 4(a) and 4(b) show plots of nanomoles of supernatant
versus time, representing hydrolysis of DANSYL-RGDC from a layered
phosphonic acid film over FIG. (a) 5 hours, and FIG. (b) over 96
hours followed by hydrolysis;
[0034] FIG. 5 shows self-assembled monolayer phosphorus-containing
films derivatized to give a maleimido "tail" group, which can add
cysteine-SH or lysine-NH.sub.2 groups;
[0035] FIG. 6 shows a simple pattern formed by masking the
maleimido-derivatized SAMP and adding an aqueous solution of
dithiothreitol to it through holes in the mask;
[0036] FIG. 7 shows regions of a hip implant with different surface
properties and functionality;
[0037] FIG. 8 shows the acetabular cup with its convex surface
(Region 9a) and its convex surface (Region 9b);
[0038] FIGS. 9(a) and 9(b) show a comparison of in-vivo
osteoconductivity and bone structure at 2 weeks on an implanted
material functionalized with RGD according to the present invention
(FIG. 9(a)) and functionalized with RGD via a thiol gold linker
(FIG. 9(b));
[0039] FIG. 10 shows a plot of percent bone surface coverage of an
implant versus time at 2, 4 and 8 weeks;
[0040] FIG. 11 shows an example of a coating shear stength testing
apparatus; and
[0041] FIG. 12 shows an example of a coating tensile strength
testing apparatus.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0042] According to one aspect of the present invention there is
provided on the native oxide surface of a material a
multi-segmented, phosphorous-based coating layer having a
difunctional organo-phosphonic acid-based segment bonded to the
native oxide surface of said material and a linking segment bonded
to said organo-phosphonic acid-based segment. The present invention
thus can provide a dense-coverage, adherent, phosphorous-based
coating covalently bonded to the native oxide surface of a
substrate.
[0043] Accordingly, the present invention also provides a
phosphorous-based coating layer comprising a plurality of
.omega.-functionalized organo-phosphonate moieties bonded to the
native oxide surface of a substrate by a phosphonate bond and a
plurality of one or more coating moieties selected from the group
consisting of inorganic, organic, or bioactive moieties, each said
coating moiety being bonded to the .omega.-functional group of at
least one .omega.-functionalized organo-phosphonate moiety by means
of a member of the group comprising a metal complex and an organic
polymer, and when bonded by means of a metal complex, the metal
complex further characterized by being derived from a metal
reagent, preferably a metal alkoxide reagent, and when bonded by
means of an organic polymer, the organic polymer further
characterized by being derived from an ionic or step-reaction
polymerization which incorporates one or more of said
.omega.-functional groups into said polymer.
[0044] Preferred native oxide surfaces include, but are not limited
to, the surfaces of titanium metal and its alloys, stainless steel
and alloys, aluminum and its alloys, tantalum, silicon,
cobalt-chromium and cobalt-chromium alloys consisting of mixtures
of the elements cobalt, chromium, nickel molybdenum, and nitnol.
Nevertheless, while many of the substrate surfaces are described
herein as being titanium materials, other substrate materials may
be used in compliance with the present invention, particularly
those oxidized metals having low surface functional (e.g.,
hydroxyl) content. It is preferred for the organo-phosphonic
acid-based segment to be derived from an .omega.-functionalized
organo-phosphonic acid containing a hydrocarbon ligand having from
about 2 to about 40 carbon atoms, wherein the hydrocarbon ligand is
a linear or branched, saturated or unsaturated, substituted or
unsubstituted, aliphatic or aromatic alkylene moiety.
[0045] Titanium metal from which medical implants are made
typically has a purity such that the mass of the material is
greater than about 98 wt % titanium, for example, the ALLVAC series
of titanium metal available from Allegheny Technologies Company,
for example, ALLVAC 70, which comprises about 98 wt % titanium, and
ALLVAC 30 CP-1, which comprises 99.5 wt % titanium. Although the
present invention is applicable to bulk titanium metal, which is of
either lower or higher purity, and such material is not outside of
the scope of the present invention, in general the lower purity
material is not employed as medical implant material.
[0046] Typical titanium alloys from which medical implants are made
contain at least about 80 wt % titanium, with the remainder
comprising other metals and trace elements. Examples of titanium
alloys (titanium materials containing more than trace amounts of
other metals) which are used in the construction of medical
implants are also found in the ALLVAC series of titanium alloys
available from Allegheny Technologies Company, for example, ALLVAC
Ti-15-Mo, which contains about 15 wt % Mo and in excess of about
84% titanium, ALLVAC 6-4, which contains about 4% vanadium, about 6
wt. % aluminum, and in excess of 89 wt % titanium (which alloy is
also described herein as Ti-6Al-4V), and ALLVAC 6-2-4-Si, which
contains about 6 wt % aluminum, about 2 wt % molybdenum, about 2 wt
% tin, about 4 wt % zirconium, and in excess of 85 wt % titanium.
Other purities and specifications of titanium alloys, whether used
for the construction of medical implants or not, are known, and are
also amenable to the present invention, and are therefore also
contemplated in the term "titanium materials". It will be
appreciated that materials which can be derivatized to have an
oxide surface can also be employed.
[0047] For the application of phosphonate coatings using the
general procedures described above, the phosphorous-based acid used
is selected from the organic phosphonic acids. For purposes of the
present invention, "phosphonic acid" refers to compounds having the
formula H.sub.2RPO.sub.3, wherein R is an organic ligand with a
carbon atom directly bonded to phosphorus.
[0048] Phosphonic acid species which are useful in the formation of
coatings of the present invention may have, as the organic ligand
of the molecule, a hydrocarbon which comprises an alkylene or
arylene. Generally, useful alkylene and arylene hydrocarbon ligands
will comprise between about 2 and about 40 carbon atoms, although
the present invention contemplates organic portions outside of this
range as the properties desired of the coating formed dictate
larger or smaller organic portions.
[0049] An alkylene organic ligand of a phosphonic acid suitable for
use in the present invention may be linear or branched, saturated
or unsaturated, and unsubstituted or substituted with one or more
substituents. An arylene organic ligand may comprise direct
attachment of an aromatic moiety to the phosphorous atom of the
phosphonic group, or it may be attached by an intervening alkylene
moiety. Additionally, the arylene ligand may be incorporated into
an alkylene chain (an arylene moiety having two or more alkyl
substituents) or be a substituent depending from an alkylene chain.
Substituent from arylene moieties may additionally be unsubstituted
or may have one or more additional substituents.
[0050] Substituents on the hydrocarbon portion of phosphonic acids
useful in the present invention may be appended to any carbon atom
of the hydrocarbon ligand. Useful substituents are, for example,
reactive functional groups, for example, a hydroxyl group,
carboxylic group, an amino group, a thiol group, a phosphonate
group, and chemical derivatives thereof. It will be appreciated
that any functional group which can participate in a further
derivatization reaction can be employed. Additionally, an alkylene
hydrocarbon ligand may contain within the structure or appended to
the structure, reactive moieties, for example sites of
unsaturation, which may be further reacted in a polymerization
reaction with reactive substituents on the hydrocarbon ligands
appended to other phosphonate sites bound to the surface of the
native oxide during a phosphonate derivatizing reaction. In this
manner, a phosphonate-organo-polymeric layer may be formed on the
oxide surface. An example of such a polymerization reaction is the
preparation of a surface coating of acrylic phosphonic acid.
Unexpectedly, when acrylic acid and methacrylic acid substituents
are employed, the polymerization proceeds spontaneously upon
exposure to air. For less reactive coatings, the polymerization can
be performed by exposing the coating to conventional polymerization
reagents and conditions.
[0051] In a particularly preferred embodiment, coatings are formed
from phosphonic acids having an organic ligand functionalized at
the .omega.-carbon of the ligand which is further reacted to form
covalent bonds with chemical precursors of bone tissue protein,
such as amino acids, or with the bone tissue protein itself. For
.omega.-functionalized phosphonic acids, the application of the
acid to oxide surface generally results in a self-assembled
phosphonic acid film with the .omega.-carbon directed away from the
substrate surface and available for covalent bonding or further
chemical modification. Preferred .omega.-functional groups include
hydroxyl, amino, carboxylate, thiol, and phosphonate groups.
[0052] It will also be appreciated that the reactive substituents
pendant on the organic portion of a phosphonate bound to the oxide
surface can be further reacted with reagents which are subject to
hydrolysis reactions. Examples include metal alkoxides, examples of
which are those having the structure M-(O--R).sub.n, where M is a
metal, R is a linear or branched, saturated or unsaturated,
aliphatic or aromatic, substituted or unsubstituted hydrocarbon
moiety, and "n" is equal to a stable valance state of the metal.
Examples of metal alkoxide compounds are
zirconium-tetrakis-(t-butoxide), titanium-tetrakis-(t-butoxide),
and silicon-tetrakis-(t-butoxide) where R is a t-butyl group, M is
respectively Zr, Ti, and Si, and "n" is four. It will be
appreciated that other hydrolytically reactive compounds which have
two or more alkoxide ligands in addition to other ligands may also
be utilized. For example, calcium alkoxides, for example, calcium
bis(2-methoxy-ethoxide). In general, alkoxide ligated metals in
groups 2 through 14 will find utility in these secondary
functionalization reactions with phosphonate coatings of the
present development.
[0053] When the reactive moieties appended to the free ends of the
phosphonate coating layer are derivatized with a metal alkoxide
(this is to say, a metal alkoxide "linking" segments is added)
substituents having organic pi-electron delocalized moieties may be
appended to the linking segment by reaction with the metal.
Essentially any pi-electron delocalized compound capable of
reacting with a transition metal alkoxide to covalently bond a
ligand of the moiety to the transition metal is suitable for use
with the present invention. Particularly useful compounds are
pi-electron delocalized aromatic ring compounds. A particularly
preferred aromatic ring compound is a phenol, which has a
relatively acidic hydrogen that is readily transferred to the
transition metal alkoxide to initiate a reaction that results in
the formation of a transition metal phenolate. Five-membered
heteroaromatic ring compounds having proton-donating ring
substituents capable of reacting with the transition metal alkoxide
are also desirable because of their high degree of pi-electron
delocalization. Examples of such rings include furan, thiophene and
pyrrole.
[0054] Adherent, dense-coverage, phosphate coatings bound to the
native oxide surface of a titanium material (hereinafter, "a
coating of Ti-phosphate") may be prepared by treatment of the
surface under mild conditions with phosphoric acid according to the
procedures described herein. For purposes of the present invention,
"phosphoric acid" is defined according to its well-understood
meaning, H.sub.3PO.sub.4. In the process of the present invention,
treatment of a native oxide surface with phosphoric acid forms an
inorganic phosphate coating that is rich in free hydroxyl groups.
When the native oxide surface of a titanium material is coated with
a phosphate coating of the present development and analyzed by XRD,
two different titanium phosphate species were identified on its
surface. One component, Ti.sub.4H.sub.11(PO.sub.4).sub.9*H.sub.2O,
could be easily removed by rinsing with water, but the other,
Ti-phosphate, remained on the surface. Indeed, XRD analysis of the
rinsed foil, which had a dull purplish gray color, showed peaks
only for Ti-phosphate, which were identical to those of powdered
H.sub.2TiPO.sub.4. There is no long range order to the Ti-phosphate
coating, and profilimetry of the surface (at 5 mm/s with 5 mg
force) showed rough surfaces. The resistance of Ti-phosphate to
removal from Ti by rinsing of "peeling" with Scotch.TM. tape was
verified by XRD analysis; the change in relative intensities of XRD
peaks for Ti-phosphate on the Ti substrate were measured before and
after these tests was inconsequential. Since there is no preferred
orientation for Ti-phosphate on the Ti substrate, phosphate
group-derived hydroxyls of Ti-phosphate are likely also randomly
oriented. The hydroxyl groups of the present invention phosphate
coatings are available for further chemical modification
(derivatizing), and may be reacted with, for example,
hydrolytically reactive reagents, as described above for the
phosphonate layers having reactive substituents. As with the
phosphonate coating, further reaction of the phosphate hydroxyl
moieties results in dense coverage of the surface by the
derivatizing species. In this manner, species which would only
provide a sparse coating on the native oxide if reacted directly
can be used to provide a much denser coating on the phosphate
derivatized surface.
[0055] Aqueous phosphoric acid solutions having a concentration up
to about 3.0 M are preferred. For preparation of phosphate coatings
of the present invention, phosphoric acid solutions having a pH
more acidic than about pH 3.0 are preferred. Although these
preferred ranges are convenient for providing coatings of the
present invention, values outside of this range may be employed
when reactivity and solubility considerations permit.
[0056] The concentration of phosphoric acid required to form an
inorganic phosphate coating on an oxide surface is that
concentration of phosphoric acid effective to form a stable film on
the substrate surface without excessively dissolving the substrate.
This can readily be determined by those of ordinary skill in the
art without undue experimentation.
[0057] As with the coatings of phosphonate containing hydroxyl
substituents, the hydroxyl groups of the Ti-phosphate coatings of
the present invention can also serve as reactive sites for covalent
attachment of hydrolytically reactive reagents, for example, Zr or
Si alkoxides. It is observed, by comparison of infrared absorbance
by a characteristic feature of a surface bound moiety, that surface
loadings of these organometallics are 1-2 orders of magnitude
higher on Ti-phosphate coatings than those obtained on the native
oxide of Ti in which only about 15% of surface oxygen is derived
form hydroxyl groups.
[0058] Alkyl amines and silanes are reagents commonly used to
couple functionalized organics to a variety of hydroxylated
surfaces, and bond readily to the phosphate surfaces of the present
invention. For example, octadecyl(triethoxy)silane reacts
irreversibly with Ti-phosphate but not with the Ti native oxide
surface under comparable conditions. The phosphate surfaces of the
present invention may be further derivatized by reagents typically
used to react with hydroxylated oxide surfaces of non-titanium
materials.
[0059] As described above, the native oxide surface of titanium
materials is not amenable to profound alteration of the chemical
properties of the surface using typical derivatizing reactions. In
addition, as described above, the coverage of hydroxyl groups on a
native oxide surface of titanium materials is sparse, thus,
derivatizing reagents which react with hydroxyl groups
(hydrolytically reactive reagents) typically yield a coverage by
the derivatizing species which is too sparse to provide for a
significant change in the behavior of the surface of the material.
This is particularly problematic with respect to attempts to alter
the native oxide surface of titanium materials with these reagents
to promote adhesion when the materials are placed in contact with
bone tissue.
[0060] The phosphate or phosphonate coatings of the present
invention provide a layer which is sufficiently adherent and
provides dense-coverage of a reactive surface directly bonded to
sparsely-functionalized substrates, such as the native oxide
surface of titanium materials. Studies indicate that coverage
yielded by reacting phosphate coating hydroxyl groups of the
present invention with derivatizing reagents yield coverage of the
oxide surface that is about one to two orders of magnitude greater
than that obtainable by direct reaction of the derivatizing reagent
with the surface hydroxyl groups of the native oxide surface. These
dense-coverage, adherent phosphate or phosphonate coatings also can
promote the adhesion of bone tissue, and are amenable for further
derivatization by chemical species which further promote adhesion
of various coatings. For example, the surface can be provided with
a linking segment which includes a bioactive moiety that promotes
the adhesion and proliferation of osteoblasts. Owing to the
increase in specific surface density of reactive sites afforded by
the .omega.-functionalized phosphonic acid-based coating layer over
the density of reactive sites available on the native metal oxide
surface, increased interaction between the surface of the present
development and tissue contacted to the surface is observed.
[0061] The use of .omega.-functionalized phosphonic acid, for
example, 1,6-diphosphonohexane (a bis-phosphonic acid, with
phosphonate groups terminating either end of a 6 carbon alkyl
chain) and 1,12-diphosphonododecane (a bis-phosphonic acid with
phosphonate groups terminating either end of a 12 carbon alkyl
chain), to apply a coating adhered to the native oxide surface of a
material provides a layer which can be the basis of a segmented
coating described above. Such coatings can be formed by stepwise
reaction of the .omega.-functional group with a linking moiety, for
example, a metal alkoxide, for example the Zr, Si, Ti, and Ca
alkoxides described above, to provide a segmented coating having a
bisphosphonate segment bonded to a native oxide surface and a metal
oxide linking segment bonded to the bisphosphonate segment.
[0062] When the metal alkoxide segment contains hydrolyzable
ligands, for example, zirconium tetrakis(t-butoxide), one or more
tert-butoxide ligands remain after surface attachment. These
ligands can be hydrolyzed to provide metal hydroxyl sites, or which
can be reacted with, for example, an organic acid, providing a
bonded acid. The organic moiety thus attached can in turn be used
to attach other moieties, for example, bioactive moieties.
[0063] An example of this synthetic scheme is bonding a
difunctional acid to a metal alkoxide linking segment, for example,
attachment of maleimidobutyric acid (which contains carboxylic acid
functionality terminating one end of a four carbon chain and a
maleimide nitrogen terminating the other end). Attachment of the
maleimide functional group using this synthetic scheme proceeds
rapidly, essentially upon contact, and the maleimide functional end
can be employed to further bind bioactive proteins and peptides,
for example, those which promote the attachment of osteoblasts to
the surface, thus providing a surface which promotes bone tissue
adhesion.
[0064] An example such a surface is the surface of an implant which
has been functionalized with a peptide, for example, RGDC (the
cysteine modified fibronectin cell attachment peptide
argynine-glycine-aspartic acid). Although the reaction between the
peptide and the maleimide linking segment goes to completion, the
reaction rate for the coupling reaction is slow, taking several
days to run to completion at room temperature.
[0065] Additional examples of the peptides which can be attached
using this synthetic scheme include KRSR
(lysine-arginine-serine-arginine, which is specific for osteoblast
attachment) in the form of derivatives, for example KRSRGGE and
KRSRGGC (the glycine-glycine-glutamic acid and
glycine-glycine-cysteine modified derivatives respectively of
KRSR).
[0066] Additional examples of bioactive moieties which can be
attached to a surface using this scheme include biodegradable
polymers, for example, polylactide (--[--CH.sub.2--C(O)--O--]--),
and polyglycolic acid (--[--CH(CH.sub.3)--C(O)--O--]--).sub.n which
can be attached through strong coordinate bonds of the acid
terminal groups to the zirconium metal center in a surface layer
having a zirconium alkoxide linking segment. It is known to
incorporate bioactive molecules, for example lactam antibiotics and
growth factor-releasing hormones into such polymers. An implantable
surface containing polymers of this type would provide antibiotics
or hormones at the site of implantation which might be advantageous
in promoting healing of the surgical site about an implanted
material. It will be appreciated that these polymers can also be
used as a linking segment, the functional groups of the polymer
coordinating by hydrogen bonding to the .omega.-functional group of
the surface layer formed from an .omega.-functionalized phosphonic
acid. In this sense, the biodegradable polymers provide the linking
segment, attaching the bioactive material copolymerized with the
degradable polymer to the surface. Additional reactions which can
be carried out with an alkoxide linking segment include the
stepwise provision of layers of new materials on a surface through
sequential solution reactions. This synthetic scheme can be
illustrated by growth of a hydroxyapatite
(Ca.sub.10(PO.sub.4).sub.6(OH).sub.2) surface on the
above-described coating layer which has been provided with a
calcium alkoxide linking segment. A hydroxyapatite material can be
formed by reacting the coating layer surface alternately with
phosphoric acid (H.sub.3PO.sub.4) and then an aqueous calcium ion
source, for example, CaCl.sub.2, CaNO.sub.3. It will be understood
that there numerous other reactions are possible.
[0067] It will be appreciated that any of the
.omega.-functionalized phosphonic acid moieties described above
will provide a surface which can be reacted with numerous other
polymers and oligomers, for example, those traditionally used to
form a protective, decorative, or adhesive coating. When such
linking segments are introduced into coatings of the present
invention, it will be appreciated that adhesion to the underlying
native oxide surface will be improved. For example, when an
.omega.-hydroxy-organophosphonic acid moiety is used to form a
coating layer with a native oxide surface of a material, the free
hydroxyl ends can be reacted with, for example, an epoxy adhesive
by, for example, condensation polymerization, thereby providing in
epoxy adhesive coating which is attached to the coating layer
through a specific surface area bond density that exceeds what is
available by direct application of the epoxy adhesive to the
underlying native oxide surface. As a result, the surface area
specific bond strength between the adhesive layer and the coating
layer of the present invention exceeds the surface area specific
bond strength observed with direct application of the adhesive to
the underlying native oxide surface. It will be appreciated that
the ability of the surface of the coating layer of the present
invention to provide for increased surface area specific reaction
sites will improve the adhesion of numerous other coating
materials, for example, acrylate polymer coating.
[0068] The phosphate coatings of the present invention are rich in
free hydroxyl groups. The phosphonate coatings can be made to have
hydroxyl groups by using precursor acids having hydroxyl group
substituents. Each of these coating layers may be further
functionalized to promote covalent attachment to bone tissue
proteins, or precursors thereof, for example, by using thiol
compounds of the type conventionally employed to promote adhesion
between gold metal implants and bone tissue. The hydrocarbon
ligands of the organopolyphosphonate coatings may likewise be
functionalized at a substituent on the organic ligand portion as
described above for phosphonate ligand coatings to form covalent
bonds with chemical precursors of bone tissue protein or with the
bone tissue protein itself.
[0069] The coatings of the present invention can be applied to
essentially any implant intended for bone or dental tissue contact
fabricated from a material having an oxide surface at the intended
bone or dental tissue interface. Implants made of titanium and
alloys thereof may be employed, as well as implants which are made
of materials that can be provided with an adherent titanium or
other material oxide surface. Additionally, the phosphorous-based
coatings of the present invention may be applied to oxide surfaces
of materials other than titanium-materials, for example, stainless
steel and alloys, tantalum, cobalt-chromium and cobalt-chromium
alloys consisting of mixtures of the elements cobalt, chromium,
nickel, molybdenum, and nitnol and provide similar potential for
bone and coating adhesion.
[0070] The methodology of the present invention enables strong
adhesion between a dental or osteopathic implant and incipient bone
tissue via a network of strong chemical bonds. An implant device
can be fabricated and its surface processed ex-situ to provide a
composite coating on the implant surfaces that will give rise to a
strong, non-fracturable bone-to-implant seal following
implantation. The methodology is amenable to vapor-phase or
solution-phase (aerosol spray-on or "dip coating") chemistry and
proceeds under mild conditions, especially compared to plasma or
laser-induced deposition. Adhesion of the phosphorous-based surface
coating has been found to exceed 40 MPa of shear stress and 80 MPa
of tensile stress.
[0071] More complex species, for example, a protein or peptide, may
also be bonded via the derivatized surface of the present invention
to the underlying native oxide surface of an implant. For example,
bonding the fibronectin cell attachment peptide
arginine-glycine-aspartic acid (RGD), for example, in its RGDC
derivative form, to a surface through an organic tether is thought
to enhance the osteoconductivity of the surface by providing sites
for cell attachment and spreading. As described above, conventional
methods for such providing surface peptide attachment to implant
materials, such as Ti, Ti alloys, stainless steel, cobalt-chromium
and its alloys, are often problematic and only low yields of such
attachment are possible. Using the surface bonded coating of the
present development, for example, a carboxylate-functionalized
phosphonate coating, a cysteine-modified fibronectin cell
attachment peptide (RGDC), which is commercially available
(American Peptide), affords the possibility of attachment of the
peptide to a reactive site on a surface of the present invention
via formation of a thiol-ether bond using the surface coating of
the present invention treated with traditional organic
derivatization reaction techniques. It will be appreciated that
other derivatization reactions are also possible.
[0072] Examples of additional peptides which may be attached
include those which show specificity for cell attachment, for
example KRSR (lysine-arginine-serine-arginine). These peptides can
be modified without affecting their specificity for osteoblast
attachment, for example, by attaching GGE
(glycerine-glycine-glutamic acid) or GGC (glycine-glycine-cysteine)
sequences to improve attachment to the surface, thus KRSRGGE and
KRSRGGC respectively.
[0073] Another aspect of the present invention is a process for the
provision of an adherent, phosphorous-based coating layer having a
difunctional organo-phosphonic acid-based segment bonded to the
native oxide surface of said material and a coating bonded to said
organo-phosphonic acid-based segment, the process comprising: (i)
providing a native oxide surface bearing an .omega.-functionalized
organo-phosphonic acid moiety bonded thereto; (ii) and bonding said
.omega.-functional groups thereof, or derivatives of the functional
groups thereof, with a bioactive, organic, or inorganic moiety
comprising the coating. Preferred .omega.-functional groups are
hydroxyl-, carboxylate-, amino-, thiol-, and phosphonato-functional
groups, or these groups further derivatized by reaction with a
metal or organo-metal reagent, for example an alkoxide. These
groups participate in further bonding with moieties comprising the
organic, inorganic, or bioactive coating layer, either through
strong chemical bonding, for example, covalent bonding, or through
weaker bonding interactions, for example, hydrogen bonding.
[0074] Preferred metal reagents for derivatizing .omega.-functional
groups are, for example metal alkoxides, for example zirconium
tetrakis(t-butoxide), silicon tetrakis(t-butoxide), titanium
tetrakis(t-butoxide), and calcium bis(2-methoxy-ethoxide).
[0075] A preferred method of attaching a bioactive species to a
native oxide surface comprises providing a phosphorous-based
coating layer as described above wherein said
.omega.-functionalized organo-phosphonate moieties are an
alkyl-bisphosphonate which has been derivatized with a metal
alkoxide, and further reacted with an organic moiety, said organic
moiety comprising a peptide bonded by a thiol-ether bond to a
malimido-carboxylic acid group, said reaction providing a
carboxylate bond to said metal alkoxide derivatized
.omega.-functional group.
[0076] Additionally, organic moieties that may be added to the
.omega.-functional group of a phosphonic acid-based layer which
comprise oligomers or polymers, for example, adhesive polymers, for
example epoxides, polymers which form surface coatings, for example
acrylates, and oligomers, for example, those which have bioactive
properties or which can be used to attach compounds or precursors
to compounds having bioactive properties, for example, a
poly(lactide-co-glycolide) which has antibiotic activity.
[0077] Inorganic coating layers which may be bonded include, for
example, hydroxyapatite.
[0078] The present invention thus includes the methods by which the
coated substrates of the present invention are formed. Therefore,
in accordance with another embodiment of the present invention
there is provided a method of bonding a layer of a
phosphorous-based acid moiety to a sparsely-functionalized (e.g.,
titanium) oxide surface comprising coating said oxide surface with
a phosphorous-based acid moiety self-assembled layer and heating
said coated oxide surface until said self-assembled layer is bonded
thereto, the phosphorous-based acid moiety comprising the
self-assembled layer being selected from the group consisting of
phosphoric acid and organophosphonic acids.
[0079] Preferred coatings are those which have been formed from
alkylene- and arylene-organophosphonic acids, including substituted
alkylene and arylene phosphonic acids. More preferred are
substituted alkylene phosphonic acids with a reactive substituent
omega to the phosphonic acid functional group. In some embodiments,
preferred oxide surfaces include, but are not limited to, the
native oxide surfaces of titanium materials. It is preferred for
the phosphonic acid to be in the form of an aqueous solution having
a pH more acidic than about pH 3.0.
[0080] In some embodiments the adherent, multi-segmented,
phosphorous-based coating layers of the present invention promote
interaction between the coated substrate and the environment in
which the coated substrate is placed by using the coating layer to
improve the interaction of the two. An example of this is using a
coating layer of the present invention to promote the adhesion of
bone tissue to a titanium substrate on which a coating of the
present invention is placed. In other embodiments, a segment of the
adherent, multisegmented, phosphorous-based coating layer comprises
a moiety which has surface active properties, and thus itself
interacts with another surface. An example of this is the increase
in adhesive force observed between an adhesive and a titanium
native oxide surface when the adhesive is included as a linking
moiety in the coating layer of the present invention.
[0081] The methods of the present invention provide an adherent,
phosphorous acid-based coating layer bonded to an oxide surface of
a material. These coating layers have utility in derivatizing the
oxide surface to alter the properties of the surface. For example,
the chemical properties of the surface, for example, the affinity
of the surface for hydrophilic or lipophilic substances may be
altered in this manner. In addition, the electrical properties, for
example, the ability of the surface to carry out charge carrier
injection processes can be altered in this manner. While the
methods and coating layer of the present invention have broad
utility in providing a chemically derivatized coating layer on
oxide surfaces, it is anticipated that the present invention will
be most useful in the provision of phosphorous acid-based coatings
which act as interface between the oxide surface and overlayer
adhered thereto, thereby improving or facilitating the adherence of
said overlayer to the oxide surface. Examples of such uses include
improvement in the adhesion of an adhesive for a metal oxide
surface, for example, an epoxy adhesive layer bonded to the native
oxide surface of a titanium alloy, and the provision of an
osteoadhesive layer in a medical implant in living bone tissue.
Although the method of the present invention has broad
applicability in providing a phosphorous acid-based adherent
coating layer to an oxide surface, it is anticipated that the
method of the present invention will be most useful in the
provision of an adherent phosphorous acid-based coating layer on
the oxide surface of metals, semi-conductors, and insulators.
Examples of oxide surfaces include, but are not limited to, oxide
surfaces which form spontaneously (native oxides) as well as those
applied to a surface, for example by sputtering. In particular, it
is anticipated that the method will find greatest utility in the
provision of a phosphorous-based coating layer on oxides of
traditionally low reactivity, for example, the native oxide surface
of titanium alloys. Finally, although the method and coating layer
of the present invention has broad applicability in providing an
adherent phosphorous acid-based coating layer on oxide surfaces on
a wide scale of sizes, it is anticipated that the present invention
will find its greatest utility in the provision of coating layers
in operations wherein coating is done in a continuous operation,
for example, by lamination of a carrier furnished with a
phosphorous acid and a carrier of material comprising the oxide
surface to which the coating layer is applied.
Methods
[0082] Without wanting to be bound by or to any particular theory,
as described in co-pending U.S. patent application Ser. No.
10/701,591, filed Nov. 4, 2003; Ser. No. 10/405,557, filed Apr. 1,
2003; and Ser. No. 10/179,743, filed Jun. 24, 2002, each of which
is incorporated herein by reference in their entirety, it is
believed that when a phosphorous acid is contacted to an oxide
surface for a sufficient period of time under suitable temperature
conditions, there is formed a bond between the acid functional
group and the oxide surface. Surprisingly, the inventors have
discovered that adherent phosphorous coating layers can be prepared
utilizing a carrier to convey a coating composition comprising one
or more phosphorous acids to the oxide surface to be coated.
[0083] Without being bound by or to any particular theory, it is
believed that by selecting the hydrophilic properties of the
carrier to be compatible with the phosphorous acid used to provide
the coating the method of the present invention provides a coating
layer with improved order and improved bonding of multi-layer
character over methods utilizing "dip" coating, as described for
example in the aforementioned co-pending U.S. patent application
Ser. No. 10/179,743. This improvement in layer organization and
bonding provides improved coverage of the surface, improved
adhesion of the coating layer, and increases the chemical and
electronic communication between the coating layer and the
surface.
[0084] In addition, the method of the present invention is believed
to provide improvement in the efficiency of applying a coating of
the invention to a large surface area in comparison to dip-on or
paint-on methods. It will be appreciated that the method of the
present invention is readily adaptable to a continuous coating
operation using a web or belt system to provide a coating of the
invention to a continuous supply of oxide surface. The method of
the present invention also provides a convenient method of placing
a coating on an oxide surface in a pattern which has here-to-fore
only been possible by masking portions of the surface to be coated
prior to providing the coating. Accordingly the method of the
present invention provides for a reduction in the unit operations
necessary required to prepare a patterned phosphorous acid-based
coating layer on an oxide surface.
[0085] The method of the present invention comprises contacting a
carrier conveying a coating composition comprising a phosphorous
acid to an oxide surface for a sufficient duration and under
temperature conditions sufficient to form bonds between at least a
portion of the furnished phosphorous acid and the contacted oxide
surface. No particular environmental conditions are required to
provide a coating layer on an oxide surface by the present
invention method, although if it is desired the present invention
can be carried out within environmental chambers or under inert
atmospheres.
[0086] It will be appreciated that the carrier may be in many
different forms, for example, a roller, pad, sheet, roll, web, or
belt. Other forms will be apparent. It will also be appreciated
that the method of contacting the carrier to the oxide surface will
vary depending upon the phosphorous acid(s) comprising the coating
solution, the concentration, the temperature conditions, and the
nature and character of the oxide surface to be coated.
[0087] In keeping with the principles set forth herein, examples of
the various methods which may be used to contact the carrier to the
oxide surface include fashioning the carrier into a roller which is
rolled across the oxide surface, fashioning it into a stamp or
plate which is contacted to the oxide surface either manually or by
mechanical means, furnishing a roll of the carrier with the coating
solution which is unrolled onto the oxide surface, laminating a web
or belt of carrier material which has been furnished with the
coating solution to a supply of the oxide surface. It will be
appreciated that when the oxide surface permits it to be presented
as a web, belt, or sheet, for example, acrylic and poly(ethylene
terephthalate) (PET) which has been coated with silicon dioxide, a
continuous lamination process can be used. It will also be
appreciated that when the oxide surface is in a more or less rigid
form, for example, an indium tin oxide coating on glass, a feeding
mechanism accompanying a belt, chain, or web-feed type of
lamination equipment can be adapted to laminate sections of the
oxide surface with a continuous belt or web of the carrier. It will
be appreciated that many other modifications exist in the coating,
printing and laminating arts which can be adapted to contact both
flexible and rigid carrier materials with oxide surfaces residing
on either flexible or rigid substrates.
[0088] The duration of the contact between the carrier and the
oxide surface will depend upon the coating solution selected, the
oxide surface, and the temperature conditions obtaining during
contact. For example, for some oxide surfaces, for example, the
native metal oxide on aluminum, and for some acids, for example,
hydroxyundecylphosphonic acid, the coating layer will form
spontaneously at any ambient temperatures, for example about
20.degree. C., and above. Typically, for short contact times, for
example, about 5 minutes or less, contact is made under temperature
conditions of from at least about 100.degree. C. up to about
200.degree. C. If lower temperatures are employed, or for different
oxide surfaces and phosphorous acids, longer contact times, for
example several hours, may be required. One of ordinary skill can
easily determine the duration of contact required at a particular
temperature to form a satisfactory coating by placing a coupon of
carrier which has been furnished with the intended coating solution
in contact with a coupon containing a sample of the oxide surface
to be coated into an oven maintaining the intended contact
temperature for varying times and measuring the amount of
phosphorous acid-based coating formed on the oxide surface. Other
methods of determining the minimum necessary contact time at a
particular temperature for a particular coating solution and oxide
surface will be apparent.
[0089] Typically, contact times employed in the method of the
present invention are typically from about 1 minute to about 20
minutes at temperatures from ambient, e.g., about 20.degree. C., to
about 200.degree. C. More preferably, contact times from about 5
minutes to about 20 minutes are employed at temperatures from about
50.degree. C. to about 200.degree. C.
[0090] It will be appreciated that when heating is required to
drive the coating reaction, numerous arrangements may be employed
to provide the heat to the contacted carrier and oxide surface.
These include, but are not limited to, applying a heated body to
the distal side of the carrier while the proximal side of the
carrier is in contact with the oxide surface, contacting the
carrier and oxide surface within a heated zone, for example, within
an oven, and contacting the carrier and oxide surface and
transporting them in contact into a heated zone. In the latter
example, the oxide surface and carrier can be in the form of a
sheet which is transported through an oven or furnace on a belt or
in a batch conveyance. Alternatively, the oxide surface and carrier
can be in the form of a two webs which are contacted and passed in
contact through a heated zone, as for example, will be familiar to
those of skill in the laminating arts. In another non-limiting
example, heat to drive the coating reaction can be provided by
heating the oxide surface separately and bringing the carrier into
contact with the heated oxide surface thereafter.
[0091] The process of conveying the coating composition to the
oxide surface requires furnishing the coating composition to the
carrier. This can be accomplished by contacting the carrier with a
coating solution, removing the carrier from contact with the
coating solution, and contacting the carrier with the oxide
surface. The coating solution comprises the phosphorous acid to be
used in forming the coating and a solvent, for example, an alcohol.
In some preferred processes, between the step of removing the
carrier from contact with the coating solution and the step of
contacting the carrier conveying the coating to the oxide surface,
an evaporation step is conducted during which a portion, preferably
a substantial portion, of the solvent conveyed by the carrier from
the coating solution is evaporated. In some preferred embodiments,
after the drying step the carrier appears to be "dry" when visually
inspected, and can be handled, transported, and packaged without
exuding any solvent. In some embodiments the carrier provided with
the coating composition in this manner will be employed to provide
a coating on an oxide surface remote in time and/or location from
the time and place in which the coating composition was provided to
the carrier. It will be appreciated that other methods of providing
the coating composition to the carrier can be employed.
[0092] The present invention further provides a method of
constructing a medical device with multiple surface functionality,
comprising the steps of 1) bonding an adherent, self-assembled
phosphorous-based coating to the native oxide surface of an
implantable device; 2) masking the regions of the device not to be
reacted; 3) allowing unmasked regions of the device to react with
additional reagents to achieve a desired property for the unmasked
region; and 4) removing the masks. In Step 1, the coating layer may
be formed as a self-assembled monolayer according to the method
described in U.S. patent application Ser. No. 10/701,591. In
addition, if more than one region receives a second coating,
additional mask steps are necessary.
[0093] Without wanting to be bound by or to any particular theory,
it is thought that the evaporation step improves the organization
of the coating composition on the carrier prior to contacting the
carrier to the oxide surface.
Carriers
[0094] As indicated above, the carrier of the present invention can
comprise numerous flexible and rigid materials. In general the
carrier is selected to have some affinity, for example, hydrogen
bonding or Van der Waals interaction, for the phosphorous acid(s)
comprising the coating solution, but not to react with them.
Without being bound by or to any particular theory, it is believed
that in selecting the carrier to exhibit an affinity for the
phosphorous acid(s) comprising the coating solution the carrier
imposes some order on the acid moieties therein prior to contacting
the surface, and thereby presents the phosphorous acid from which
the coating is derived to the oxide surface as a collection of
moieties having at least short range ordering, and thereby
providing a coating layer which has imparted to it at least
localized ordering of the coating moieties. Again without wanting
to be bound by or to any particular theory, it is believed that
this is similar to the organizational effect in amphiphilic films
at an air/water interface.
[0095] Accordingly in some embodiments, preferred carriers are
those which have non-reactive surface hydroxyl groups with which
the phosphorous acid(s) comprising the coating solution can form
hydrogen bonding. Examples of this include cellulose materials, for
example, cotton fiber. Guided by these general principles it will
be apparent that materials having surfaces which have been
derivatized to have greater or lesser hydrophilic nature can also
be employed. It will be appreciated that this includes surfaces
comprising materials which, for example, fibers have regions
comprising various alcohol, ether, ester, amino, amido and like
moieties. It will also be appreciated that this includes both
materials in which this type of functionality is either naturally
occurring or in which the functionality has been introduced by
chemical derivatization of the materials. An example of one such
naturally occurring material is cotton fiber and materials made
therefrom. It will be appreciated that numerous surface
modifications of numerous materials are possible to bond moieties
containing functional groups which can "fine tune" the hydrophilic
nature of the surface to maximize the organizational effect of the
carrier for a particular coating solution.
[0096] It is contemplated that suitable carriers for the present
method include those which have absorbent properties for the
coating solution, adsorbent properties for the coating solution, or
both. Thus, the carrier material can have, for example, the form of
a reticulated or porous material which provides interstices into
which a coating solution can be take up by absorption. The carrier
can also be non-porous, utilizing adsorptive properties, for
example, a material which has an affinity for the coating solution
such that it is readily "wetted" by the coating solution. Suitable
carrier materials will generally have a mixture of both types of
properties. Thus, it will be appreciated that for some
applications, a non-porous, smooth carrier will be employed which
relies on adsorption of the phosphorous acid comprising the coating
solution to convey it to the oxide surface to be coated. In other
applications, the carrier will be porous or reticulate and have
absorptive properties for the coating solution.
[0097] Preferred carriers include cellulose materials having a
hydrophilic surface, for example woven and non-woven cotton and
woven and non-woven polymers which have hydrophilic surfaces. Rigid
materials having hydrophilic materials which are non-reactive
toward phosphorous acids are also preferred. It will be appreciated
that surfaces which have been derivatized with a phosphorous acid
which contains hydrophilic functional groups may also be
employed.
Coating Solutions and Compositions
[0098] As the term is used herein, the coating composition
comprises the acid used in forming the coating layer of the
invention organized on the carrier, some amount of the solvent
retained from the coating solution, and optionally other
constituents which may be added to improve the stability or
handling characteristics of the coating solution, as are known in
the art.
[0099] In general, coating compositions suitable for use in the
present invention method comprise an acid selected from the group
consisting of phosphoric, organophosphoric, and phosphonic acids
and a solvent. In some preferred embodiments the solvent is water
or an alcohol. Particularly preferred are phosphonic acids and
alcohol solvents, particularly ethanol. In general, coating
compositions employ dilute solutions of the acid, typically in the
millimolar (mM) concentration range. In some embodiments the
coating compositions are prepared from solutions having an acid
concentration of from about 0.01 mM to about 5.0 mM, more
preferably from about 0.1 mM to about 3.0 mM. However, in
accordance with known principles and the chemical stability of the
carrier materials and oxide surface used in the process the
concentration of the solution may be adjusted to higher or lower
values.
Acids
[0100] As used herein, the phrase "phosphorous acid" refers to
phosphoric acid (H.sub.3PO.sub.4), organophosphoric
(R.sup.1--O--PO.sub.3H.sub.2), wherein R.sup.1 is an organic moiety
bonded to the phosphorous atom through an oxygen atom, and
phosphonic acid compounds having the formula R--PO.sub.3H.sub.2,
wherein R is an organic ligand, that is, wherein a carbon atom is
directly bonded to phosphorus. In general, the organic moiety in
organo-phosphoric acids can be selected from the same organic
moieties described below for the phosphonic acid organic ligand,
guided by general chemical principles regarding the stability of
the phosphate/phosphonate species after bonding to an oxide
surface. Any of the acid species which are disclosed for preparing
coatings in any of co-pending U.S. patent application Ser. No.
10/701,591, filed Nov. 4, 2003; Ser. No. 10/405,557, filed Apr. 1,
2003; and Ser. No. 10/179,743, filed Jun. 24, 2002, each of which
is incorporated herein by reference in their entirety, may be
employed in the methods of the present invention to prepare the
coatings of the present invention.
[0101] The preferred acids for use in the present invention are
phosphonic acids. Preferred phosphonic acids have an organic ligand
selected from the group of organic moieties consisting of aliphatic
and aromatic hydrocarbon moieties having from about 2 to about 40
carbon atoms, and more preferably from about 2 to about 20 carbon
atoms. However, the present invention contemplates organic moieties
having an amount of carbon atoms lying outside of this range as the
properties desired of the coating formed dictate larger or smaller
organic moieties.
[0102] Suitable aliphatic organic moieties may be linear or
branched, saturated or unsaturated, and may be optionally
substituted with one or more functional groups, including aromatic
substituents. Aromatic organic moieties may comprise arene
structures, for example a monomeric, oligiomeric, or polymeric
arene structure, for example anthracene and pentacene, which are
directly bonded to a phosphate moiety. Alternatively, aromatic
moieties may be bonded to a phosphate moiety through an intervening
aliphatic moiety. Aromatic moieties may optionally be substituted
on any carbon with one or more functional groups.
[0103] In some preferred embodiments the ligands are selected from
organic moieties which are based on organic compounds having
electron donor and acceptor properties, for example, moieties which
are based on derivatives of the art recognized electron acceptor
and donor molecules tetracyanoquinodimethane (hereinafter "TCNQ"),
tetrathiofulvalene (hereinafter "TTF"), and
quarterthiophene-phosponate (hereinafter "4TP") the structures of
which are well known. As is known, TCNQ, TTF and 4TP are typically
used as building blocks in the provision of organic conductors. As
described in detail in co-pending U.S. patent application Ser. No.
10/701,591, filed Nov. 4, 2003, which is incorporated herein by
reference, substituted molecular derivatives of TCNQ with altered
electron acceptor properties are also known and have been
described, for example, by Yamashita et al., J. Mater. Chem., 8(9),
1933-1944 (1998), which is incorporated herein in its entirety by
reference. Moieties based on these TCNQ derivatives are also
preferred as ligands in phosphorous acids employed in coating
solutions for the present development.
[0104] Known also, and described in detail in co-pending U.S.
patent application Ser. No. 10/701,591, filed Nov. 4, 2003, which
is incorporated herein by reference, are TTF derivative compounds
with altered electron donating properties. Such molecules have been
described, for example, by Hasegawa et al., Synth. Met., 86,
1801-02 (1997), which is incorporated herein in its entirety also
by reference. As has been described, TTF can be substituted, with
electron donating groups to enhance its electron-donor properties.
Moieties based on these TTF derivatives are also preferred as
ligands for phosphorous acids used in coating solutions for the
present invention.
[0105] Substituents on the hydrocarbon ligand of phosphonic acids
useful in the present invention may be appended to any carbon atom
of the hydrocarbon ligand. Useful substituents are, for example,
those which may influence the hydrophilicity and/or lipophilicity
of a coating prepared therefrom, for example, alkyl groups, and
reactive functional groups, for example hydroxyl, carboxylic acid,
amino, thiol, sulfonic acid, phosphonic acid, and chemical
derivatives thereof. It will be appreciated that any functional
group which can participate in a further derivatization reaction
can be employed. Additionally, suitable hydrocarbon ligands may
contain within their structure or appended to their structure,
reactive moieties, for example sites of unsaturation, which may be
further reacted in a polymerization reaction with reactive
substituents on the hydrocarbon ligands appended to other
phosphonate sites bound to the surface of the oxide during a
phosphonate derivatizing reaction. Additionally, reactive
functional groups may be included on one or more carbon atoms of
the organic ligand of the acid used to form the coating. These
functional groups may be employed to further derivatize the coating
layer formed, as explained in detail below and in each of
co-pending U.S. patent application Ser. No. 10/701,591, filed Nov.
4, 2003; Ser. No. 10/405,557, filed Apr. 1, 2003; and Ser. No.
10/179,743, filed Jun. 24, 2002, each of which is incorporated
herein by reference in their entirety.
[0106] In a particularly preferred embodiment, coatings are formed
from phosphonic acids having an organic ligand functionalized at
the .omega.-carbon of the ligand. In general, when
.omega.-functionalized phosphonic acids are used to form the
coating layers of the invention, after reaction of the acid to
oxide surface resultant phosphonic acid film generally comprises
phosphonate moieties bonded to the oxide surface with the
.omega.-carbon directed away from the surface and available for
covalent bonding or further chemical modification. Preferred
.omega.-functional groups include hydroxyl, amino, carboxylate, and
thiol groups.
[0107] Another class of substituents which may advantageously be
bonded to a phosphonic acid organic ligand is pi-electron
delocalized moieties. Particularly useful compounds are pi-electron
delocalized aromatic ring compounds (oligo- and poly-arene
ligands). Five-membered heteroaromatic ring compounds having
phosphonic acid ring substituents are also desirable because of
their high degree of pi-electron delocalization. Examples of such
rings include furan, thiophene and pyrrole.
Oxidized Surfaces
[0108] As explained in detail in each of co-pending U.S. patent
application Ser. No. 10/701,591, filed Nov. 4, 2003; Ser. No.
10/405,557, filed Apr. 1, 2003; and Ser. No. 10/179,743, filed Jun.
24, 2002, each of which is incorporated herein by reference in
their entirety, a coating layer comprising a phosphorous acid in
accordance with the present invention can be formed on both native
oxide surfaces and oxide surfaces which are deposited on a
substrate or formed on an existing oxide surface. Accordingly,
non-limiting examples of native oxide surfaces upon which a
phosphorous acid-based film can be formed include materials which
have metallic, conducting, semiconducting, and insulating
properties, as those terms are defined, for example, by A. West,
Basic Solid State Chemistry, second edition, John Wiley & Sons,
New York, pp. 110-120, which is incorporated herein in its entirety
by reference. Examples of substrates suitable for use in the
process of the invention include, but are not limited to materials
which possess a native oxide surface, that is, they comprise an
oxide or form a native oxide upon exposure to the ambient
environment. Non-limiting examples of oxide materials include bulk
metal oxides, for example silica and alumina, oxides deposited on a
substrate, for example, conducting oxides, for example, indium
doped tin oxide and zinc/indium doped tin oxide each deposited on a
glass substrate, and oxide insulators, for example, low dielectric
constant glass in gate insulator material of integrated circuits
and metal oxide deposited on plastic substrates, for example
"stacked" metal oxide on PET plastic (which has a top layer of
silicon dioxide), for example anti reflective plastic obtained
commercially from Bekaert Specialty Films. Though in one embodiment
oxide surfaces are preferred surfaces, it is believed that other
oxidized surfaces may be useful as well, e.g., nitrides,
oxynitrides, carbides, oxycarbides, sulfides, oxysulfides, or the
like. Also, it is believed that the present invention can be formed
on the surface of bullk oxides.
[0109] Non-limiting examples of materials which form oxidized
surfaces upon exposure to the ambient environment (oxygen) include
steels, including stainless steels, iron, and metals which acquire
a non-ablating oxide coating upon exposure to the ambient
environment, for example, titanium, titanium alloys, aluminum,
aluminum alloys, tantalum, cobalt-chromium and cobalt-chromium
alloys consisting of mixtures of the elements cobalt, chromium,
nickel and molybdenum. Additional examples of materials which
acquire a native oxide layer upon exposure to the ambient
environment are ceramic materials, for example, silicon nitride and
semiconductors, for example silicon. Also suitable for application
of a coating of the present invention are materials which have an
oxide coating imparted to them intentionally, for example, thick
film oxide insulators in semiconducting devices, and those which
can be derivatized to have an oxidized surface, for example,
gallium arsenide, gallium nitride, and silicon carbide. Also
suitable for use in the provision of a coating layer of the present
invention are naked surfaces which can undergo hydrolysis and which
have an adsorption affinity for phosphonic acid functional groups,
for example, silicon nitride.
[0110] Particularly preferred substrates are those which are useful
in preparing electronic devices and those useful for mechanical
devices for contact with biological tissue or fluids. An example of
those useful for the preparation of electronic devices are thick
oxide insulating layers on gate junctions for use in bio-electronic
sensors which are suitable for in vivo and in vitro diagnosis and
monitoring of conditions. An additional example is indium tin oxide
conducting oxide deposited on glass. An example of a surface useful
in the preparation of mechanical devices is an implantable
material, for example, a titanium reinforcing member useful for in
vivo implant in the repair of bone tissue.
[0111] As mentioned above, suitable surfaces include the surfaces
of semiconductor substrates, for example silicon single crystal
surfaces. They include also the surfaces of polycrystalline
substrates, for example, metals, for example titanium and its
alloys, aluminum and its alloys, and silicon. Also included are the
surfaces of amorphous substrates, for example, the surface of an
oxide conductor or oxide insulator. Examples of conductive oxides
include Fe.sub.3O.sub.4, tin oxide doped to conduction, e.g., with
indium and/or zinc, zinc oxide doped to conduction, e.g., with
aluminum, zinc oxide, and sub-stoichiometric oxides, for example,
of titanium and/or vanadium.
[0112] Also preferred are ceramic substrates, for example, silicon
nitride and silicon carbide, and semiconductors, for example,
germanium and semiconducting germanium-based compounds.
[0113] In general, an oxide surface is prepared prior to contact
with the carrier by cleaning the surface to remove residual metals
and organics, generally by an oxidation treatment followed by a
water rinse. Oxide surfaces that are stable toward such treatment,
for example, a single crystal or polycrystalline silicon wafer
surface, the surface may be treated with the standard hydrogen
peroxide/sulfuric acid "piranha" solution followed by a water rinse
and a second treatment with a standard hydrogen
peroxide/hydrochloric acid "buzzard" solution, in the manner
typically followed for cleaning silicon wafers prior to fabricating
integrated circuits on the wafer. In general, the process of the
invention affords best results on oxide surfaces which are devoid
of free base species, base (zero-valent) metals, and residual
hydrocarbon species. However, even for surfaces which do not lend
themselves to a rigorous cleaning to semiconductor standards, for
example, conducting oxides, the process of the invention will still
provide a coating layer which has good adhesion to the oxide
surface upon which the coating layer is formed. Other cleaning
methods applicable to particular surfaces for the removal of the
unwanted species typical of those surfaces will be apparent to
those of skill in the art.
Derivatizing the Phosphate-/Phosphonate-Based Coating Layer
[0114] As described above and in explained in detail in each of
co-pending U.S. patent application Ser. No. 10/701,591, filed Nov.
4, 2003; Ser. No. 10/405,557, filed Apr. 1, 2003; and Ser. No.
10/179,743, filed Jun. 24, 2002, each of which is incorporated
herein by reference in its entirety, when a phosphorous acid-based
coating layer of the invention is prepared from a coating
composition comprising a reactive or functionalized surface (e.g.,
a di- or polyfunctional phosphorous acid, such as an
.omega.-functionalized phosphonic acid), the coating layer formed
can be further derivatized with additional reagents. Non-limiting
examples of such reagents include derivatizing the omega hydroxyl
groups of a coating layer formed from an .omega.-hydroxy phosphonic
acid with a protein coupling reagent and incorporating the hydroxyl
groups of such a coating layer into an epoxy adhesive layer applied
on top of the coating layer. Examples of protein coupling reagents
include maleimido and succinimidyl coupling reagents. As described
in the above-mentioned co-pending applications, and as will be
appreciated, guided by the requirements for the coating layer and
general chemical principals, numerous other derivatizing reactions
can be carried out that utilize the reactive species available in
the coating layer prepared using a phosphorous acids which includes
one or more reactive substituents.
[0115] Such reactions can be employed to provide a pattern of the
derivatized species on the surface of a coating layer provided by
the present invention. For example, the above-described protein
coupling reagent incorporated into a printing medium can be applied
in a pattern to a coating layer prepared by the process of the
invention utilizing a printing technique. Non-limiting examples of
this include providing the coupling reagent in a medium suitable
for delivery from an ink-jet printing device. When such patterns of
derivatizing reagents are applied they can find utility in
biosensor devices and in providing engineered biological structures
for example, which can be utilized in implantable devices. It will
be appreciated that other non-impact and impact printing
techniques, for example, lithography, screen printing, stamping,
and gravure printing can be adapted to provide patterns of
derivatizing reagents on coating layers of the invention.
Patterning Oxide Surfaces
[0116] In accordance with the above described principles and
methods, the coating process of the present invention can be used
to provide a coating layer which is in a pattern on the oxide
surface. Thus, a coating composition can be provided to the carrier
in a pattern which will be transferred to the oxide surface when
the carrier is contacted to an oxide surface under temperature
conditions suitable to form a bond between the oxide surface and
the coating composition. It will be appreciated that numerous means
can be used to provide a pattern of coating composition on the
carrier. Non-limiting examples include spraying a coating solution
onto the carrier in only pre-determined areas, for example, by
ink-jet printing and stencilling. Other methods may be found by
adapting printing techniques, including stamping, lithographing,
and gravure printing a coating solution onto the carrier in a
pattern.
[0117] In the same manner, the carrier itself can be provided in
the form of a pattern, for example, a stencil or a stamp. In this
manner, when a coating composition is conveyed to an oxide surface
the pattern of the carrier will transfer the coating composition to
an oxide surface in a like pattern.
[0118] It will also be appreciated that when the carrier conveying
a coating composition is in a form suitable for mechanical
manipulation, e.g., in the form of a roller or ball, it can be
mechanically directed in a pattern across an oxide surface to
provide a coating layer having a pattern reflecting the path along
which it was directed on the surface.
[0119] There follow many examples, e.g., one utilizing a carrier
comprising a cotton pad to apply a coating of the present invention
to the native oxide surface of a titanium coupon and to an oxide
surface comprising silicon dioxide deposited on a flexible plastic
sheet. The following examples are intended to illustrate the
process of the invention and the films formed thereby and are not
meant to limit the scope of the invention. It will be appreciated
that there are many modifications possible to the materials and
process steps exemplified below which still fall within the scope
of the inventive process and films.
Active Agents for Derivatized/Functionalized Surfaces
[0120] When desired, an active agent (or a combination of active
agents) can be bound to the derivatized surface according to the
invention in order to accomplish any of a variety of goals. The
particular active agent(s) used, as well as the mechanism to
chemically and/or physically attach the active agent(s) to the
derivatized surface, will obviously depend upon the chemical and/or
physical nature of the derivatization of the surface, e.g., its
reactivity, its functionality, its surface roughness, etc.
Nevertheless, the following list of active agents that are suitable
for surface immobilization according to the invention is merely
exemplary and should not be construed as being complete.
[0121] In one embodiment, the active agent can include
antileukotrienes or leukotriene receptor antagonists (e.g., for B4,
C4, D4, and/or E4 leukotriene receptors) including, but not limited
to, zafirlukast, montelukast, praniukast, iralukast, pobilukast, or
the like, or sombinations thereof, and/or salts thereof (e.g.,
Montelukast sodium, which is commercially available under the
tradename SINGULAIR.RTM.).
[0122] In another embodiment, the active agent can include
antihistamines including, but not limited to, ethanolamines (e.g.,
diphenhydramine and/or salts including hydrochloride,
dimenhydrinate, carbinoxamine, clemastine and/or salts such as
fumarate, bromodiphenhydramine and/or salts such as hydrochloride,
phenytoloxamine, doxylamine, or the like, or other salts thereof,
or combinations thereof, ethylenediamines (e.g., tripelennamine
and/or salts such as hydrochloride, pyrilamine and/or salts such as
maleate, antazoline and/or salts such as phosphate, methapyriline,
or the like, or other salts thereof, or combinations thereof,
alkylamines (e.g., chlorpheniramine and/or salts such as maleate,
brompheniramine and/or salts such as maleate, dexchlorpheniramine
and/or salts such as maleate, dimethindene and/or salts such as
maleate, triprolidine and/or salts such as hydrochloride,
pheniramine and/or salts such as maleate, or the like, or other
salts thereof, or combinations thereof, piperzines (e.g., cyclizine
and/or salts such as hydrochloride and/or lactate, meclizine and/or
salts such as hydrochloride, hydroxyzine and/or salts such as
hydrochloride and/or pamoate, buclizine, chlorcyclizine, or the
like, or other salts thereof, or combinations thereof,
phenothiazines (e.g., promethazine and/or salts such as
hydrochloride, propiomazine, methdilazine, trimeprazine and/or
salts such as tartrate, or the like, or other salts thereof, or
combinations thereof), and/or miscellaneous others (e.g.,
cyproheptadine, ketotifen, azatadine and/or salts such as maleate,
terfenadine, fexofenadine, astemizole, diphenylpyraline,
phenindamine, or the like, or salts thereof, or combinations
thereof.
[0123] In another embodiment, the active agent can include
antiseptics including, but not limited to, iodine, chlorhexidine
acetate, sodium hypochlorite, and calcium hydroxide.
[0124] In another embodiment, the active agent can include
steroidal anti-inflammatory agents including, but not limited to,
betamethasone, triamcinolone, dexamethasone, prednisone,
mometasone, fluticasone, beclomethasone, flunisolide, budesonide,
or the like, or salts thereof, or combinations thereof. In another
embodiment, the active agent can include non-steroidal
anti-inflammatory agents including, but not limited to, fenoprofen,
flurbiprofen, ibuprofen, ketoprofen, naproxen, oxaprozin,
diclofenac, etodolac, indomethacin, ketorolac, nabumetone,
sulindac, tolmetin, meclofenamate, mefenamic acid, piroxicam,
suprofen, or the like, or salts thereof, or combinations
thereof.
[0125] In another embodiment, the active agent can include
decongestants including, but not limited to, ephedrine,
phenylpropanolamine, pseudoephedrine, phenylephrine, epinephrine,
ephedrine, desoxyephedrine, naphazoline, oxymetazoline,
tetrahydrozoline, xylometazoline, propylhexedrine, or the like, or
salts thereof, or combinations thereof.
[0126] In another embodiment, the active agent can include
mucolytics including, but not limited to, acetylcysteine, dornase
alpha, or the like, or salts thereof, or combinations thereof.
[0127] In another embodiment, the active agent can include
anticholinergics including, but not limited to, ipratropium,
atropine, scopolamine, or the like, or salts thereof, or
combinations thereof.
[0128] In another embodiment, the active agent can include
non-antibiotic antimicrobials including, but not limited to,
taurolidine or the like.
[0129] In another embodiment, the active agent can include mast
cell stabilizers including, but not limited to, cromolyn,
nedocromil, ketotifen, salts thereof (e.g., sodium), or
combinations thereof.
[0130] In another embodiment, the active agent can include one or
more active ingredients such as anti-infective agents,
anti-inflammatory agents, mucolytic agents, antihistamines,
antileukotrienes, decongestants, anticholinergics, antifungals, and
combinations of these classes of agents. Anti-infective agents
contemplated by the present invention include, but are not limited
to antibiotics, anti-virals, non-antibiotic antimicrobials, and
antiseptics. Anti-inflammatory agents contemplated by the present
invention include, but are not limited to steroidal and
non-steroidal anti-inflammatory agents, and mast cell inhibitors.
Antifungal agents contemplated by the present invention include,
but are not limited to amphotericin B, and azole antifungals.
Examples of contemplated antibiotics include, but are not limited
to cefuroxime, ciprofloxacin, tobramycin, cefoperazone,
erythromycin, and gentamycin. Exemplary medications and doses that
may be used in the methods according to the present invention are
listed in Table 1. TABLE-US-00001 TABLE 1 Active agents and dosages
Alternate Alternate Brand Exemplary Exemplary Exemplary Generic
Name Name Class Range Range Range Acetylcysteine Mucomist
Mucolytics 125-500 mg 150-450 mg 200-400 mg Mucosil Amikacin Amikin
Aminoglycoside 50-500 mg 75-300 mg 100-200 mg Amphotericin B
Fungizone Antifungal 2.5-45 mg 4-30 mg 7.5-15 mg Atropine
Anticolinergic 10-700 mcg 25-400 mcg 75-300 mcg Azelastine Astelin
Antihistamine 137-1096 mcg 204-822 mcg 382-616 mcg Azithromycin
Zithromax Macrolide 50-400 mg 75-300 mg 150-200 mg Aztreonam
Azactam Monobactam 250-1000 mg 300-900 mg 475-750 mg Beclamethasone
Vanceril Steroidal Anti- 0.1-4 mg 0.2-3 mg 0.2-2 mg Beclovent
inflammatory Betamethasone Celestone Steroidal Anti- 0.1-4 mg 0.2-3
mg 0.2-2 mg inflammatory Cefazolin Ancef, Cephlasporin 250-1000 mg
300-900 mg 575-700 mg Kefzol (Gen I) Cefepime Maxipime Cephlasporin
125-1000 mg 200-900 mg 575-700 mg (Gen IV) Cefonicid Moniacid
Cephlasporin 250-1000 mg 300-900 mg 575-700 mg (Gen II)
Cefoperazone Cefobid Cephlasporin 250-1000 mg 300-900 mg 575-700 mg
(Gen III) Cefotaxime Claforan Cephlasporin 250-1000 mg 300-900 mg
575-700 mg (Gen III) Cefotetan Cefotan Cephlasporin 250-1000 mg
300-900 mg 575-700 mg (Cephamycin) Cefoxitin Mefoxin Cephlasporin
250-1000 mg 300-900 mg 575-700 mg (Cephamycin) Ceftazidime Fortaz,
Cephlasporin 250-1000 mg 300-900 mg 475-750 mg Ceptaz (Gen III)
Ceftizoxime Cefizox Cephlasporin 250-1000 mg 300-900 mg 575-700 mg
(Gen III) Ceftriaxone Rocephin Cephlasporin 250-1000 mg 300-900 mg
575-700 mg (Gen III) Cefuroxime Ceftin Cephlasporin 100-600 mg
200-520 mg 250-400 mg (Gen II) Cephapirin Cefadyl Cephlasporin
250-1000 mg 300-900 mg 575-700 mg (Gen I) Ciprofloxacin Cipro
Quinolone 25-200 mg 50-175 mg 75-110 mg Clindamycin Cleocin
Lincosamide 50-600 mg 75-500 mg 125-300 mg Cromolyn Sodium Intal/
Mast cell 5-100 mg 7.5-75 mg 10-50 mg Nasalcrom stabilizer
Dexamethasone Decadron Steroidal Anti- 0.1-4 mg 0.2-3 mg 0.2-2 mg
inflammatory Dornase alpha Pulmozyme Mucolytic 0.5-5 mg 1-4 mg 2-3
mg Doxycycline Vibramycin Tetracycline 10-100 mg 15-80 mg 25-65 mg
Erythromycin Erythrocin Macrolide 50-600 mg 60-350 mg 100-300 mg
Lactobionate Fluconazole Diflucan Antifungal 12.5-150 mg 20-70 mg
25-50 mg Flunisolide Aerobid Steroidal Anti- 0.1-4 mg 0.2-3 mg
0.2-2 mg Nasalide inflammatory Flurbiprofen Ocufen Nonsteroidal
0.01-2 mg 0.05-1 mg 0.1-0.5 mg Anti- inflammatory Fluticasone
Flonase Steroidal Anti- 10-700 mcg 25-400 mcg 75-300 mcg
inflammatory Gentamycin Garamycin Aminoglycoside 10-200 mg 30-150
mg 80-120 mg Ibuprofen Motrin Nonsteroidal 25-400 mg 30-300 mg
50-150 mg Anti- inflammatory Ipratropium Atrovent Anticholinergic
10-700 mcg 25-400 mcg 75-300 mcg Itraconazole Sporanox Antifungal
12.5-150 mg 20-70 mg 25-50 mg Ketorolac Acular Nonsteroidal 0.05-4
mg 0.1-2 mg 0.3-1 mg Anti- inflammatory Levofloxacin Levaquin
Quinolone 40-200 mg 50-150 mg 60-80 mg Linezolid Zyvox
Miscellaneous 50-600 mg 75-450 mg 100-300 mg anti-bacterial
Loratidine Claritin Antihistamine 0.5-10 mg 1-7.5 mg 1-5 mg
Meropenem Merrin Carbapenem 200-750 mg 250-700 mg 300-500 mg
Mezlocillin Mezlin Penicillin 300-1500 mg 375-1000 mg 750-950 mg
Miconazole Monistat Antifungal 12.5-300 mg 30-200 mg 50-100 mg
Montelukast Singulair Antileukotriene 0.5-15 mg 2-25 mg 3-15 mg
Mupirocin Bactroban Antibacterial 1-25 mg 1.5-20 mg 2-15 mg
Nafcillin Unipen Penicillin 250-1000 mg 300-900 mg 575-700 mg
Nedocromil Tilade Mast cell 1-25 mg 3-15 mg 5-12 mg stabilizer
Ofloxacin Floxin Quinolone 25-200 mg 50-175 mg 75-110 mg Oxacillin
Prostaphlin Penicillin 250-1000 mg 300-900 mg 575-700 mg
Oxymetazoline Afrin Decongestant 0.05-0.5 mg 0.075-0.4 mg 0.1-0.3
mg Phenylepherine Neo- Decongestant 5-50 mg 10-35 mg 15-20 mg
Synephrine Piperacillin Pipracil Penicillin 100-1000 mg 125-750 mg
250-600 mg Potassium Iodide -- Antiseptic 30-200 mg 40-150 mg 50-80
mg Rifampin Rifadin Miscellaneous 500-5000 mg 1000-4000 mg
1500-3500 mg Taurolin Taurolidine Non antibiotic 5-200 mg 20-150 mg
40-120 mg antimicrobial Tetrahydrozolidine Tizine Decongestant
0.05-0.5 mg 0.06-0.4 mg 0.1-0.3 mg Ticarcillin + Timentin
Penicillin 500-5000 mg 1000-4000 mg 1500-3500 mg Clavulanate
Tobramycin Nebcin Aminoglycoside 10-200 mg 30-150 mg 80-120 mg
Triamcinalone Asthmacor Steroidal Anti- 0.05-3 mg 0.2-2.5 mg 0.5-2
mg Aristocort inflammatory Vancomycin Vancocin Antibiotic- 50-400
mg 75-325 mg 125-250 mg miscellaneous Xylometazoline Otrivin
Decongestant 0.05-0.4 mg 0.075-0.3 mg 0.1-0.2 mg Zafirlukast
Accolate Antileukotriene 2-60 mg 4-50 mg 6-30 mg
[0131] Exemplary anti-infective agents include, but are not limited
to, penicillins, cephalosporins, macrolides, ketolides,
sulfonamides, quinolones, aminoglycosides, beta lactam antibiotics,
and linezolid. Exemplary non-antibiotic antimicrobials include
taurolidine. Exemplary steroidal anti-inflammatory agents include
glucocorticoids. Exemplary nonsteroidal anti-inflammatory agents
include diclofenac. Exemplary mast cell stabilizers include
cromolyn and nedcromil sodium. Exemplary mucolytic agents are
acetylcysteine and dornase alpha. Exemplary decongestants are
phenylephrine, naphazoline, oxymetazoline, tetrahydrozoline and
xylometoazoline. Exemplary antihistamines include loratidine.
Exemplary antibiotic combinations include cefuroxime and
gentamicin. Exemplary anticholinergics include ipratropium,
atropine and scopolamine. Exemplary antifungals include
amphotericin B, itraconazole, fluconazole, and miconazole.
[0132] In another embodiment, the active agent can include, but are
not limited to, anti-inflammatory agents (e.g., alclometasone,
amcinonide, amlexanox, balsalazide, betamethasone, celecoxib,
choline magnesium, trisalicylate, choline salicylate, chlobetasol,
colchicine, cortisone acetate, curcumin, disunite, dexamethasone,
diclofenac, diflunisal, etodolac, fenoprofen, fluocinolone,
fluometholone, flurandrenolide, flurandrenolide, flurbiprofen,
hydrocortisone, ibuprofen, indomethacin, ketoprofen, ketorolac,
meclofenamate, mefenamic acid, meloxicam, mesalamine,
Methylprednisolone, nabumetone, naproxen, olsalazine, oxaprozin,
piroxicam, prednisone, rofecoxib, salsalate, sulfasalazine,
sulindac, tolmetin, triamcinolone, valdecoxiband,
analogs/derivatives thereof, salts thereof, or combinations
thereof), immunosuppressants (e.g., azathioprine, basiliximab,
cyclosporine, daclizumab, leflunomide, lymphocyte immune globulin,
methotrexate, muromonab-CD3, mycophenolate, sirolimus, tacrolimus,
thalidomideand, analogs/derivatives thereof, salts thereof, or
combinations thereof), anti-cell proliferation agents (e.g.,
alkylating agents such as busulfan, cisplatin, cyclophosphamide,
oxaliplatin, or the like; nitrosourea compounds such as in
carmustine, lomustine, or the like; anthracycline compounds such as
epirubicin, mitoxantrone, or the like; anti-androgen compounds such
as bicalutamide, flutamide, nilutamide, or the like; antibiotics
such as bleomycin, dactinomycin, mitomycin, or the like;
anti-metabolite compounds such as cladribine, flurouracil,
gemcitabine, hydroxyurea, methotrexate, or the like;
anti-microtubular compounds such as docetaxel, paclitaxel, or the
like; aromatase inactivators such as anastrozole, exemestane, or
the like; hormones such as estramumustine, megestrol, or the like;
monoclonal antibody compounds such as alemtuzumab, rituximab, or
the like; protein synthesis inhibitors such as asparaginase,
pegaspargase, or the like; other compounds such as carboplatin,
dipyridamole, doxorubin, doxorubicin, etoposide, imatinib,
misonidazole, mercaptopurine, testolactone, trimetrexate,
glucuronate, tiripazamine, topotecan, vindesine, vincristine,
analogs/derivatives thereof, salts thereof, or combinations
thereof, anti-thromosis, anti-platelet, and/or fibrinolysis agents
(e.g., abcimab, antithrombin III, argatroban, aspirin, clopidogrel,
dipyridamole, eptifibatide, fondaparinux, heparin, low molecular
weight heparin, recombinant hirudin such as bivalirudin, lepirudin,
or the like, ticlopidine, tissue recombinant plasminogen activators
such as alteplase, reteplase, streptokinase, tenecteplase,
urokinase, or the like, tirofibanand, analogs/derivatives thereof,
salts thereof, or combinations thereof), extracellular matrix
mediators (e.g., calprotectin, catechins, sulfonylated amino acid
hydroxamates, tetracycline compounds such as demeclocycline,
doxycycline, minocycline, oxytetracycline, tetracycline, or the
like, analogs or derivatives thereof, salts thereof, or
combinations thereof), and the like, and combinations thereof.
[0133] In another embodiment, the active agent can include, but are
not limited to, anti-thrombotic agents such as heparin, heparin
derivatives, urokinase, PPack (dextrophenylalanine proline arginine
chloromethylketone), or the like, analogs/derivatives thereof,
salts thereof, or combinations thereof; steroidal and non-steroidal
anti-inflammatory agents (NSAIDs) such as dexamethasone,
prednisolone, corticosterone, hydrocortisone and budesonide
estrogen, sulfasalazine and mesalamine, salicylic acid,
salicylates, ibuprofen, naproxen, sulindac, diclofenac, piroxicam,
ketoprofen, diflunisal, nabumetone, etodolac, oxaprozin,
indomethacin, or the like, analogs/derivatives thereof, salts
thereof, or combinations thereof; anti-neoplastic or
anti-proliferative or anti-mitotic agents such as paclitaxel,
5-fluorouracil, cisplatin, vinblastine, vincristine, epothilones,
endostatin, angiostatin, doxorubicin, methotrexate, angiopeptin or
the like, analogs/derivatives thereof, salts thereof, or
combinations thereof, monoclonal antibodies capable of blocking
smooth muscle cell proliferation, thymidine kinase inhibitors, or
the like, analogs/derivatives thereof, salts thereof, or
combinations thereof; anesthetic agents such as lidocaine,
bupivacaine, ropivacaine, or the like, analogs/derivatives thereof,
salts thereof, or combinations thereof; anti-coagulants such as
D-Phe-Pro-Arg chloromethyl ketone, an RGD peptide-containing
compound, heparin, hirudin, antithrombin compounds, platelet
receptor antagonists, antithrombin antibodies, anti-platelet
receptor antibodies, aspirin, prostaglandin inhibitors, platelet
inhibitors, tick antiplatelet peptides, or the like,
analogs/derivatives thereof, salts thereof, or combinations
thereof; vascular cell growth promoters such as growth factors,
transcriptional activators, translational promoters, or the like,
analogs/derivatives thereof, salts thereof, or combinations
thereof; vascular cell growth inhibitors such as growth factor
inhibitors, growth factor receptor antagonists, transcriptional
repressors, translational repressors, replication inhibitors,
inhibitory antibodies, antibodies directed against growth factors,
bifunctional molecules consisting of a growth factor and a
cytotoxin, bifunctional molecules consisting of an antibody and a
cytotoxin, or the like, analogs/derivatives thereof, salts thereof,
or combinations thereof; protein kinase and tyrosine kinase
inhibitors such as tyrphostins, genistein, quinoxalines, or the
like, analogs/derivatives thereof, salts thereof, or combinations
thereof; prostacyclin analogs; cholesterol-lowering agents;
angiopoietins; antimicrobial agents such as triclosan,
cephalosporins, .beta.-lactams, aminoglycosides, nitrofurantoin, or
the like, analogs/derivatives thereof, salts thereof, or
combinations thereof; cytotoxic agents; cytostatic agents; cell
proliferation affectors; vasodilating agents; agents that interfere
with endogenous vascoactive mechanisms; analogs/derivatives
thereof; salts thereof; metabolites thereof; or combinations
thereof.
[0134] Exemplary genetic active agents include, but are not limited
to, anti-sense DNA and RNA as well as DNA coding for: (a)
anti-sense RNA, (b) tRNA or rRNA to replace defective or deficient
endogenous molecules, (c) angiogenic factors including growth
factors such as acidic and basic fibroblast growth factors,
vascular endothelial growth factor, epidermal growth factor,
transforming growth factor .alpha. and .beta., platelet-derived
endothelial growth factor, platelet-derived growth factor, tumor
necrosis factor .alpha., hepatocyte growth factor and insulin-like
growth factor, (d) cell cycle inhibitors including CD inhibitors,
and (e) thymidine kinase ("TK") and other agents useful for
interfering with cell proliferation. Also of interest is DNA
encoding for the family of bone morphogenic proteins ("BMP's"),
including BMP-2, BMP-3, BMP4, BMP-5, BMP-6 (Vgr-1), BMP-7 (OP-1),
BMP-8, BMP-9, BMP-10, BMP-11, BMP-12, BMP-13, BMP-14, BMP-15, and
BMP-16. Such molecules include any of the "hedgehog" proteins, or
the DNA's encoding them.
[0135] Vectors of interest for delivery of genetic active agents
include, but are not limited to, (a) plasmids, (b) viral vectors
such as adenovirus, adeno-associated virus, lentivirus, or the
like, and (c) non-viral vectors such as lipids, liposomes, cationic
lipids, or the like.
[0136] Cells include cells of human origin (autologous or
allogenic), including stem cells, or from an animal source
(xenogenic), which can be genetically engineered if desired to
deliver proteins of interest.
[0137] Non-limiting examples of useful antimicrobial agents
include: Antiamebics, e.g., Arsthinol, Bialamicol, Carbarsone,
Cephaeline, Chlorbetamide, Chloroquine, Chlorphenoxamide,
Chlortetracycline, Dehydroemetine, Dibromopropamidine, Diloxanide,
Diphetarsone, Emetine, Fumagillin, Glaucarubin, Glycobiarsol,
8-Hydroxy-7-iodo-5-quinoline-sulfonic Acid, lodochlorhydroxyquin,
lodoquinol, Paromomycin, Phanquinone, Polybenzarsol, Propamidine,
Quinfamide, Scenidazole, Sulfarside, Teclozan, Tetracycline,
Thiocarbamizine, Thiocarbarsone, Tinidazole; Antibiotics, e.g.
Amino-glycosides (such as Amikacin, Apramycin, Arbekacin,
Bambermycins, Butirosin, Dibekacin, Dihydrostreptomycin,
Fortimicin(s), Gentamicin, Isepamicin, Kaniamycin, Micronomicin,
Neomycin, Neomycin Undecylenate, Netilmicin, Paromomycin,
Ribostamycin, Sisomicin, Spectinomycin, Streptomycin, Tobramycin,
Trospectomycin, and the like), Amphenicols (such as Azidamfenicol,
Chloramphenicol, Florfenicol, Thiamphenicol, and the like),
Ansamycins (such as Rifamide, Rifampin, Rifamycin, Rifapentine,
Rifaximin, and the like), .beta.-Lactams (e.g., Carbacephems,
Loracarbef, Carbapenems (such as Biapenem, Imipenem, Meropenem,
Panipenem, and the like), Cephalosporins (such as Cefaclor,
Cefadroxil, Cefamandole, Cefatrizine, Cefazedone, Cefazolin,
Cefcapene Povoxil, Cefclidin, Cefdinir, Cefditoren, Cefepime
Cefetamet, Cefixime, Cefinenoxine, Cefodizime, Cefonicid,
Cefoperazone, Ceforanide, Cefotaxime, Cefotiam, Cefozopran,
Cefpimizole, Cefpiramide, Cefpirome, Cefpodoxime Proxetil,
Cefprozil, Cefroxadine, Cefsulodin, Ceftazidime, Cefteram,
Ceftezole, Ceftibuten, Ceftizoxime, Ceftriaxone, Cefuroxime,
Cefuzonam, Cephacetrile Sodium, Cephalexin, Cephaloglycin,
Cephaloridine, Cephalosporin, Cephalothin, Cephapirin Sodium,
Cephradine, Pivcefalexin, and the like), Cephamycins (such as
Cefbuperazone, Cefmetazole, Cefminox, Cefotetan, Cefoxitin, and the
like), Monobactams (such as Aztreonam, Carumonam, Tigemonam, and
the like), Oxacephens (such as Flomoxef, Moxalactam, and the like),
Penicillins (such as Amdinocillin, Amdinocillin Pivoxil,
Amoxicillin, Ampicillin, Apalcillin, Aspoxicillin, Azidocillin,
Azlocillin, Bacampicillin, Benzylpenicillic Acid, Benzylpenicillin
Sodium, Carbenicillin, Carindacillin, Clometocillin, Cloxacillin,
Cyclacillin, Dicloxacillin, Epicillin, Fenbenicillin, Floxacillin,
Hetacillin, Lenampicillin, Metampicillin, Methicillin Sodium,
Mezlocillin, Naacillin Sodium, Oxacillin, Penamecillin, Penethamate
Hydriodide, Penicillin G Benethamine, Penicillin G Benzathine,
Penicillin G Benzhydrylamine, Penicillin G Calcium, Penicillin G
Hydrabamine, Penicillin G Potassium, Penicillin G Procaine,
Penicillin N, Penicillin 0, Penicillin V, Penicllin V Benzathine,
Penicillin V Hydrabamine, Penimepicycline, Phenethicillin
Potassium, Piperacillin, Pivampicillin, Propicillin, Quinacillin,
Sulbenicillin, Sultamicillin, Talampicillin, Temocillin,
Ticarcillin, and the like), Ritipenem, Lincosamides (such as
Clindamycin, Lincomycin, and the like), Macrolides (such as
Azithromycin, Capbomycin, Clarithromycin, Dirithromycin,
Erythromycin, Erythromycin Acistrate, Erythromycin Estolate,
Erythromycin Glucoheptonate, Erythromycin Lactobionate,
Erythromycin Propionate, Erythromycin Stearate, Josamycin,
Leucomycins, Midecamycins, Miokamycin, Oleandomycin, Primycin,
Rokitamycin, Rosaramicin, Roxithromycin, Spiramycin,
Troleandomycin, and the like), Polypeptides (such as Amphomycin,
Bacitracin, Capreomycin, Colistin, Enduracidin, Enviomycin,
Fusafungine, Gramicidin S, Gramicidin(s), Mikamycin, Polymyxin,
Pristinamycin, Ristocetin, Teicoplanin, Thiostrepton,
Tuberactinomycin, Tyrocidine, Tyrothricin, Vancomycin, Viomycin,
Virginiamycin, Zinc Bacitracin, and the like), Tetracyclines (such
as Apicycline, Chlortetracycline, Clomocycline, Demeclocycline,
Doxycycline, Guamecycline, Lymecycline, Meclocycline, Methacycline,
Minocycline, Oxytetracycline, Penimepicycline, Pipacycline,
Rolitetracycline, Sancycline, Tetracycline, and the like),
Cycloserine, Mupirocin, Tuberin; synthetic antibacterial agents,
e.g. 2,4-Diaminopyrimidines (such as Brodimoprim, Textroxoprim,
Trimethoprim, and the like), Nitrofurans (such as Furaltadone,
Furazolium Chloride, Nifuradene, Nifuratel, Nifurfoline,
Nifurpirinol, Nifurprazine, Nifurtoinol, Nitrofirantoin, and the
like), Quinolones and Analogs (such as Cinoxacin, Ciprofloxacin,
Clinafloxacin, Difloxacin, Enoxacin, Fleroxacin, Flumequine,
Grepafloxacin, Lomefloxacin, Miloxacin, Nadifloxacin, Nadilixic
Acid, Norflaxacin, Ofloxacin, Oxolinic Acid, Pazufloxacin,
Pefloxacin, Pipemidic Acid, Piromidic Acid, Rosoxacin, Rufloxacin,
Sparfloxacin, Temafloxacin, Tosufloxacin, Trovafloxacin, and the
like), Sulfonamides (such as Acetyl Sulfamethoxpyrazine,
Benzylsulfamide, Chloramine-B, Chloramine-T, Dichloramine T,
N2-Formylsulfisomidine, N4- -D-Glucosylsulfanilamide, Mafenide,
4'-(Methylsulfamoyl)sulfanilanilide, Noprylsulfainide,
Phthalylsulfacetamide, Phthalylsulfathiazole, Salazosulfadimidine,
Succinylsulfathiazole, Sulfabenzamide, Sulfacetamide,
Sulfachlorpyridazine, Sulfachrysoidine, Sulfacytine, Sulfadiazine,
Sulfadicramide, Sulfadimethoxine, Sulfadoxine, Sulfaethidole,
Sulfaguanidine, Sulfaguanol, Sulfalene, Sulfaloxic, Sulfamerazine,
Sulfameter, Sulfamethazine, Sulfamethizole, Sulfamethomidine,
Sulfamethoxazole, Sulfamethoxypyridazine, Sulfametrole,
Sulfamidochrysoidine, Sulfamoxole, Sulfanilamide,
4-Sulfanilamidosalicylic Acid, N4-Sulfanilylsulfanilamide,
Sulfanilylurea, N-Sulfanilyl-3,4-xylamide, Sulfanitran,
Sulfaperine, Sulfaphenazole, Sulfaproxyline, Sulfapyrazine,
Sulfapyridine, Sulfasomizole, Sulfasymazine, Sulfathiazole,
Sulfathiourea, Sulfatolamide, Sulfisomidine, Sulfisoxazole, and the
like), Sulfones (such as Acedapsone, Acediasulfone, Acetosulfone
Sodium, Dapsone, Diathymosulfone, Glucosulfone Sodium, Solasulfone,
Succisulfone, Sulfanilic Acid, p-Sulfanilylbenzylamine, Sulfoxone
Sodium, Thiazolsulfone, and the like), Clofoctol, Hexedine,
Methenamine, Methenamine Anhydromethylenecitrate, Methenamine
Hippurate, Methenamine Mandelate, Methenamine Sulfosalicylate,
Nitroxoline, Taurolidine, Xibomol, and the like; leprostatic
antibacterial agents, such as Acedapsone, Acetosulfone Sodium,
Clofazimine, Dapsone, Diathymosulfone, Glucosulfone Sodium,
Hydnocarpic Acid, Solasulfone, Succisulfone, Sulfoxone Sodium, and
the like, antifungal agents such as Allylamines Butenafine,
Naftifine, Terbinafine, Imidazoles (e.g., Bifonazole, Butoconazole,
Cholordantoin, Chlormidazole, Cloconazole, Clotrimazole, Econazole,
Enilconazole, Fenticonazole, Flutrimazole, Isoconazole,
Ketoconazole, Lanoconazole, Miconazole, Omoconazole, Oxiconazole
Nitrate, Sertaconazole, Sulconazole, Tioconazole, and the like),
Thiocarbamates (e.g., Tolcilate, Tolindate, Tolnaftate, and the
like), Triazoles (e.g., Fluconazole, Itraconazole, Saperconazole,
Terconazole, and the like), Acrisorcin, Amorolfine, Biphenamine,
Bromosalicylchloranilide, Buclosamide, Calcium Propionate,
Chlorphenesin, Ciclopirox, Cloxyquin, Coparaffinate, Diamthazole
Dihydrochloride, Exalamide, Flucytosine, Halethazole, Hexetidine,
Loflucarban, Nifuratel, Potassium Iodide, Propionic Acid,
Pyrithione, Salicylanilide, Sodium Propionate, Sulbentine,
Tenonitrozole, Triacetin, Ujothion, Undecylenic Acid, Zinc
Propionate, etc.; or the like; analogs/derivatives thereof; salts
thereof; or combinations thereof.
[0138] Other antimicrobial agents useful in the present invention
include, but are not limited to, Q-lactamase inhibitors (e.g.
Clavulanic Acid, Sulbactam, Tazobactam, and the like);
Chldramphenicols (e.g. Azidamphenicol, Chloramphenicol,
Thiaphenicol, and the like); Fusidic Acid; synthetic agents such as
Trimethoprim, (optionally in combination with sulfonamides)
Nitroimidazoles (e.g., Metronidazole, Tinidazole, Nimorazole, and
the like), and the like; Antimycobacterial agents (e.g.,
Capreomycin, Clofazimine, Dapsone, Ethambutol, Isoniazid,
Pyrazinamide, Rifabutin, Rifampicin, Streptomycin, Thioamides, and
the like); Antiviral agents (e.g., Acryclovir, Amantadine,
Azidothymidine, Ganciclovir, Idoxuridine, Tribavirin, Trifluridine,
Vidarabine, and the like); Interferons; antiseptic agents (e.g.,
Chlorhexidine, Gentian violet, Octenidine, Povidone Iodine,
Quaternary ammonium compounds, Silver sulfadiazine, Triclosan, and
the like); or the like; analogs/derivatives thereof; salts thereof;
or combinations thereof.
[0139] In some embodiments, the active agent may include, but is
not limited to, collagen (e.g., Type 1), osteonectin, bone
sialoproteins (Bsp), alpha-2HS-glycoproteins, bone Gla-protein
(Bgp), matrix Gla-protein, bone phosphoglycoprotein, bone
phosphorprotein, bone proteoglycan, protolipids, bone morphogenic
proteins (e.g., BMP-1, -2A, -2B, -3, -3b, -4, -5, -6, -7, -8, -8b,
-9, -10, -11, -12, -13, -14, -15), cartilage induction factor,
platelet derived growth factor (PDGF-1, -2), endothelial cell
growth factors (ECGF-1, -2a, -2b), skeletal growth factor
(SKF=IGF-2), insulin-like growth factors (IGF-1, IGF-2), fibroblast
growth factor (ODGF-I, -2, -3, -4, -5, -6, -7, -8, -9, -10, -11,
-12, -13, -14, -15, -16, -17, -18, -19, -20, -21, -22, -23), colony
stimulating factor, transforming growth factor (e.g., TGF-.alpha.,
TGF-.beta., or the like), vascular endothelial growth factors
(VEGF), growth/differentiation factors (GDF-1, -3, -5, -6, -7, -8,
-9, -9B, -10, -11, -15, -16), osteogenic proteins (OP-1=BMP-7,
OP-2=BMP-8, OP-3=BMP-8b), bone growth hormone, parathyroid hormone
(PTH), insulin, calcitonin, and the like, and combinations thereof.
Additionally or alternately, the active agents may include proteins
associated with cartilage, such as chondrocalcining protein;
proteins associated with dentin, such as phosphophoryn,
glycoproteins and Gla proteins; proteins associated with enamel
such as amelognin and enamelin; structural proteins such as fibrin,
fibrinogen, keratin, tubulin, elastin, and the like; blood
proteins, whether in plasma or serum, e.g., serum albumin;
non-protein growth factors such as prostaglandins and statins
(e.g., Simvastatin, Lovastatin, or the like); or the like;
analogs/derivatives thereof; salts thereof; or combinations
thereof.
[0140] In another embodiment, the active agent can include amino
acids, anabolics, analgesics and antagonists, anesthetics,
angiogenesis agents, anti-angiogenetic agents, antihelmintics,
anti-adrenergic agents, anti-asthmatics, anti-atherosclerotics,
antibacterials, anticholesterolics, anticholinergics,
anti-coagulants, antidepressants, antidotes, anti-emetics,
anti-epileptic drugs, anti-fibrinolytics, antihistamines,
anti-inflammatory agents, antihypertensives, antimetabolites,
antimigraine agents, antimycotics, antinauseants, antineoplastics,
anti-obesity agents, anti-Parkinson agents, antiprotozoals,
antipsychotics, antirheumatics, antiseptics, antivertigo agents,
antivirals, appetite stimulants, bacterial vaccines, bioflavonoids,
calcium channel blockers, capillary stabilizing agents, coagulants,
corticosteroids, detoxifying agents for cytostatic treatment,
diagnostic agents (like contrast media and radioisotopes), drugs
for treatment of chronic alcoholism, drugs targeting dopaminergic
pathways, electrolytes, enzymes, enzyme inhibitors, ferments,
ferment inhibitors, gangliosides and ganglioside derivatives,
hemostatics, hormones, hormone antagonists, hypnotics,
immunomodulators, immunostimulants, immuno-suppressants, minerals,
muscle relaxants, neuromodulators, neurotransmitters and
neurotropics, osmotic diuretics, parasympatholytics,
para-sympathomimetics, peptides, proteins, psychostimulants,
respiratory stimulants, sedatives, serum lipid reducing agents,
smooth muscle relaxants, sympatholytics, sympathomimetics,
vasodilators, vasoprotectives, vectors for gene therapy, viral
vaccines, viruses, vitamins, oligonucleotides and derivatives, or
the like, or analogs/derivatives thereof, salts thereof, and/or
combinations thereof.
[0141] In another embodiment, the active agent can include
antimicrobial agents, analgesics, antiinflammatory agents, counter
irritants coagulation modifying agents, diuretics,
sympathomimetics, anorexics, antacids and other gastrointestinal
agents, antiparasitics, antidepressants, antihypertensives,
anticholinergics, stimulants, antihormones, central and respiratory
stimulants, drug antagonists, lipid-regulating agents, uricosurics,
cardiac glycosides, electrolytes, ergot and derivatives thereof,
expectorants, hypnotics and sedatives, antidiabetic agents,
dopaminergic agents, antiemetics, muscle relaxants,
para-sympathomimetics, anticonvulsants, antihistamines,
beta-blockers, purgatives, antiarrhytmics, contrast materials,
radiopharmaceuticals, antiallergic agents, tranquilizers,
vasodilators, antiviral agents, and antineoplastic or cytostatic
agents or other agents with anticancer properties, vitamins
(including micro- and macro-nutrients), or a combination
thereof.
[0142] In another embodiment, the active agent includes an
anti-muscle spasm agent, anti-spasmodic, bone resorption inhibitor,
smooth muscle contractile agent, calcium absorption enhancer,
muscle relaxant, or a mixture thereof. Suitable anti-muscle spasm
agents include, but are not limited to, baclofen, botulinum toxin,
carisoprodol, chlorphenesin, chlorzoxazone, cyclobenzaprine,
dantrolene, diazepam, metaxalone, methocarbamol, orphenadrine,
tizanidine, and mixtures thereof. Suitable anti-spasmodics include,
but are not limited to, atropine, baclofen, dicyclomine, hyoscine,
propatheline, oxybutynin, S-oxybutynin, tizanidine, cevimeline,
chlordiazepoxide, hydrochloride, dicyclomine, hyoscine,
hyoscyamine, glycopyrrolate, and mixtures thereof. Suitable bone
resorption inhibitors include, but are not limited to alendronate,
ibandronate, minodronate, risedronate, etidronate, tiludronate, and
mixtures thereof. A suitable smooth muscle contractile agent
includes, but is not limited to, hyoscine, and mixtures thereof.
Suitable calcium absorption enhancers include, but are not limited
to, alfacalcidol, calcitriol, and mixtures thereof. Suitable muscle
relaxants include, but are not limited to, baclofen, carisoprodol,
chlorphenesin, chlorzoxazone, cyclobenzaprine, dantrolene,
diazepam, metaxalone, methocarbamol, orphenadrine, and mixtures
thereof.
[0143] In another embodiment, the active agent includes an
anti-diuretic, anti-muscle spasm agent, anti-spasmodic, agent for
treating urinary incontinence, anti-diarrheal agent, agent for
treating nausea and/or vomiting, smooth muscle contractile agent,
anti-secretory agent, enzyme, anti-ulcerant, bile acid replacement
and/or gallstone solubilizing drug, or a mixture thereof. Suitable
anti-diuretics include, but are not limited to, acetazolamide,
benzthiazide, bendroflumethazide, bumetanide, chlorthalidone,
chlorothiazide, ethacrynic acid, furosemide, hydrochlorothiazide,
hydroflumethiazide, methyclothiazide, polythiazide, quinethazone,
spironolactone, triamterene, torsemide, trichlomethiazide,
desmopressin, oxytocin, and mixtures thereof. Suitable anti-muscle
spasm agents include, but are not limited to, baclofen, botulinum
toxin, carisoprodol, chlorphenesin, chlorzoxazone, cyclobenzaprine,
dantrolene, diazepam, metaxalone, methocarbamol, orphenadrine,
tizanidine, and mixtures thereof. Suitable anti-spasmodics include,
but are not limited to, atropine, baclofen, dicyclomine, hyoscine,
propatheline, oxybutynin, S-oxybutynin, tizanidine, and mixtures
thereof. Suitable agents for treating urinary incontinence include,
but are not limited to, darifenacin, vamicamide, detrol, ditropan,
imipramine, and mixtures thereof. Suitable anti-diarrheal agents
include, but are not limited to, ondansetron, palnosetron,
tropisetron, attapulgite, atropine, bismuth, diphenoxylate,
loperamide, and mixtures thereof. Suitable agents for treating
nausea and/or vomiting include, but are not limited to, alosetron,
dolasetron, granisetron, meclizine, metoclopramide, ondansetron,
palnosetron, prochloperazine, promethazine, trimethobenzamiode,
tropisetron, and mixtures thereof. A suitable smooth muscle
contractile agent includes, but is not limited to, hyoscine.
Suitable anti-secretory agents include, but are not limited to,
esomeprazole, lansoprazole, omeprazole, pantoprazole, rabeprazole,
tenetoprazole, ecabet, misoprostol, teprenone, and mixtures
thereof. Suitable enzymes include, but are not limited to,
alpha-galactosidase, alpha-L-iduronidase, imiglucerase/alglucerase,
amylase, lipase, protease, pancreatin, olsalazine, and mixtures
thereof. Suitable anti-ulcerants include, but are not limited to,
cimetidine, ranitidine, famotidine, misoprostol, sucralfate,
pantoprazole, lansoprazole, omeprazole, and mixtures thereof. A
suitable bile acid replacement and/or gallstone solubilizing drug
includes, but is not limited to, ursodiol.
[0144] In another embodiment, the active agent includes an
endocrine modulator, glucose production inhibitor, agent for
treatment of type II diabetes, anti-secretory agent, glycolipid,
glycoprotein, anti-hyperthyroid agent, thyroid hormone, or a
mixture thereof. Suitable endocrine modulators include, but are not
limited to, methimazole, voglibose, finasteride, GI198745,
liothyronine, glyburide, metformin, nateglinide, ioglitazone,
pegvisomant, minoxidil, and mixtures thereof. Suitable glucose
production inhibitors include, but are not limited to, acarbose,
acetohexamide, chlorpropamide, glipizide, glyburide, metformin,
miglitol, nateglinide, pioglitazone, rosiglitazone, tolbutamide,
tolazamide, and mixtures thereof. Suitable agents for treatment of
type II diabetes include, but are not limited to, acarbose,
acetohexamide, chlorpropamide, glipizide, glyburide, metformin,
miglitol, nateglinide, pioglitazone, rosiglitazone, tolbutamide,
tolazamide, and mixtures thereof. Suitable anti-secretory agents
include, but are not limited to, esomeprazole, lansoprazole,
omeprazole, pantoprazole, rabeprazole, tenetoprazole, ecabet,
misoprostol, teprenone, and mixtures thereof. Suitable glycolipids
include, but are not limited to imigulcerase, vancomycin, vevesca
(OGT 918), GMK vaccine, and mixtures thereof. Suitable
glycoproteins include, but are not limited to, staphvax,
bimosiamose (TBC1269), GCS-100, heparin, and mixtures thereof.
Suitable anti-hyperthyroid agents include, but are not limited to,
methimazol, propylthiouracil, and mixtures thereof.
[0145] In another embodiment, the active agent includes a
cholesterol-lowering agent, aldosterone antagonist,
triglyceride-lowering agent, leukotriene receptor antagonist,
immunomodulator or immunogen, glucose production inhibitor, agent
for treatment of type II diabetes, bone resorption inhibitor,
calcium absorption enhancer, insulin enhancing agent, insulin
sensitizer, cytokine, metabolic regulator, mast cell mediator,
eosinophil and/or mast cell antagonist, glycolipid, glycoprotein,
anti-inflammatory drug, anti-obesity drug, COX (cyclooxygenase)
and/or LO (lipoxygenase) inhibitor, or a mixture thereof. Suitable
cholesterol-lowering agents include, but are not limited to,
atorvastatin, benzofibrate, bezafibrate, cerivastatin,
cholestyramine, ciprofibrate, clofibrate, colesevelam, colestipol,
ezetimibe, fluvastatin, gemfibrozil, lovastatin, niacin/lovastatin,
pravastatin, probucol, rosuvastatin, and simvastatin. A suitable
aldosterone antagonist includes, but is not limited to,
spironolactone. A suitable triglyceride-lowering agent includes,
but is not limited to, fenofibrate. Suitable immunomodulators or
immunogens include, but are not limited to, interferon beta 1A,
interferon beta 1B. Suitable glucose production inhibitors include,
but are not limited to, acarbose, acetohexamide, chlorpropamide,
glipizide, glyburide, metformin, miglitol, nateglinide,
pioglitazone, rosiglitazone, tolbutamide, and tolazamide. Suitable
insulin enhancing agents include, but are not limited to,
acamprosate, miglitol, troglitazone, chlorpropamide, glimepiride,
glipizide, glyburide, and repaglinide. A suitable insulin
sensitizer includes, but is not limited to, is BRL 49653. Suitable
cytokines include, but are not limited to, darbepoetin alfa,
epoetin alpha, erythropoietin, and NESP. Suitable metabolic
regulators include, but are not limited to, allopurinol and
oxypurinol. A suitable eosinophil and/or mast cell antagonists
includes, but is not limited to, nedocromil. Suitable
anti-inflammatory drugs include, but are not limited to, alosetron,
anakinra, beclomethasone, betamethasone, budesonide, clobetasol,
celecoxib, cromolyn, desoximetasone, dexamethasone, epinastic,
etanercept, etoricoxib, flunisolide, fluocinonide, fluticasone,
formoterol, hydrocortisone, hydroxychloroquine, ibudilast,
ketotifen, meloxicam, mesalamine, methotrexate, methylprednisolone,
mometasone, montelukast, nedocromil, olsalazine, prednisone,
ramatroban, rofecoxib, salsalate, terbutaline, triamcinolone,
valdecoxib, and zafirlukast. Suitable anti-obesity drugs include,
but are not limited to, dexedrine, diethylpropion, mazindol,
oleoyl-estrone, phentermine, phendimetrazine, and sibutramine. A
suitable COX and/or LO inhibitor includes, but is not limited to,
is ML-3000.
[0146] In another embodiment, the active agent includes an
anti-arrhythmic, anti-hypertensive, heart regulator, cardiovascular
agent, plaque stabilization agent, vasodilator, anti-anginal,
anti-coagulant, anti-hypotensive, anti-thrombotic, drug for
treating congestive heart failure, p-FOX (fatty acid oxidation)
inhibitor, or a mixture thereof. Suitable anti-arrhythmics include,
but are not limited to, adenosine, amiodarone, bepridil, bretylium,
digitoxin, digoxin, diltiazem, disopyramide, dofetilide, D-sotolol,
flecainide, lidocaine, mexiletine, milrinone, phenyloin,
pilsicainide, procainamide, propafenone, propranolol, quinidine,
tocainide, dofetilide, and mixtures thereof. Suitable
anti-hypertensives include, but are not limited to, acebutolol,
alfuzosin, amlodipine, atenolol, amlodipine/benazepril, barnidipine
benazepril, bepridil, betaxolol, bisoprolol, bosentan, candesartan,
captopril, cariporide, carvedilol, celiprolol, cilazapril,
clonidine, diltiazem, doxazosin, enalapril, eplerenone, eprosartan,
esmolol, felodipine, fenoldopam, fosinopril, guanfacine, imidapril,
irbesartan, isradipine, labetalol, lercanidipine, lisinopril,
losartan, manidipine, methyldopa, metoprolol, moxonidine, nadolol,
nicardipine, nicorandal, nifedipine, nitrendipine, nosoldipine,
omapatrilat, perindopril erbumine, pindolol, prazosin, propranolol,
quinapril, ramipri, sotalol, spirapril, tamsulosin, telmisartan,
terazosin, torsemide, trandolapril, valsartan, vatanidipine,
midodrine, and mixtures thereof. Suitable heart regulators include,
but are not limited to, digoxin, digitoxin, dobutamine, and
mixtures thereof. Suitable cardiovascular agents include, but are
not limited to, edaravone, iloprost, levosimendan, molsidomine,
tezosentan, tirilazad, YM087, adenosine, avasimibe, fenofibrate,
and mixtures thereof. A suitable plaque stabilization agent
includes, but is not limited to, avasimibe. Suitable vasodilators
include, but are not limited to, buflomedil, cilostazol,
dipyridamole, diazoxide, hydralazine, minoxidil, naftidrofuryl,
nicorandil, nitroprusside, alprostadil, apomorphine, phentolamine
mesylate, sildenafil, tadalafil, vardenifil, and mixtures thereof.
Suitable anti-anginals include, but are not limited to,
amilodipine, amyl nitrite, atenolol, bepridil, diltiazem,
erythrityl tetranitrate, felodipine, isosorbide dinitrate,
isradipine, metoprolol, nadolol, nicardipine, nifedipine,
nimodipine, pentaerythritol tetranitrate, propranolol, and mixtures
thereof. Suitable anti-coagulants include, but are not limited to,
abciximab, ardeparin, argatroban, bivalirudin, clopidogrel,
dalteparin, danaparoid, desirudin, dipyridamole, enoxaparin,
eptifibatide, fondaparinux, H376/95, lepirudin, melagatran,
nadroparine, nafamostat mesilate, pentosan, pentoxifylline,
reviparin, sarpogrelate, SNAC/SNAD-heparin, ticlopidine,
tinzaparin, tirofiban, warfarin, and mixtures thereof. Suitable
anti-hypotensives include, but are not limited to, midodrine,
dobutamine, fludrocortisone, and mixtures thereof. Suitable
anti-thrombotics include, but are not limited to, aspirin,
abciximab, enoxaparin, integrelin, ticlopidine, and mixtures
thereof. Suitable drugs for treating congestive heart failure
include, but are not limited to, amrinone, benazepril, bumetanide,
captopril, digitoxin, digoxin, dobutamine, dopamine, enalapril,
ethacrynic acid, fosinopril, furosemide, hydralazine, lisinopril,
milrinone, minoxidil, moexipril, quinapril, ramipril, torsemide,
and mixtures thereof. A suitable p-FOX inhibitor includes, but is
not limited to, ranolazine.
[0147] In another embodiment, the active agent includes an
aldosterone antagonist, immunomodulator or immunogen,
immunosuppressant, cytokine, leukotriene receptor antagonist, mast
cell mediator, eosinophil and/or mast cell antagonist, mucolytic,
glucocorticoid, glycolipid, or a mixture thereof. A suitable
aldosterone antagonist includes, but is not limited to,
spironolactone. Suitable immuno-suppressants include, but are not
limited to, azathioprine, cyclophosphamide, cyclosporine, ERL 080,
enlimomab, methotrexate, mitoxantrone, mycophenolate, mofetil,
sirolimus, tacrolimus (FK-506), and mixtures thereof. Suitable
mucolytics for use in the buccal sprays of the invention include,
but are not limited to, ambroxol, bromhexin, fudostein,
acetylcestine, and mixtures thereof.
[0148] In another embodiment, the active compound is a p-FOX (fatty
acid oxidation) inhibitor, acetylcholinesterase inhibitor, nerve
impulse inhibitor, anti-cholinergic, anti-convulsant,
anti-psychotic, anxiolytic agent, dopamine metabolism inhibitor,
agent to treat post stroke sequelae, neuroprotectant, agent to
treat Alzheimer's disease, neurotransmitter, neurotransmitter
agonist, sedative, agent for treating attention deficit disorder,
agent for treating narcolepsy, central adregenic antagonist,
anti-depression agent, agent for treating Parkinson's disease,
benzodiazepine antagonist, stimulant, neurotransmitter antagonist,
tranquilizer, or a mixture thereof. Suitable acetylcholinesterase
inhibitors include, but are not limited to, galantamine,
neostigmine, physostigmine, and edrophonium. Suitable nerve impulse
inhibitors include, but are not limited to, levobupivacaine,
lidocaine, prilocaine, mepivacaine, propofol, rapacuronium bromide,
ropivacaine, tubocurarine, atracurium, doxaurium, mivacurium,
pancuronium, vercuronium, pipecuronium, and rocuronium. Suitable
anti-cholinergics for use in the buccal sprays of the invention
include, but are not limited to, amantadine, ipratropium,
oxitropium, and dicycloverine. Suitable anti-convulsants include,
but are not limited to, acetazolamide, carbamazepine, clonazepam,
diazepam, divalproex (valproic acid), ethosuximide, lamotrignine
acid, levetriacetam, oxcarbazepine, phenobarbital, phenytoin,
pregabalin, primidone, remacemide, trimethadione, topiramate,
vigabatrin, and zonisamide. Suitable anti-psychotics include, but
are not limited to, amisulpride, aripiprazole bifemelane,
bromperidol, clozapine, chlorpromazine, haloperidol, iloperidone
loperidone, olanzapine, quetiapine, fluphenazine, fumarate,
risperidone, thiothixene, thioridazine, sulpride, and ziprasidone.
Suitable anxiolytic agents include, but are not limited to,
amitryptiline, atracurium, buspirone, chlorzoxazone, clorazepate,
cisatracurium, cyclobenzaprine, eperisone, esopiclone, hydroxyzine,
mirtazapine, mivacurium, pagoclone, sulperide, zaleplon, and
zopiclone. Suitable dopamine metabolism inhibitors include, but are
not limited to, entacapone, lazebemide, selegiline, and tolcapone.
Suitable agents to treat post stroke sequelae include, but are not
limited to, glatiramer, interferon beta 1A, interferon beta 1B,
estradiol, and progesterone. Suitable neuron-protectants include,
but are not limited to, donepezil, memanine, nimodipine, riluzole,
rivastigmine, tacrine, TAK147, and xaliproden. Suitable agents to
treat Alzheimer's disease include, but are not limited to,
carbidopa, levodopa, tacrine, donezepil, rivastigmine, and
galantamine. Suitable neurotransmitters include, but are not
limited to, acetylcholine, serotonin, 5-hydroxytryptamine (5-HT),
GABA, glutamate, aspartate, glycine, histamine, epinephrine,
norpinephrine, dopamine, adenosine, ATP, and nitric oxide. Suitable
neurotransmitter agonists include, but are not limited to,
almotriptan, aniracetam, atomoxetine, benserazide, bromocriptine,
bupropion, cabergoline, citalopram, clomipramine, desipramine,
diazepam, dihydroergotamine, doxepin duloxetine, eletriptan,
escitalopram, fluvoxamine, gabapentin, imipramine, moclobemide,
naratriptan, nefazodone, nefiracetam acamprosate, nicergoline,
nortryptiline, paroxetine, pergolide, pramipexole, rizatriptan,
ropinirole, sertraline, sibutramine, sumatriptan, tiagabine,
trazodone, venlafaxine, and zolmitriptan. Suitable sedatives
include, but are not limited to, dexmedetomidine, eszopiclone,
indiplon, zolpidem, and zaleplon. Suitable agents for treating
attention deficit disorder include, but are not limited to,
amphetamine, dextroamphetamine, methylphenidate, and pemoline.
Suitable agents for treating narcolepsy include, but are not
limited to, modafinil and mazindol. A suitable central adregenic
antagonist includes, but is not limited to, mesoridazine. Suitable
anti-depression agents include, but are not limited to,
amitriptyline, amoxapine, bupropion, clomipramine, clomipramine,
clorgyline, desipramine, doxepin, fluoxetine, imipramine,
isocarboxazid, maprotiline, mirtazapine, nefazodone, nortriptyline,
paroxetine, phenelzine, protriptyline, sertraline, tranylcypromine,
trazodone, and venlafaxine. Suitable agents for treating
Parkinson's disease include, but are not limited to, amantadine,
bromocriptine, carvidopa, levodopa, pergolide, and selegiline. A
suitable benzodiazepine antagonist includes, but is not limited to,
flumazenil. A suitable neuron-transmitter antagonist includes, but
is not limited, to deramciclane. Suitable stimulants include, but
are not limited to, amphetamine, dextroamphetamine, dinoprostone,
methylphenidate, methylphenidate, modafinil, and pemoline. A
suitable tranquilizer includes, but is not limited to,
mesoridazine.
[0149] In another embodiment, the active agent includes a nerve
impulse inhibitor. Suitable nerve impulse inhibitors include, but
are not limited to levobupivacaine, lidocaine, prilocalne,
mepivacaine, propofol, rapacuronium bromide, ropivacaine,
tubocurarine, atracurium, doxacurium, mivacurium, pancuronium,
vecuronium, pipecuronium, rocuronium, and mixtures thereof.
[0150] In another embodiment, the active agent includes an
anti-opioid agent. Suitable anti-opioid agents for use in the
buccal sprays of the invention include, but are not limited to,
naloxone, nalmefene, naltrexone, cholecystokinin, nociceptin,
neuropeptide FF, oxytocin, vasopressin, and mixtures thereof.
[0151] In another embodiment, the active agent includes an
anti-migraine agent. Suitable anti-migraine agents for use in the
buccal sprays of the invention include, but are not limited to,
frovatriptan, zolmitriptan, rizatriptan, almotriptan, eletriptan,
naratriptan, almotriptan, ergotamine, diethylergotamine,
sumatriptan, and mixtures thereof.
[0152] In another embodiment, the active agent includes a pain
control agent. Suitable pain control agents for use in the buccal
sprays of the invention include, but are not limited to,
non-steroidal anti-inflammatory drugs, alfentanil, butorphanol,
codeine, dezocine, fentanyl, hydrocodone, hydromorphone,
levorphanol, meperidine, methadone, morphine, nalbuphine,
oxycodone, oxymorphone, propoxyphene, pentazocine, sufentanil,
tramadol, and mixtures thereof.
[0153] In another embodiment, the active agent includes an
anesthetic. Suitable anesthetics for use in the buccal sprays of
the invention include, but are not limited to, benzonatate,
bupivacaine, desflurane, enflurane, isoflurane, levobupivacaine,
lidocaine, mepivacaine, prilocalne, propofol, rapacuronium bromide,
ropivacaine, sevoflurane, ketamine, and mixtures thereof.
[0154] In another embodiment, the active agent can include, but is
not limited to, cyclosporine, sermorelin, octreotide acetate,
calcitonin-salmon, insulin lispro, sumatriptan succinate,
clozepine, cyclobenzaprine, dexfenfluramine hydrochloride,
glyburide, zidovudine, erythromycin, ciprofloxacin, ondansetron
hydrochloride, dimenhydrinate, cimetidine hydrochloride,
famotidine, phenyloin sodium, phenyloin, carboprost thromethamine,
carboprost, diphenhydramine hydrochloride, isoproterenol
hydrochloride, terbutaline sulfate, terbutaline, theophylline,
albuterol sulfate, neutraceuticals (i.e., nutrients with
pharmacological action, e.g., carnitine, valerian, echinacea, and
the like), or the like; analogs/derivatives thereof;
salts/alternate salts thereof; or combinations thereof.
[0155] Any opioid or non-.mu.-opioid, a pharmaceutically acceptable
salt thereof, a base form thereof, or mixture of any combination of
such opioids and/or their derivatives that are known in the art can
be included. Opioids believed to have at least some .mu.-opioid
receptor agonist activity (and optionally at least some agonist
activity also at one or more of the .kappa.-opioid receptor, the
.delta.-opioid receptor, and the ORL-1 receptor) include, but are
not limited to, alfentanil, allylprodine, alphaprodine,
anileridine, benzylmorphine, bezitramide, buprenorphine,
butorphanol, clonitazene, codeine, desomorphine, dextromoramide,
dezocine, diampromide, diamorphone, dihydrocodeine,
dihydromorphine, dihydromorphone, dihydroisomorphine, dimenoxadol,
dimepheptanol, dimethylthiambutene, dioxaphetyl butyrate,
dipipanone, eptazocine, ethoheptazine, ethylmethylthiambutene,
ethylmorphine, etonitazene, etorphine, dihydroetorphine, fentanyl,
heroin, hydrocodone, hydromorphone, hydromorphodone,
hydroxypethidine, isomethadone, ketobemidone, levorphanol,
levophenacylmorphan, lofentanil, meperidine, meptazinol,
metazocine, methadone, metopon, morphine, myrophine, narceine,
nicomorphine, norlevorphanol, normethadone, nalorphine, nalbuphene,
normorphine, norpipanone, opium, oxycodone, oxymorphone, pantopon,
papaveretum, paregoric, pentazocine, phenadoxone, phendimetrazine,
phendimetrazone, phenomorphan, phenazocine, phenoperidine,
piminodine, piritramide, propheptazine, promedol, properidine,
propoxyphene, propylhexedrine, sufentanil, tilidine, tramadol, and
mixtures thereof. Non-.mu.-opioids include, but are not limited to,
ORL-1-specific opioid agonists, such as nociceptin, deltorphin, and
the like, and mixtures thereof. In a preferred embodiment, the
opioid includes buprenorphine, pharmaceutically acceptable salts
thereof, base forms thereof, fentanyl, pharmaceutically acceptable
salts thereof, base forms thereof, oxycodone, pharmaceutically
acceptable salts thereof, base forms thereof, and any combination
of such opioids and/or their derivatives.
[0156] In certain embodiments, the opioid agonist includes
hydrocodone, morphine, hydromorphone, oxycodone, codeine,
levorphanol, meperidine, methadone, oxymorphone, buprenorphine,
fentanyl, dipipanone, heroin, tramadol, etorphine,
dihydroetorphine, butorphanol, levorphanol, pharmaceutically
acceptable salts thereof, base forms thereof, and any and all
mixtures thereof. The opioid agonist can, in some embodiments,
include oxycodone, hydrocodone, fentanyl, buprenorphine,
pharmaceutically acceptable salts thereof, base forms thereof, and
any and all mixtures thereof. The opioid agonist can, in other
embodiments, include buprenorphine, pharmaceutically acceptable
salts thereof, base forms thereof, fentanyl, pharmaceutically
acceptable salts thereof, base forms thereof, and any combination
of such opioids and/or their derivatives.
[0157] General categories of active agents can, in one embodiment,
include, but are not limited to: ACE inhibitors; adenohypophyseal
hormones; adrenergic neuron blocking agents; adrenocortical
steroids; inhibitors of the biosynthesis of adrenocortical
steroids; alpha-adrenergic agonists; alpha-adrenergic antagonists;
selective alpha-two-adrenergic agonists; androgens; anti-addictive
agents; antiandrogens; anti-infectives, such as antibiotics,
antimicrobials, and antiviral agents; analgesics and analgesic
combinations; anorexics; antihelmintics; antiarthritics;
antiasthmatic agents; anticonvulsants; antidepressants;
antidiabetic agents; antidiarrheals; antiemetic and prokinetic
agents; antiepileptic agents; antiestrogens; antifungal agents;
antihistamines; antiinflammatory agents; antimigraine preparations;
antimuscarinic agents; antinauseants; antineoplastics;
antiparasitic agents; antiparkinsonism drugs; antiplatelet agents;
antiprogestins; antipruritics; antipsychotics; antipyretics;
antispasmodics; anticholinergics; antithyroid agents; antitussives;
azaspirodecanediones; sympathomimetics; xanthine derivatives;
cardiovascular preparations, including potassium and calcium
channel blockers, alpha blockers, beta blockers, and
antiarrhythmics; antihypertensives; diuretics and antidiuretics;
vasodilators, including general coronary, peripheral, and cerebral;
central nervous system stimulants; vasoconstrictors; cough and cold
preparations, including decongestants; hormones, such as estradiol
and other steroids, including corticosteroids; hypnotics;
immunosuppressives; muscle relaxants; parasympatholytics;
psychostimulants; sedatives; tranquilizers; nicotine and acid
addition salts thereof; benzodiazepines; barbituates;
benzothiadiazides; beta-adrenergic agonists; beta-adrenergic
antagonists; selective beta-one-adrenergic antagonists; selective
beta-two-adrenergic antagonists; bile salts; agents affecting
volume and composition of body fluids; butyrophenones; agents
affecting calcification; catecholamines; cholinergic agonists;
cholinesterase reactivators; dermatological agents;
diphenylbutylpiperidines; ergot alkaloids; ganglionic blocking
agents; hydantoins; agents for control of gastric acidity and
treatment of peptic ulcers; hematopoietic agents; histamines;
5-hydroxytryptamine antagonists; drugs for the treatment of
hyperlipiproteinemia; laxatives; methylxanthines; moncamine oxidase
inhibitors; neuron-muscular blocking agents; organic nitrates;
pancreatic enzymes; phenothiazines; prostaglandins; retinoids;
agents for spasticity and acute muscle spasms; succinimides;
thioxanthines; thrombolytic agents; thyroid agents; inhibitors of
tubular transport of organic compounds; drugs affecting uterine
motility; vitamins; and the like; or a combination thereof.
[0158] Alternately or in addition to an opioid agonist, another
active compound may be added including, but not limited to,
flurogestone acetate, hydroxyprogesterone, hydroxyprogesterone
acetate, hydroxyprogesterone caproate, medroxy-progesterone
acetate, norethindrone, norethindrone acetate, norethisterone,
norethynodrel, desogestrel, 3-keto desogestrel, gestadene,
levonorgestrel, estradiol, estradiol benzoate, estradiol valerate,
estradiol cyprionate, estradiol decanoate, estradiol acetate,
ethynyl estradiol, estriol, estrone, mestranol, betamethasone,
betamethasone acetate, cortisone, hydrocortisone, hydrocortisone
acetate, corticosterone, fluocinolone acetonide, prednisolone,
prednisone, triamcinolone, aldosterone, androsterone, testosterone,
methyl testosterone, or a combination thereof.
[0159] Alternately or in addition to an opioid agonist, another
active compound may be added including, but not limited to: a)
corticosteroids, e.g., cortisone, hydrocortisone, prednisolone,
beclomethasone propionate, dexamethasone, betamethasone,
flumethasone, triamcinolone, triamcinolone acetonide, fluocinolone,
fluocinolone acetonide, fluocinolone acetate, clobetasol
propionate, or the like, or a combination thereof; b) analgesic
anti-inflammatory agents, e.g., acetaminophen, mefenamic acid,
flufenamic acid, indomethacin, diclofenac, diclofenac sodium,
alclofenac, ibufenac, oxyphenbutazone, phenylbutazone, ibuprofen,
flurbiprofen, ketoprofen, salicylic acid, methylsalicylate,
acetylsalicylic acid, 1-menthol, camphor, slindac, tolmetin sodium,
naproxen, fenbufen, or the like, or a combination thereof; c)
hypnotic sedatives, e.g., phenobarbital, amobarbital,
cyclobarbital, lorazepam, haloperidol, or the like, or a
combination thereof; d) tranquilizers, e.g., fulphenazine,
thioridazine, diazepam, flurazepam, chlorpromazine, or the like, or
a combination thereof; e) antihypertensives, e.g., clonidine,
clonidine hydrochloride, bopinidol, timolol, pindolol, propranolol,
propranolol hydrochloride, bupranolol, indenolol, bucumolol,
nifedipine, bunitrolol, or the like, or a combination thereof; f)
hypotensive diuretics, e.g., bendroflumethiazide, polythiazide,
methylchlorthiazide, trichlormethiazide, cyclopenthiazide, benzyl
hydrochlorothiazide, hydrochlorothiazide, bumetanide, or the like,
or a combination thereof; g) antibiotics, e.g., penicillin,
tetracycline, oxytetracycline, metacycline, doxycycline,
minocycline, fradiomycin sulfate, erythromycin, chloramphenicol, or
the like, or a combination thereof; h) anesthetics, e.g.,
lidocaine, benzocaine, ethylaminobenzoate, or the like, or a
combination thereof; i) antimicrobial agents, e.g., benzalkonium
chloride, nitrofurazone, nystatin, sulfacetamide, clotriamazole, or
the like, or a combination thereof; j) anti-fungal agents, e.g.,
pentamycin, amphotericin B, pyrrol nitrin, clotrimazole, or the
like, or a combination thereof; k) vitamins, e.g., vitamin A,
ergocalciferol, cholecalciferol, octotriamine, riboflavin butyric
acid ester, or the like, or a combination thereof; l)
antiepileptics, e.g., nitrazepam, meprobamate, clonazepam, or the
like, or a combination thereof; m) antihistamines, e.g.,
diphenhydramine hydrochloride, chlorpheniramine, diphenylimidazole,
or the like, or a combination thereof; n) antitussives, e.g.,
dextromethorphan, terbutaline, ephedrine, ephedrine hydrochloride,
or the like, or a combination thereof; o) sex hormones, e.g.,
progesterone, estradiol, estriol, estrone, or the like, or a
combination thereof; p) antidepressants, e.g., doxepin; q)
vasodilators, e.g., nitroglycerin, isosorbide nitrate, nitroglycol,
pentaerythritol tetranitrate, dipyridamole, or the like, or a
combination thereof; r) other drugs, e.g., 5-fluorouracil,
dihydroergotamine, desmopressin, digoxin, methoclopramide,
domperidone, scopolamine, scopolamine hydrochloride, or the like,
or a combination thereof; or the like; or a combination
thereof.
[0160] In another embodiment, the active agent can include, but is
not limited to, anti-staphylococcal agents (e.g., YSPXTNF, YSPWRNF,
YSPWTNF-NH.sub.2, GENBANK/AF202641, GENBANK/AF205220,
GENBANK/AAG03056, or the like, or combinations thereof. Other
agents that modulate the production or secretion of bacterial or
microbial toxins or virulence factors may also be used as active
agents. For instance, thiolactones and bacterial toxin regulatory
proteins such as RNAIII-inhibiting peptides (RIPs) are classes of
active agents. See, e.g., Balaban, N., et al., "Regulation of
Staphylococcus aureus pathogenesis via target of RNAIII-activating
Protein (TRAP)," J. Biol Chem., 2001 Jan. 26; 276(4): 2658-67,
which is incorporated by reference herein in its entirety.
[0161] When an active agent of the present invention is acidic,
salts may be prepared from pharmaceutically acceptable non-toxic
bases. Salts derived from all stable forms of inorganic bases
include aluminum, ammonium, calcium, copper, iron, lithium,
magnesium, manganese, potassium, sodium, zinc, etc. In one
embodiment, the salt includes ammonium, calcium, magnesium,
potassium, or a sodium salt. Salts derived from pharmaceutically
acceptable organic non-toxic bases include salts of primary,
secondary, and tertiary amines, substituted amines including
naturally occurring substituted amines, cyclic amines and basic
ion-exchange resins such as arginine, betaine, caffeine, choline,
N,N dibenzylethylenediamine, diethylamine, 2-diethylaminoethanol,
2-dimethyl-aminoethanol, ethanolamine, ethylenediamine,
N-ethylmorpholine, N-ethylpiperidine, glucamine, glucosamine,
histidine, isopropylamine, lysine, methyl-glucosamine, morpholine,
piperazine, piperidine, polyamine resins, procaine, purine,
theobromine, triethylamine, trimethylamine, tripropylamine,
etc.
[0162] When an active agent of the present invention is basic,
salts may be prepared from pharmaceutically acceptable non-toxic
acids. Such acids include acetic, benzene-sulfonic, benzoic,
camphorsulfonic, citric, ethane-sulfonic, fumaric, gluconic,
glutamic, hydrobromic, hydrochloric, isethionic, lactic, maleic,
mandelic, methane-sulfonic, mucic, nitric, pamoic, pantothenic,
phosphoric, succinic, sulfuric, tartaric, p-toluenesulfonic, etc.
In one embodiment, the acid includes citric, hydrobromic, maleic,
phosphoric, sulfuric, and/or tartaric acids.
[0163] Although some active agents can be attached directly to the
coating/derivatized surface, most active agents according to the
present invention can often be attached to the coatings/derivatized
surfaces of the invention via .alpha.,.omega.-difunctional linkers
or spacers, which will often be tailored to the particular active
agent(s) used. It is noted that the .alpha.- and .omega.-functional
groups of the linkers/spacers can be similar or different, and
often are different particularly where release of the active
agent(s) is(are) intended (e.g., in vivo). Such attachment (and
release) of active agents can be effected by covalent bonding
(cleaving), ionic bonding (dissociation), physical transitions of
state such as crystallization (melting) or liquid crystalline-type
ordering (disordering), hydrogen bonding (dissociation), van der
Waals interactions (repulsions), or the like, or any combination
thereof. The linkers/spacers can be of relatively small molecular
weight (e.g., less than about 200 g/mol), relatively intermediate
molecular weight (e.g., from about 200 to about 2000 g/mol),
relatively large molecular weight (e.g., more than about 2000
g/mol), or some combination thereof. Particularly when the
linkers/spacers are of relatively intermediate and/or relatively
large molecular weight, they can include, but are not limited to,
oligomers, polymers, and/or copolymers described above as bioactive
moieties or biodegradeable polymers; additionally or alternately,
the linkers/spacers can include, but are not limited to, oligomers,
polymers, and/or copolymers having one or more of the following
types of repeat units: urethanes, ureas, ethers, ketones, esters,
amines, carbonates, amides, saccharides, or the like, or
combinations thereof.
[0164] In other embodiments, polyfunctional linkers/spacers can be
used to attach active agents to the coatings/derivatized surfaces
according to the invention. Such poly-functional linkers/spacers
can include, but are not limited to, oligomers, polymers, and/or
copolymers that are branched, hyperbranched, dendritic,
star-shaped, brushes, combs, block, multiblock, gels, hydrogels, or
the like, or any combination thereof.
Characteristics of Coatings and Derivatized Surfaces
[0165] The coatings and derivatized surfaces according to the
invention are typically present on synthesized, native and/or
passivated oxide surfaces. In some cases, these surfaces have
relatively low surface --OH content. For example, as mentioned
above, titanium, silicon, and titanium alloys (such as Ti-6Al-4V)
typically exhibit a surface --OH content of .about.0.15-0.25
nmol/cm.sup.2 --OH groups. The surface --OH content of titanium,
silicon, titanium alloys and other implantable materials may be
significantly lower, for example, .about.0.10 nmol/cm.sup.2--OH
groups, or for example .about.0.05 nmol/cm.sup.2--OH groups
depending upon the manufacturing environment or manufacturing
process. Such manufacturing processes are known to one of skill in
the art and include heating, anoxic heating or acid etching. In
some cases, substantially all surface --OH groups can be removed.
However, in some embodiments, it may be useful to use synthesized,
native and/or passivated oxides that exhibit surface --OH contents
of .ltoreq.0.5 nmol/cm.sup.2--OH groups, for example of .ltoreq.0.4
nmol/cm.sup.2--OH groups, for example of .ltoreq.0.3
nmol/cm.sup.2--OH groups, before coating and/or derivatization.
[0166] The phosphorous based coatings and derivatized surfaces
according to the invention may be "functionalized" or
"unfunctionalized." As used herein, the term "functionalized" means
that the portion of the molecules remote to the end covalently
bonded to an oxide surface has a terminal group that contains a
usually chemically reactive moiety (e.g., an --OH group, an
.omega.-phosphate group, an .omega.-phosphonate group, a --COOH
group, an amino group, a mercapto group, or the like, an
unsaturated hydrocarbon group such as --CH.dbd.CH.sub.2 or the
like). As used herein, the term "unfunctionalized" means that the
portion of the molecules remote to the end covalently bonded to an
oxide surface has a terminal group that contains a
usually-non-reactive moiety (e.g., a halocarbon group such as
--CF.sub.2CF.sub.3 or --CH.sub.2CF.sub.3 or the like; a saturated
hydrocarbon group such as --CH.sub.2CH.sub.3 or the like; or the
like). The term "remote to" includes the functional groups being at
any position removed from the phosphate or phosphonate moieties,
including functional groups at a position omega to said
moieties.
[0167] With respect to a layer, the term "functionalized" refers to
the external surface of that layer, or the portion of that layer
not being covalently bonded to an oxide surface, that exhibits a
surface-containing, chemically reactive group. With respect to a
layer, the term "unfunctionalized" refers to the external surface
of that layer, or the portion of that layer not covalently bonded
to an oxide surface, that exhibits a surface-containing,
usually-non-reactive group.
[0168] In some embodiments where the phosphorus-based coating is
functionalized, the surface functional group density (e.g., the
surface density of hydroxyl groups, phosphate groups, phosphonate
groups, thiol groups, carboxylic acid groups, carboxylate groups,
etc.) can be more than about 0.1 nmol/cm.sup.2, alternatively more
than about 0.25 nmol/cm.sup.2, also more than 0.3 nmol/cm.sup.2,
also more than about 0.4 nmol/cm.sup.2, for example more than about
0.5 nmol/cm.sup.2, alternately more than about 0.8 nmol/cm.sup.2 or
for example more than about 1.0 nmol/cm.sup.2. Additionally or
alternately, also in embodiments where the phosphorus-based coating
is functionalized, the surface functional group density can be at
least great than or equal to, at least about 1.3 times, at least
about 1.5 times, for example at least about 2 times, or for example
at least about 3 times the surface hydroxyl group density of an
oxide surface of an implantable substrate. In other embodiments
where the surface hydroxyl group density of an oxide surface of an
implantable substrate is reduced by manufacturing or processing,
the surface functional group density can be at least about 5 times,
for example at least about 10 times, for example at least about 25
times, or for example at least about 100 times the surface hydroxyl
group density of an oxide surface of an implantable substrate.
[0169] In some embodiments where the phosphorus-based coating is
unfunctionalized, the surface graft/packing density can be more
than about 0.1 nmol/cm.sup.2, alternatively more than about 0.25
nmol/cm.sup.2, for example more than about 0.3 nmol/cm.sup.2, or
for example more than about 0.5 nmol/cm.sup.2, alternatively more
than about 0.8 nmol/cm.sup.2, at least about 1 nmol/cm.sup.2, for
example at least about 1.2 nmol/cm.sup.2, alternately at least
about 1.5 nmol/cm.sup.2. Also in embodiments where the
phosphorus-based coating is unfunctionalized, the surface
graft/packing density can be at least great than or equal, or for
example about 1.3 times, or for example about 1.5 times, at least
about 2 times, for example at least about 2.5 times, the surface
hydroxyl group density of an oxide surface of an implantable
substrate. In other embodiments where the surface hydroxyl group
density of an oxide surface of an implantable substrate is reduced
by manufacturing or processing, the surface functional group
density can be at least about 5 times, for example at least about
10 times, or for example at least about 25 times, or for example at
least about 100 times the surface hydroxyl group density of an
oxide surface of an implantable substrate.
[0170] In some embodiments where the phosphorus-based coating is
functionalized, the surface phosphorus-containing group density
(e.g., the surface density of phosphate and/or phosphonate groups)
can be more than about 0.1 nmol/cm.sup.2, for example more than
about 0.25 nmol/cm.sup.2, more than 0.3 nmol/cm.sup.2, also more
than about 0.4 nmol/cm.sup.2, for example more than about 0.5
nmol/cm.sup.2, alternately more than about 0.8 nmol/cm.sup.2, at
least about 1 nmol/cm.sup.2, or about 1.5 nmol/cm.sup.2.
Additionally or alternately, also in embodiments where the
phosphorus-based coating is functionalized, the surface functional
group density can be greater than or equal to, or at least about
1.3 times, at least about 1.5 times, for example at least about 2
times, alternately at least about 2.5 times, the surface hydroxyl
group density of an oxide surface of the substrate.
[0171] The phosphorus-based coating and/or derivatized layer can
have a thickness of less than about 10 nm, less than about 5 nm,
for example not more than about 3 nm, alternately not more than
about 2.5 nm or not more than about 1.5 nm or not more than about 1
nm. In other embodiments, the phosphorus-based coating and/or
derivatized layer can have a thickness of less than about 100 nm,
or for example, less than about 50 nm, alternatively less than
about 25 nm or less than about 15 nm.
[0172] In some embodiments, when the phosphorus-based coating
and/or derivatized layer is bound to an oxide surface of an
implantable substrate, the coating-oxide surface bond exhibits a
Mode I (shear) strength of at least about 20 MPa, at least about 40
MPa, for example at least about 50 MPa, alternately at least about
60 Mpa or for example at least about 70 MPa.
[0173] In some embodiments, when the phosphorus-based coating
and/or derivatized layer is bound to an oxide surface of an
implantable substrate, the coating-oxide surface bond exhibits a
tensile strength of at least about 60 MPa, or at least about 80
Mpa.
[0174] In one embodiment, the phosphorus-based coating is
covalently bonded to an oxide surface of an implantable substrate
and the phosphorus-based coating exhibits a surface
phosphorus-containing group density of at least about 0.1
nmol/cm.sup.2 and a thickness of less than about 10 nm.
[0175] As used herein, the term "implantable substrate" means any
material with an oxide surface that may be totally or partially
implanted into a human or animal body includeing, but not limited
to titanium and its alloys, cobalt chromium and its alloys,
stainless steel, alloys of stainless steel and nitinol. As used
herein, the term "an oxide surface of an implantable substrate"
means the entire oxide surface of an implantable substrate or one
or more oxide surfaces of an implantable substrate. As used herein,
the term "an oxide surface of an implantable device" means the
entire oxide surface of an implantable device, or one or more oxide
surfaces of an implantable device or one or more oxide surfaces of
one or more implantable devices.
[0176] In another embodiment, the phosphorus-based coating and/or
derivatized layer is covalently bonded to an oxide surface of an
implantable substrate exhibiting a surface hydroxyl group density
of not more than about 0.4 nmol/cm.sup.2, and the phosphorus-based
coating exhibits a surface phosphorus-containing group density of
at least about 0.5 nmol/cm.sup.2, a surface phosphorus-containing
group density of at least about 1.3 times the surface hydroxyl
group density of an oxide surface of an implantable substrate, and
a thickness of less than about 5 nm.
[0177] In one embodiment, the phosphorus-based coating and/or
derivatized layer is covalently bonded to an oxide surface of an
implantable substrate exhibiting a surface hydroxyl group density
of not more than about 0.3 nmol/cm.sup.2, and the phosphorus-based
coating exhibits a surface phosphorus-containing group density of
at least about 1 nmol/cm.sup.2, a surface phosphorus-containing
group density of at least about 2 times the surface hydroxyl group
density of an oxide surface of an implantable substrate, and a
thickness of not more than about 2 nm.
[0178] In some embodiments where the phosphorus-based coating is
functionalized, particularly when the functionality is a hydroxyl
functionality (e.g., when 11-hydroxy-undecylphosphonic acid is
covalently bonded to a metal/metal oxide substrate such as
titanium), the coating and/or derivatized layer may exhibit cell
non-attraction or cell resistance. As used herein, the terms "cell
resistance" and "cell resistant," with respect to surfaces, should
be understood to indicate the substantial absence of human fetal
osteoblasts adherent to the surface and/or of actin filaments in
human fetal osteoblasts that are adherent to the surface, when
human fetal osteoblasts are exposed to surface for not more than 3
days, for example not more than 2 days, for example at least 90
minutes, also more than at least 12 hours, for example at least 24
hours.
[0179] In some embodiments where the phosphorus-based coating is
functionalized, particularly when the functionality is a hydroxyl
functionality (e.g., when 11-hydroxy-undecylphosphonic acid is
bonded to a metal/metal oxide substrate such as titanium), the
phosphorus-based coating and/or functionalized coating may be
oxidatively stable. As used herein, the terms "oxidatively stable"
and "oxidative stability," with respect to surfaces, should be
understood to indicate that the surfaces exhibit any one or more of
the following: (1) a surface content/functionality/loading after
exposure for about 3 hours to 14/14/80 milliMolar
TiCl.sub.3/EDTA/H.sub.2O.sub.2 oxidant of at least 80%, for example
at least 90%, for example at least 95% of the surface
content/functionality/loading before exposure; (2) a normalized
FTIR peak area from about 3000 cm.sup.-1 to about 2750 cm.sup.-1
and having a peak at about 2920-2910 cm.sup.-1 after exposure for
about 3 hours to 14/14/80 milliMolar TiCl.sub.3/EDTA/H.sub.2O.sub.2
oxidant that differs by not more than about 20%, also not more than
about 15%, for example not more than about 10% or not more than
about 5%, as compared to the normalized FTIR peak area in the same
region before exposure; (3) a normalized FTIR peak area from about
1110 cm.sup.-1 to about 1050 cm.sup.-1 and having a peak at about
1090 cm.sup.-1 after exposure for about 3 hours to 14/14/80
milliMolar TiCl.sub.3/EDTA/H.sub.2O.sub.2 oxidant that differs by
not more than about 15%, not more than about 10%, for example not
more than about 5% or not more than about 2%, as compared to the
normalized FTIR peak area in the same region before exposure; (4)
an average (of at least five values) advancing and/or receding
contact angle after exposure for about 3 hours to 14/14/80
milliMolar TiCl.sub.3/EDTA/H.sub.2O.sub.2 oxidant that differs by
not more than about 15.degree., not more than about 10.degree., for
example not more than about 5.degree., as compared to the average
advancing and/or receding contact angle before exposure (the
advancing or receding contact angle may be measured with deionized
water; however, other liquids may be used, e.g.,
11-hydroxyundecylphosphonic acid, 1,6-diphosphonatohexane,
1,12-diphosphonatododecane, octadecylphosphonic acid, or
hexafluoroisopropanol)
[0180] Cyclic RGD peptides can interact with integrins more
effectively than their linear analogues possibly due to an increase
in conformational stability which leads to an enhancement in the
preferred three-dimensional structure for receptor interactions.
For instance, cyclic (RGDFV-)exhibits over 100 times greater
specificity towards .alpha..sub.v.beta..sub.3 integrins than linear
GRGDSPK.
[0181] Additionally, it has been established that RGD peptide
containing sequences are susceptible to chemical degradation at the
aspartic acid residue which leads to loss of biological activity.
It is believed that the rate of degradation is dependent upon the
flexibility of the peptide sequence, which has generated interest
in more rigid conformations, such as cyclic species. It has been
shown in solution by HPLC that (cyclo)-1,6
acetyl-CRGDF-penicillamine-NH.sub.2 was 30 times more stable than
linear RGDF at pH 7. Therefore, it would be of interest to use
cyclic RGD containing species to both enhance integrin binding as
well as to increase enzymatic stability in vivo.
[0182] While the cyclic conformation of RGD does increase the
specific binding to .alpha..sub.v.beta..sub.3 integrins, there
remains an affinity for other integrins which limits overall
selectivity. It may be of interest to circumvent the selectivity
issue by speeding the colonization of the implant surface which
fosters the proper environment for osteoprogenitor cells. This
could be achieved by creating mixed films of cyclic RGD (integrins)
and saccharides that would create an environment that mimics the
ECM of the cells. A polysaccharide-modified surface has been shown
to attract roughly 200-fold more osteoblasts than untreated glass
at an immersion time of 15 minutes. It could be of great benefit to
couple the integrin-binding peptide sequence cyclic-RGD with the
polysaccharide films in order to achieve fast colonization of the
implant surface which could facilitate and speed healing.
[0183] In order to create these mixed-film systems, phosphonic
acids films could be made on the oxide of interest through standard
procedures. Then standard coupling techniques could be employed to
bind mixed films of cyclic RGD and heparin saccharide derivatives.
For example, examples of and methods for peptide coupling to
implant surfaces can be found, e.g., in U.S. Pat. No. 6,280,760,
the contents of which are hereby incorporated by reference.
[0184] Surprisingly, it has been found that linear RGD peptide
containing sequences have higher than expected specificity, binding
strength and enzymatic stability when attached to the coatings of
the present invention.
[0185] In some embodiments where the phosphorus-based coating is
functionalized (e.g., when hydroxyundecylphosphonic acid is bonded
to an oxide surface of silicon), the coating and/or derivatized
layer can demonstrate excellent current blockage properties.
Implantable Devices
[0186] The coatings and derivatized surfaces according to the
invention can further be applied to a variety of implantable
devices. Although any device with at least one oxide surface may
comprise a coating of the invention, general classes of suitable
implantable devices include, but are not limited to, vascular
devices such as grafts, stents, stent grafts, catheters, valves,
artificial hearts, and heart assist devices such as pacemakers;
orthopedic devices such as joint implants, fracture repair devices,
and artificial tendons; dental devices such as dental implants and
fracture repair devices; drug delivery devices including drug
infusion devices; ophthalmic devices and glaucoma drain shunts;
urological devices such as penile, sphincter, urethral, bladder,
and renal devices; and other catheters, synthetic prostheses such
as breast prostheses and artificial organs; neurostimulation,
electrostimulation and electrosensing devices including electrical
stimulation leads, brain tissue stimulators, central nerve
stimulators, peripheral nerve stimulators, spinal cord nerve
stimulators and sacral nerve stimulators. Other suitable biomedical
devices include dialysis tubing and membranes, blood oxygenator
tubing and membranes, blood bags, sutures, membranes, cell culture
devices, chromatographic support materials, biosensors, anastomotic
connector, surgical instrument, angioplasty balloon, wound drain,
shunt, tubing, urethral insert, pellet, blood oxygenator, pump, and
the like.
[0187] Exemplary implantable devices that may comprise one or more
coated surfaces of the invention are listed in Table 2 below (all
references as set forth below are herein incorporated by reference
in their entirety for all purposes). For instance, any device
classified within any of the following statutory classifications
may comprise one or more coated surfaces of the invention and is
herein incorporated by reference for all purposes. TABLE-US-00002
TABLE 2 Exemplary Implantable Orthopedic and Dental Devices
Device(s) Subtype Examples References Implantable, All types See,
e.g. 21 CFR .sctn. 888.3300 artificial hip joint (2005) prosthesis
Implantable, Constrained or semi- See 21 CFR .sctn. 888.3300, 3330,
artificial hip joint constrained 3353, 3358 (2005) prosthesis
Implantable, Uncemented femoral stem 21 CFR .sctn. 888.3300 (2005)
artificial hip joint and/or uncemented Hip joint metal/metal semi-
prosthesis acetabular cup constrained, with an uncemented
acetabular component, prosthesis 21 CFR .sctn. 888.3353 (2005) Hip
joint metal/ceramic/polymer semi-constrained cemented or nonporous
uncemented prosthesis. 21 CFR .sctn. 888.3358 (2005) Hip joint
metal/polymer/metal semi-constrained porous-coated uncemented
prosthesis Implantable, Metal ball on femoral stem 21 CFR .sctn.
888.3300 (2005) artificial hip joint to metal acetabular cup Hip
joint metal/metal semi- prosthesis constrained, with an uncemented
acetabular component, prosthesis 21 CFR .sctn. 888.3358 (2005) "Hip
joint metal/polymer/metal semi-constrained porous-coated uncemented
prosthesis." Implantable, Metal ball on femoral stem 21 CFR .sctn.
888.3390 (2005) artificial hip joint to polymer lined "Hip joint
femoral (hemi-hip) prosthesis acetabular cup metal/polymer cemented
or uncemented prosthesis." 21 CFR .sctn. 888.3358 (2005) "Hip joint
metal/polymer/metal semi-constrained porous-coated uncemented
prosthesis." Implantable, Metal ball on femoral stem See, e.g. 21
CFR .sctn. 888.3353 artificial hip joint to ceramic lined (2005)
prosthesis acetabular cup Hip joint metal/ceramic/polymer
semi-constrained cemented or nonporous uncemented prosthesis.
Implantable, Ceramic ball on femoral See, e.g. 21 CFR .sctn.
888.3353 artificial hip joint stem to ceramic or (2005) prosthesis
polymer lined acetabular Hip joint metal/ceramic/polymer cup
semi-constrained cemented or nonporous uncemented prosthesis.
Implantable, Hemi-hip 21 CFR .sctn. 888.3360 (2005) artificial hip
joint Hip joint femoral (hemi-hip) prosthesis metallic cemented or
uncemented prosthesis. 21 CFR .sctn. 888.3390 (2005) Hip joint
femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis.
Implantable hip 21 CFR .sctn. 888.3400 (2005) resurfacing Hip joint
femoral (hemi-hip) prosthesis metallic resurfacing prosthesis An
acetabular Acetabular cup, component of an acetabular ring or
implantable, acetabular cage artificial hip joint An acetabular
Uncemented. Interior See e.g., 21 CFR .sctn. 888.3300 component of
an surface comprising metal, (2005) implantable, polymer, ceramic.
Hip joint metal/metal semi- artificial hip joint constrained, with
an uncemented acetabular component, prosthesis Implantable, All
types artificial knee joint prosthesis Implantable, Uncemented, 21
CFR .sctn. 888.3535 (2005) artificial knee joint metal/polymer or
Knee joint femorotibial (uni- prosthesis metal/metal,
compartmental) metal/polymer porous-coated uncemented prosthesis 21
CFR .sctn. 888.3550 (2005) Knee joint patellofemorotibial
polymer/metal/metal constrained cemented prosthesis 21 CFR .sctn.
888.3565 (2005) Knee joint patellofemorotibial metal/polymer
porous-coated uncemented prosthesis Implantable, Uncemented femoral
21 CFR .sctn. 888.3570 (2005) artificial knee joint component Knee
joint femoral (hemi-knee) prosthesis metallic uncemented prosthesis
Implantable, Uncemented patellar 21 CFR .sctn. 888.3580 (2005)
artificial knee joint component Knee joint patellar (hemi-knee)
prosthesis metallic resurfacing uncemented prosthesis Implantable,
Uncemented tibial 21 CFR .sctn. 888.3590 (2005) artificial knee
joint component Knee joint tibial (hemi-knee) prosthesis metallic
resurfacing uncemented prosthesis Implantable, All types 21 CFR
.sctn. 888.3670 (2005) artificial shoulder Shoulder joint
metal/polymer/metal joint prosthesis nonconstrained or semi-
constrained Implantable, Uncemented 21 CFR .sctn. 888.3670 (2005)
artificial shoulder Shoulder joint metal/polymer/metal joint
prosthesis nonconstrained or semi- constrained Implantable, Glenoid
component (hemi- artificial shoulder shoulder) joint prosthesis
Implantable, Humeral component 21 CFR .sctn. 888.3690 (2005)
artificial shoulder (hemi-shoulder) Shoulder joint humeral (hemi-
joint prosthesis shoulder) metallic uncemented prosthesis
Implantable Pedicle screw system 21 CFR .sctn. 888.3070 (2005)
artificial spine Pedicle screw system prostheses Implantable Spinal
interlaminal fixation 21 CFR .sctn. 888.3050 (2005) artificial
spine orthosis Spinal interlaminal fixation orthosis prostheses
Implantable Spinal intervertebral body 21 CFR .sctn. 888.3060
(2005) artificial spine fixation orthosis Spinal intervertebral
body fixation prostheses orthosis Implantable All types 21 CFR
.sctn. 888.3150 (2005) artificial elbow joint Elbow joint
metal/polymer prosthesis constrained cemented prosthesis 21 CFR
.sctn. 888.3160 (2005) Elbow joint metal/polymer semi- constrained
cemented prosthesis Implantable Humeral Stem, 21 CFR .sctn.
888.3180 (2005) artificial elbow joint uncemented Elbow joint
humeral (hemi-elbow) prosthesis metallic uncemented prosthesis
Implantable Ulnar Stem, uncemented artificial elbow joint
prosthesis Implantable All types artificial wrist joint prosthesis
Implantable Uncemented 21 CFR .sctn. 888.3790 (2005) artificial
wrist joint Wrist joint metal constrained prosthesis cemented
prosthesis Implantable All types artificial ankle joint prosthesis
Implantable Uncemented, metal/metal No FDA definition for
uncemented artificial ankle joint or metal/composite or ankle
joints. See 21 CFR .sctn. prosthesis metal/polymer 888.3100-3120
(2005). Implantable Semi-constrained, 21 CFR .sctn. 888.3100 (2005)
artificial ankle joint metal/composite or Ankle joint
metal/composite semi- prosthesis metal/polymer constrained cemented
prosthesis 21 CFR .sctn. 888.3110 (2005) Ankle joint metal/polymer
semi- constrained cemented prosthesis Implantable Uncemented, semi-
No FDA definition for uncemented artificial ankle joint constrained
or non- ankle joints. See 21 CFR .sctn. prosthesis constrained
888.3100-3120 (2005). Implantable Non-constrained 21 CFR .sctn.
888.3120 (2005). artificial ankle joint Ankle joint metal/polymer
non- prosthesis constrained cemented prosthesis. Implantable All
types artificial finger joint prosthesis Implantable Uncemented,
constrained 21 CFR .sctn. 888.3300 (2005) artificial finger joint
or unconstrained Finger joint metal/metal prosthesis constrained
uncemented prosthesis. Implantable All types artificial toe
prosthesis Implantable Uncemented 21 CFR .sctn. 888.3720 (2005)
artificial toe Toe joint polymer constrained prosthesis prosthesis
21 CFR .sctn. 888.3730 (2005) Toe joint phalangeal (hemi-toe)
polymer prosthesis Orthopedic Rods and pins 21 CFR .sctn. 888.3720
(2005) devices for fracture Intramedullary fixation rod repair,
bone fusion, fixation Orthopedic Pins, nails, screws, 21 CFR .sctn.
888.3730 (2005) devices for fracture staples, hooks, cable grip
Single/Multiple component metallic repair, bone bone fixation
appliances and fusion, fixation accessories Orthopedic Smooth or
threaded 21 CFR .sctn. 888.3740 (2005) devices for fracture
metallic bone fixation Smooth or threaded metallic bone repair,
bone fastener fixation fastener fusion, fixation Orthopedic Bone
plate devices for fracture repair, bone fusion, fixation and trauma
treatment Orthopedic Metal external fixator pin; devices for
fracture metal external fixator repair, bone screw fusion, fixation
and trauma treatment Orthopedic Bone screw, canulated or devices
for fracture uncanulated repair, bone fusion, fixation and trauma
treatment Orthopedic Bone nails, straight or devices for fracture
curved repair, bone fusion, fixation and trauma treatment
Orthopedic devices for limb lengthening Dental implant Endosseous
dental 21 CFR .sctn. 888.3640 (2005) implant Endosseous dental
implant Dental implant Endosseous dental 21 CFR .sctn. 888.3630
(2005) implant abutment Endosseous dental implant abutment Dental
implant Subperiosteal implant 21 CFR .sctn. 888.3645 (2005)
material Subperiosteal implant material
EXAMPLES
Examples 1-3
[0188] For the following Examples 1-3, ethanol (reagent grade) was
obtained from Aldrich Chemical and used as received.
11-Hydroxyundecylphosphonic acid (a linear, 11-carbon-atom
difunctional phosphonic acid having an .omega.-hydroxyl functional
group to the phosphonic acid) was synthesized according to
published procedures. Disks were cut from titanium Ti-6Al-4V rod
(1' in diameter, obtained from Goodfellow, Inc.) and prepared for
use by sanding, followed by cleaning with methanol. The disks were
dried for at least an hour before use, and stored in an oven at
200.degree. C.
[0189] Samples were analyzed using either a Nicolet 730 FT-IR
equipped with a Spectra Tech diffuse reflectance (DRIFT) attachment
or a MIDAC Illuminator equipped with a Surface Optics specular
reflectance head. When the Nicolet was used for analysis, infrared
experiments were performed using a glancing angle attachment, a
Variable Angle Specular Reflectance Model 500, obtained from
Spectra Tech. The angle between the surface normal and the incident
beam was approximately 87.degree.. For both instruments, samples
were purged with nitrogen for half an hour to reduce the amount of
water on the surface, and 1,000 scans were collected to obtain a
reasonable signal to noise ratio. All spectra obtained were as a
ratio against a spectrum of a clean native oxide surface.
Example 1
Application of a Coating Layer
[0190] A white cotton swatch of commercial textile measuring 2'
square was prepared as a carrier by rinsing in distilled water and
drying in air. A 1.0 millimolar coating solution of
11-Hydroxyundecylphosphonic acid was prepared by dissolving 0.1 mM
of the acid in 100 ml of ethanol. About 50 ml of the solution was
placed in a shallow dish and the carrier was placed into the
solution and saturated with it. The carrier was then removed from
the solution and permitted to remain in air until it was visibly
dry (overnight). Thus prepared, the carrier with containing a
coating composition comprising 11-Hydroxyundecylphosphonic acid was
placed over a titanium disk prepared as described above. A consumer
cloth iron with a Teflon.TM.-coated heating platen (Black &
Decker) set for cotton cloth (no steam) was placed on top of the
assembly for a period of 5 minutes. At the end of the heating
period the iron was removed and the oxide substrate (titanium disk)
was allowed to cool in the ambient air. The disks were sonicated in
ethanol and rinsed with copious amounts of ethanol and dried in
air.
[0191] Infrared examination of the area covered by the carrier by
the procedure described above showed the presence of a coating
layer comprising bound 11-hydroxyundecylphosphonate. Integration of
the signal strength indicated that the films comprised about 10
times the amount of material typically observed by treating similar
surfaces directly with a similar coating solution. Repeated
rinising and sonication did not result in a diminution of the
signal, indicating that the coating layer was well bound to the
surface.
[0192] Visual inspection of the coupon shows that a coating layer
is applied to the coupon only where contact was made with the
carrier.
Example 2
Deposition of a Coating Layer on a Metal Oxide Coated Plastic
[0193] A sheet of antireflective coated polyethylene oxide
terephthalate (PET) which has a top layer of silicon dioxide will
be obtained from Bekaert Specialty Films. Application of a cotton
carrier prepared with a coating composition, as described above for
Example 1, in accordance with the treatment procedure described
above for Example 1 will be found to provide an
11-hydroxyundecylphosphonate coating to the antireflective coated
plastic.
Example 3
Derivatization of the Surface with an Adhesive Layer
[0194] It will be found that the coating layer prepared in Example
1 above (a phosphonate coating derived from
11-hydroxyundecylphosphonic acid) can be further derivatized with
an epoxy linking group by applying a film of Cytec Fiberite FM
100.TM. epoxy adhesive to the surface. Before the adhesive cured, a
second titanium coupon prepared according to Example 1 can be
placed in contact with the epoxy such that a lap joint is formed.
When the epoxy is cured under ambient conditions, it will be found
that the strength of the lap joint, when compared with
substantially similar assemblies prepared from equivalent titanium
coupons which have not received a coating layer by the process of
the invention, is considerably lower. It will be found if these
samples are compared according to ASTM testing standard F1044-99,
that on average, the joint between the uncoated coupons failed at
2/3 the pressure which must be applied to fail the joint between
the coated coupons.
Examples 4-33 and Comparative Examples 1-5
[0195] Example films of phosphonates and phosphates were prepared
on coupons of metal foil or on disks of metal cut from billet. As
noted, samples were prepared in some cases by dip coating the
coupon in a bulk solution of the coating moiety and in others by
aerosol application of the solution to a surface of the coupon.
Aerosol application of monofunctional phosphonic acids was carried
out by dissolving the acid in tetrahydrofuran (THF) or methanol,
spraying the acid solution onto the target oxide surface. As noted,
aerosol application was carried out either in the ambient
environment by spraying a solution of the acid from a pump-spray
bottle, or with the target surface residing in a standard nitrogen
charged glove box.
[0196] The solvent was allowed to evaporate from the sample either
with gentle heating and/or a gas current, for example, nitrogen
flowing over the surface, or left to evaporate to the ambient
environment by spraying in a solution of the acid from a pump-spray
bottle. Where noted, solvent evaporation was carried out in the
ambient environment or in an inert atmosphere glove box. For
application of difunctional phosphonic acids, two procedures were
followed. In the first procedure, a THF solution of the phosphonic
acid was applied to the target oxide surface while its substrate
rested in the ambient atmosphere on a hot plate to aid evaporation
of the solvent. The treated oxide surface and substrate were then
transferred to a 120.degree. C. oven and annealed at oven
temperature for up to 48 hours. Following removal from the oven and
cooling, the derivatized surface was rinsed with dry, distilled THF
to ensure only bound species remained. The residue of rinsing
solvent remaining on the coupon was evaporated and the coupon
surface was subjected to analysis.
[0197] In the second procedure, the substrate was placed in a
vessel containing a quantity of acid solution, the solvent was
evaporated with the substrate in place and the substrate was
annealed in an oven to react the phosphoric acid solvent to the
surface with the native oxide.
[0198] In the formation of phosphate coatings, spray or dip
procedures, described above, were employed to pre-coat the native
oxide surface with phosphoric acid solution. Where noted,
phosphoric acid was used as either a THF or aqueous solution.
[0199] Films were analyzed using a quartz microbalance and by FTIR
spectroscopy, X-ray powder diffraction spectroscopy, contact angle
measurement and "peel testing". The following procedures were
used.
Quartz Crystal Microbalance (QCM)
[0200] The QCM technique allows accurate, gravimetric determination
of mass changes on an electrode which is deposited on a
piezoelectric quartz crystal. It is, thus, ideal to monitor surface
reactions of target metals when they are used as such electrodes:
the QCM oscillates at a resonant frequency which is determined by
the cut and mass of the crystal, and, just as for a classical
oscillator, changes in electrode mass result in changes in crystal
resonant frequency. Since our experiments necessitated detaching
active crystals from the QCM oscillator for extended periods of
time followed by reattachment, control measurements had to be made
of reference crystals which were subjected to similar handling, but
without surface treatment. Up to three different reference crystals
(prepared in different batches) were used as received to calibrate
the QCM. Careful handling of the active and reference crystals was
observed to prevent unacceptably large (>10 Hz) frequency change
from the initial value, during an experimental run. To ensure that
monolayer coverage (at most) occurred on Ti surface, phosphonic
acid-based films were subjected to copious rinsing followed by
evacuation (.ltoreq.10.sup.-2 Torr) until a constant crystal
frequency was established (within experimental noise levels of
.+-.2 Hz).
[0201] Piezoelectric quarts crystals (International Crystal
Manufacturers [ICM]; AT-cut, 1000 .ANG. Ti electrodes, 10 MHz,
overtone polished, 0.201 in. electrode diameter) were used for film
deposition and as references. The QCM circuitry was allowed to
stabilize for 30 min. after start-up, before experimental
measurements were made. In each experimental run, the fundamental
frequency (f.sub.o) of an unreacted crystal was measured. The
crystal was then removed from its holder, aerosol sprayed (on both
electrodes) with a solution of the phosphorous-based acid and
heated at 120.degree. C. for 3 days. A new frequency (f.sub.c) was
then measured. The crystal was then subjected to rinsing followed
by evacuation (.ltoreq.10.sup.-2 Torr) until a constant frequency
was measured (.+-.2 Hz), assumed to be a monolayer coverage of the
Ti electrodes. The difference between the monolayer-loaded and the
unreacted crystal was then related to the amount of material
chemisorbed on the Ti electrode active area.
[0202] The quartz crystal microbalance (QCM) was driven by a
home-built Clapp oscillator and powered by a Hewlett Packard 6234A
Dual Output Power Supply. The frequency of the crystal was measured
using a Hewlett Packard 5334B Universal Counter and a record of the
frequencies was tracked using a laboratory computer. A change in
the observed frequency indicated a change in the mass of the
crystal. To ensure that all the frequency changes were attributable
to the deposition of the reactants, the frequency of the crystal
was monitored before and after exposure to reactants. See, e.g.,
U.S. Provisional Application No. 60/684,159.
X-Ray Powder Diffraction
[0203] Samples were analyzed by X-ray diffraction using a Rigaku
Miniflex spectrometer with CuK.about.radiation and a Zn filter.
Samples were scanned for 2.theta.=8-55.degree. (0.04.degree./2
sec). Data were analyzed and refined and matched with that of known
species using Jade 3.0 Pattern Processing for Windows. Samples were
placed on glass microscope slides using Dow Corning Vacuum Grease,
and were placed in an appropriate holder.
Infrared Spectroscopy
[0204] Samples were analyzed using either a Nicolet 730 FT-IR
equipped with a Spectra Tech diffuse reflectance (DRIFT) attachment
or a MIDAC Illuminator equipped with a Surface Optics specular
reflectance head. When the Nicolet was used for analysis, infrared
experiments were performed using a glancing angle attachment, a
Variable Angle Specular Reflectance Model 500, obtained from
Spectra Tech. The angle between the surface normal and the incident
beam was approximately 87.degree.. For both instruments, samples
were purged with nitrogen for half an hour to reduce the amount of
water on the surface, and 1,000 scans were collected to obtain a
reasonable signal to noise ratio. All spectra obtained were ratioed
against a spectrum of a clean native oxide surface.
"Peel-Testing"
[0205] Coupons which had been treated were rinsed several times
with deposition solvent and, where appropriate, ethanol and/or
water, to remove soluble residues. A piece of tape (e.g., 3M red
Scotch.TM. "650" tape or Scotch Masking Tape #234; 37 oz./in.
adhesion to steel) was adhered to the derivatized surface of the
solvent washed foil sample and quickly removed. The freshly
"peeled" coupon was then analyzed again by DRIFT spectroscopy.
Contact Angle Measurement
[0206] Contact angles were measured at room temperature and ambient
conditions on a Tantec Contact Angle Meter CAM-F1.
[0207] All reagents were obtained from Aldrich Chemical unless
otherwise noted. Propionic acid (99+percent), octanoic acid
(99.5+percent), and stearic acid (99.5+percent) were used as
received, 11-phosphonoundecanoic acid (an 11 carbon atom, linear
difunctional phosphonic acid with an .omega.-carboxylic acid
functional group to the phosphonic acid)
11-hydroxy-undecylphosphonic acid (a linear, 11 carbon atom
difunctional phosphonic acid having an .omega.-hydroxyl functional
group to the phosphornic acid) were synthesized by a published
procedure. Tetrakis(tert-butoxy)-zirconium (TBZ) was distilled at
10.sup.-1 torr and 80.degree. C. The distilled product was stored
in a nitrogen dry box, in the dark, and at -40.degree. C. until
needed. Otherwise, solvents were used as purchased. Titanium (0.25
mm; 99.6%), aluminum (0.25 mm; 99.0%); and iron (0.125 mm; 99.5%)
foils and titanium Ti-6Al-4V billet (all obtained from Goodfellow,
Inc.) were prepared for use by sanding, followed by cleaning with
methanol, and cut into .about.1 cm*1 cm coupons (foils) or 1 inch
diameter disks (billet). The coupons were dried for at least an
hour before use, and stored in an oven at 200.degree. C.
[0208] The first set of comparative examples demonstrate the films
which can be formed on various native metal oxide surfaces using
ambient temperature contact of the surface with a carboxylic and a
phosphonic acid, both of which represent classes of art-recognized
oxide surface derivatizing agents.
Comparative Example 1
Carboxylic Acid Treatment of Aluminum Native Oxide
[0209] A coupon of aluminum was prepared as described above. A 1.0
mM solution of stearic acid in iso-octane was prepared for
deposition on the aluminum coupon. Deposition was carried out by
immersing the aluminum coupon into the stearic acid solution for 24
hours, then washed with fresh iso-octane. The presence of a stearic
acid film was confirmed by IR spectroscopy. The self-assembled
monolayer alignments were confirmed by contact angle measurements.
Washing the substrates after they were immersed in the carboxylic
acid solutions aided in the removal of molecules that were not
bound to the aluminum, but were merely sitting on the surface.
[0210] The films formed in solution were stable. The stearic acid
film, which formed in 24 hours, was removed by anhydrous ethyl
ether under mild conditions in the same amount of time. The
monolayer-coated aluminum substrate was placed in ether at room
temperature without using any stirring device. Removal of a
significant portion of the film within 90 minutes was confirmed by
IR spectroscopy. After removing the monolayer, it was possible to
establish another monolayer on the aluminum surface by repeating
the same technique. This could be done repeatedly, but there was a
gradual erosion of the aluminum substrate.
[0211] From the IR information, it was apparent that the
interaction between the carboxylic acid and the metal oxide
substrate surface was weak, as illustrated by the ability to
produce and remove the monolayer under mild conditions. The nature
of the interaction is apparently hydrogen bonding between the acid
and the hydroxyls on the surface of the metal. Apparently, covalent
bonds are not formed because, if they were, much more vigorous
conditions would be required to remove the carboxylic acid from the
surface of the metal oxide.
Comparative Examples 2-4
Ambient Phosphonic Acid Treatment of Aluminum, Iron, and Titanium
Native Oxide Surfaces
[0212] Samples of coupons of aluminum, iron, and titanium, prepared
as described above, were treated with an aerosol of
n-octadecanephosphonic acid in tetrahydrofuron (THF) at room
temperature in the ambient environment. Following the spray
application of the acid solution the solvent was allowed to
evaporate at ambient temperature and the derivatized surfaces of
the coupons were analyzed by FTIR. The surfaces where then washed
with THF and analyzed both before and after a peel test using red
Scotch.TM. "650" tape. The analysis shows that on iron, the
phosphonic acid forms a layer on the native surface oxide that,
while of sparse coverage, survives both washing and peel testing.
In the case of the aluminum samples, a weakly bound phosphonic acid
layer is formed that survives washing, but not peel testing. For
the titanium sample, any phosphonic acid which absorbed to the
surface was readily removed by washing with the deposition
solvent.
Comparative Examples 5
Vacuum-Anneling of Phosphonic Acid Coating Applied to Titanium
Native Oxide Surfaces
[0213] A titanium coupon, prepared as described above was treated
with a 0.8 mM THF solution of octadecanephosphonic acid in the form
of an aerosol spray under dry N.sub.2. The treated coupon was
placed under vacuum (10.sup.-1 torr), and sealed off. The coupon
remained in the evacuated vessel for six hours. DRIFT analysis
before and after rinsing of the sample demonstrated that none of
the phosphonic acid remained on the surface after rinsing in
THF.
[0214] The next group of examples demonstrates derivatization of
titanium oxide surfaces according to the present invention using a
phosphonic acid and phosphonic acid derivatives.
Example 4
Formation of Bound Phosphonic Acid Film on a Titanium Native Oxide
Surface
[0215] A titanium coupon, prepared as described above was treated
with a 0.6 mM THF solution of octadecanephosphonic acid in the form
of an aerosol spray under dry N.sub.2. The treated coupon was left
under a current of dry nitrogen until the solvent evaporated.
Following solvent evaporation the sample was heated for 18 hours at
110.degree. C. in air. The coupon was cooled to ambient temperature
and rinsed twice with THF. This cycle of application, heat
annealing, and rinsing was repeated five times. DRIFT analysis of
the resulting coating on the coupon demonstrated that a phosphonate
surface coating was bonded to the surface and remained after
rinsing and peel testing. The coupons thus prepared were stored in
an oven at 200.degree. C. there being no upper limit on annealing
time.
Example 5
Formation of a Difunctional, Bound Phosphonic Acid Film on a
Titanium Native Oxide Surface
[0216] A 5 mM solution of 11-phosphonoundecanoic acid in dry,
distilled THF was aerosol sprayed onto a titanium coupon prepared
as described above using the procedure described above for
preparation of films using difunctional phosphonic acids. Analysis
by infrared spectroscopy (IR) of the resulting surface films
produced show the characteristic IR stretches observed for alkyl
chains and for bound phosphonic acids, indicating that the
phosphonate group was bound to the surface of the coupon and the
.omega.-carboxylic acid groups were oriented away from the surface
and hydrogen bonded.
Example 6
Formation of a Difunctional, Bound Hydroxyphosphonic Acid Film on a
Titanium Native Oxide Surface
[0217] A 10 mM THF solution of 11-hydroxyundecylphosphonic acid was
applied to a titanium coupon, prepared as described above, as an
aerosol using the procedure described for Example 5, except that
baking of the sample was limited to 18 hours post application.
Infrared analysis indicated that the phosphonic acid portion of the
coating precursor was bound to the native oxide and showed a broad
peak between 3300 and 3600 cm.sup.-1 indicative of hydrogen-bonded
hydroxyl groups as well as characteristic peaks for the aliphatic
chain.
Example 7
Formation of Bound, Mixed-Difunctional Phosphonic Acid Coating on a
Titanium Native Oxide Surface
[0218] Using the procedure described for Example 5, above, coatings
comprising mixtures of 11-phosphonoundecanate acid and either
4-phosphonobutyrate, decanephosphonate or a mixture of these
species in any ratio will be prepared by aerosol applications of a
solution containing a mixture of these species. The ratio of
surface bound materials will be found to be close to that of the
ratio of acid constituents of the solution applied. Subsequent
coupling chemistry (with, for example, a phenol or an amino acid)
can be accomplished to optimize yields of elaborated surface films
by controlling the microenvironments of the .omega.-carboxlic acid
termini in this manner. Similar experiments can be done for
mixtures containing .omega.-hydroxyalkylphosphonate as well.
[0219] In the second and third groups of examples, following, films
formed on titanium metal coupons using difunctional phosphonic
acids (both the .omega.-carboxylic acid and .omega.-hydroxyl
functional films) are further reacted with moieties useful in
demonstrating the reactivity of the layer and with other moieties
which are useful in the promotion of bone adhesion.
Examples 8-9
Further Derivatization of Titanium Oxide Surface Bound Difunctional
Phosphonic Acid
[0220] In this second group of examples, the free carboxylic acid
portion of the difunctional phosphonate layer applied to the
surface of a titanium coupon prepared according to Example 5 is
further reacted at the carboxylic acid site by esterification of
the acid with a phenol, an amino-acid, and with a peptide.
Example 10
Formation of Amino Acid Amides of Bound Difunctional Phosphonic
Acid Coating on a Titanium Native Oxide Surface
[0221] Coupons were derivatized with a
carbodiimide/hydroxysuccinimide coupling reagent. Coupons prepared
according to Example 5 were stirred in an aqueous solution (75 mM)
of 1-ethyl-3-(3-dimethyl-aminopropyl)-carbodiimide and 20 mM
N-hydroxysuccinimide to form the imido-adduct of the acid. The
coupons thus treated were then transferred to a beaker of a 75 mM
solution of lysine in water. The coupons were then extensively
rinsed with water and dried under vacuum. FTIR analysis indicates
the presence of an amide (coupling of the carboxylic acid of the
phosphonate and the amine functional group of the lysine amino
acid).
Example 11
Formation of Peptide Thio-Esters of Bound Difunctional Phosphonic
Acid Coating on a Titanium Native Oxide Surface
[0222] The use of a surface of the present invention to bind short
peptides to a Ti or alloy surface is demonstrated next. A
cysteine-modified peptide, RGDC (Arg-Gly-Asp-Cys), described above
which occurs in fibronectin cell-adhesive protein, is selected for
attachment to the carboxylic acid ends of surface layers on
titanium coupons prepared according to Example 5, above. The
coupons are first treated with a solution of
dicyclohexylcarbodiimide and N-(6-hydroxyhexyl)-maleimide in
dichloromethane to provide the .omega.-carboxylic acid groups of
the derivatized surface of the coupon with a maleimide ester group
that will react with thiol functionality in the cysteine of the
modified peptide. Foils are then bathed in an aqueous solution of
RGDC (Arg-Gly-Asp-Cys) to couple the thiol group of cysteine to the
immobilized maleimide group, leading to the attachment of RGDC to
the .omega.-carboxylic acid-maleimide, yielding a bioactivated Ti
surface.
[0223] In this second group of examples, the free hydroxide portion
of the difunctional phosphonate layer applied to the surface of a
titanium coupon prepared according to Example 6 using
11-hydroxy-undecylphosphonic acid is further reacted at the hydroxy
functional group by conventional organic chemistry with dansyl
chloride, an amino acid, and with a peptide.
Example 12
Reaction of Titanium Oxide Surface Bound .omega.-Difunctional
11-Hydroxy-Undecylphosphonic Acid with Dansyl Chloride
[0224] Titanium coupons prepared according to Example 6 above were
placed in a solution of approximately 10 mg of dansyl chloride and
0.1 mL of triethylamine in 10 mL of acetonitrile. The solution was
stirred for 18 hours under N.sub.2. Coupons were removed from the
solution, blotted dry and rinsed with acetonitrile. The coupons
were then subjected to FTIR analysis which indicates, by the
presence of new peaks at .about.1600 cm.sup.-1 and at
.about.1200-1100 cm.sup.-1, that a sulfonate ester formed. The
dansyl adduct has a characteristic fluorescence spectrum, and
fluorescence microscopic analysis of the coupons confirms the
formation of the surface-bound dansyl ester product. The
fluorescence spectroscopy also indicates that the coating is
dense-coverage and uniform over the entire surface of the
coupon.
[0225] For the next two examples, the surface bound
hydroxyphosphonate is converted into the maleimide adduct according
to the following procedure. A coupon prepared according to Example
3, above, is placed into a solution of about 15 mg of
3-maleimido-(propionic-acid-N-hydroxysuccinimide) ester in 10 mL of
acetonitrile. The coupon is then transferred into a nitrogen glove
box and placed into an ambient temperature maleimide solution for
24-72 hours, after which, coupons are removed from the solution and
blotted dry, and rinsed with acetonitrile. FTIR analysis indicates
peaks corresponding to 11-hydroxyundecylphosphonate bound to the
surface of the coupon through the phosphonate functional group,
with additional peaks at .about.1731 and .about.1707 cm.sup.-1
corresponding to the carbonyl stretches of the maleimide
adduct.
Example 13
Reaction of Titanium Oxide Surface Bound .omega.-Difunctional
11-Hydroxy-Undecylphosphonic Acid with Cysteine
[0226] Coupons having the phosphonate-maleimide adduct, prepared as
described above on titanium coupons prepared according to Example
6, were placed in a stirred solution of 15 mg of cysteine dissolved
in 10 mL of doubly distilled, Millipore.TM.--filtered water for
8-24 hrs. The foils were removed from solution, dried, and rinsed
in doubly distilled water. FTIR analysis of the coupons showed
changes in the maleimide carbonyl region and a new peak at
.about.1700 cm.sup.-1, indicative of the presence of cysteine bound
to the coupon.
Example 14
Reaction of Titanium Oxide Surface Bound .omega.-Difunctional
11-Hydroxy-Undecylphosphonic Acid with a Peptide
[0227] Coupons containing the phosphoric coated-maleimide adduct,
prepared as described above from titanium coupons prepared
according to Example 6, are placed in a solution of the peptide
RGDC (Arg-Gly-Asp-Cys) used to prepare coupons of Example 12,
above. The RGDC solution comprises about 10 mg of the peptide in 10
mL of doubly distilled, Millipore.TM.-filtered water. Coupons are
stirred at ambient temperature for about 8 to about 48 hours. The
coupons are removed from solution, dried, and rinsed in doubly
distilled water. FTIR, analysis before and after peptide treatment
demonstrates changes in the maleimide carbonyl region and
broadening in the carboxylate region (.about.1700 cm.sup.-1) which
persists after two solvent rinses, indicating the presence of the
RGDC tetrapeptide bound to the coupons.
[0228] It will be appreciated that peptides and amino acids can be
"tagged" with a fluorescent marker by covalent bonding a small
fluorescent species, such as dansyl chloride as an ester or
thioester to the parent compound. It will be appreciated that amino
acids and peptides which are bound to phosphonate species bonded to
oxide surfaces, such as are described above can be tagged before or
after such bonding reactions. When the surface species amino acid
and peptide adducts are "tagged" in this manner, examination of the
coupons by fluorescence microscopy after derivitization indicates
the coatings of the peptide bounded to the coupon are dense and
uniform over the entire coupon.
[0229] The next group of examples demonstrates the dense-coverage
of a titanium native oxide surface that can be achieved with the
coating of the present invention.
Examples 15-16
Formations of a Phosphonate Coating on a Titanium Quartz
Microbalance Electrode
[0230] As described above, quartz microbance electrodes were
treated with octylphosphonic acid and 11-hydroxyundecylphosphonic
acid to form octylphosphonate and 11-hydroxyundecylphosphonate
coatings on the native oxide layer on the electrodes. The
11-hydroxyundecylphosphonate was further derivatized with maleimide
and RGDC as described in example 11 above. The results of
microbalance measurement of the density of surface coverage for the
two species is presented below in Table 3. TABLE-US-00003 TABLE 3
Surface coverage of Ti by phosphonates. Phosphonate .DELTA.f (Hz)
Coverage (nmol/cm.sup.2)* Octylphosphonate 109 1.49 (1.15) 115 1.58
(1.21) Average (1.18) 11-Hydroxyundecylphosphonate 141 1.42 (1.09)
115 1.15 (0.89) 140 1.42 (1.08) 135 1.36 (1.05) 106 1.07 (0.82) 135
1.36 (1.05) Average (1.00) 11-Hydroxyundecylphosphonate- 37 0.54
(0.42) maleimide 31 0.45 (0.35) 27 0.40 (0.31) Average (0.36)
11-Hydroxyundecylphosphonate- 60 0.38 (0.26) maleimide-RGDC 47 0.23
(0.18) Average (0.22) *As measured by QCM; corrected value for
surface roughness factor measured to be 1.3 by AFM analysis of the
sputtered Ti electrode given in parentheses.
Example 17
Atomic Force Microscopy of an Octadecylphosphonate Coating
[0231] A coating of octadecylphosphonate on the native oxide
surface of a polished titanium coupon was prepared by the aerosol
method described above using a 0.75 mM THF solution of
octadecylphosphonic acid. The acid solution was applied under
nitrogen and evaporated using the ambient method. The
spray-heat-rinse cycle was repeated 6 times. The resultant coating
was studied by atomic force microscopy (AFM) using a Dimension 3000
(Digital Instruments) operated in "soft" TappingMode. An AFM
micrograph of the polished Ti foil surface shows it to have grooves
(resulting from the polishing process), but regions between these
grooves are appreciably flat (mean roughness approximately equal to
0.7 nm). Section analyses examined surface roughness in more
detail. The morphology of the surface changed dramatically on
formation of the octadecylphosphonic acid film. On coated coupons,
AFM micrograph and section analysis showed islands (typical
diameter.apprxeq.50 nm) of similar height (.apprxeq.2.2 nm),
consistent with monolayer formation on the surface, and the mean
roughness of the surface increased to 1.5 nm on monolayer
attachment. With reference to film height data obtained for a
self-assembled monolayer of this same phosphonic acid on mica
(.apprxeq.1.8 nm), an alkyl chain tilt angle of about 33.degree.
was estimated. The AFM analysis indicates the coating is of
dense-coverage. Correction of the microbalance results of Examples
15 and 16 by the AFM data indicate a surface coverage in excess of
20 times of that observed for reactions of the native oxide
hydroxyl sites, described above.
[0232] The next example demonstrates the use of a functionalized
alkylphosphonate coating of the present invention to bond a
bone-growth promoting peptide RGDC (described above) to the surface
of a titanium alloy (Ti-6Al-4V), and the use of this derivatized
surface in adhering and proliferating osteoblasts.
Example 18
Application of a Phosphonate Coating to a Titanium Alloy and
Subsequent Peptide Derivatization to Provide an Osteoblast Adhesion
Promoting Surface
[0233] Disks of Titanium Alloy Ti-6Al-4V prepared as described
above were coated with a layer of 1-hydroxyundecylphosphonate by
placing them in a vessel filled with a 10 mM THF solution of
11-hydroxyundecylphosphonic acid. The THF was allowed to evaporate
and the disks were then baked in an oven at 120.degree. C. for 48
hours and were rinsed in dry THF. Thus prepare the titanium alloy
disks were further derivatized with the cysteine modified
fibronectin cell attachment peptide Arginine Glycine Aspartic acid
(RGDC) which has been described above.
[0234] The RGDC peptide [American Peptide] was bonded to the
phosphonate coating using a maleimide coupling procedure. The
maleimide derivative of the hydroxy functionalized phosphonate
coating was prepared by placing the coated disk into a 5 mM
acetonitrile solution of 3-maleimidopropionic
acid-N-hydroxysuccinimide ester for a period of 24 hours at room
temperature. Thus prepared the maleimide adduct was rinsed with a
fresh acetonitrile solution. The disks were transferred into an
acetonitrile solution of the peptide described above, RGDC, with
stirring for 24 hours, yielding the peptide bound via a thiol-ether
linkage through the cysteine residue to the hydroxy end of the
phosphonate coating.
[0235] These modified titanium alloy disks were examined for their
interaction with human osteoblasts. Human fetal osteoblasts (HFOB
1.19; ATCC) were maintained in a 1:1 mixture of Ham's F12 and
Dulbecco's modified Eagle's medium (DMEM), without phenol red
(GIBCO, BRL), 10% fetal bovine serum (Hyclone Laboratories) and 0.3
mg/ml G418 (GIBCO, BRL). Cells were labeled with 10 .mu.M Cell
Tracker Orange (Molecular Probes, Oreg.) for 30 minutes at
34.degree. C. After this time, the medium was removed and replaced
with fresh medium and serum for an additional 30 minutes at
34.degree. C. Cells were released from tissue culture dishes using
0.2 mg/ml EDTA in PBS, washed with PBS, re-suspended in serum-free
medium at 1*10.sup.5/ml, and 500 .mu.L of the cell suspension was
added to wells containing the metal disk substrates which had been
blocked with 1% BSA in PBS for 30 minutes before cell addition.
Cells were allowed to spread on the substrates for 90 minutes,
after which time they are washed with PBS and visualized using a
Nikon Optiphot-2 microscope. Images were captured using a
Photometrics Coolsnap camera and analyzed using Coolsnap and IP
labs software.
[0236] The results of this study indicate that human osteoblasts
can adhere and propagate on surfaces prepared according to the
present invention.
[0237] Examples 4-17 were duplicated by treating coupons made from
titanium alloy Ti-6Al-4V (Goodfellow) under the same conditions and
with the same reagents used for the titanium coupons used in
Examples 4-17. Results were the same, demonstrating that the
coatings of the present invention can be applied equally well to
the native oxide of titanium alloys using the methods of the
present invention.
[0238] The next group of examples demonstrates the use of
phosphoric acid to form an intermediate layer on titanium metal
native oxide surfaces which may be further derivatized with other
moieties, and a derivatized surface which can promote osteoblast
adhesion and spreading.
Examples 19-24
Dip-Treatment of Titanium Native Oxide Surfaces in Phosphoric Acid
Solution
[0239] In Example 19, a coupon of Titanium foil (99.6+% annealed),
prepared as described above, was immersed in 1.4M aqueous
H.sub.3PO.sub.4 (pH=1.5) at room temperature for one hour, then
heated at 110.degree. C. for greater than 16 hours. After two
rinsings with THF, examination by DRIFT showed that it had a
coating of Ti(H.sub.2PO.sub.4).sub.3 (Ti-phosphate) remained that
could not be rinsed away.
[0240] In Example 20, titanium coupons prepared and described above
were dipped in an aqueous solution of phosphoric acid (1.45 m; pH
1.5) for 1 hr at ambient temperature and pressure. The coupons were
then removed from solution and warmed in an oven at 120.degree. C.
for 18 hours, then cooled, rinsed with water, and "peeled" with
masking tape to remove any weakly adsorbed material. X-ray powder
diffraction analysis and Diffuse Reflectance Fourier Transform
Infrared analysis (DRIFT) confirmed the presence of phosphate
coating (Ti-phosphate).
[0241] Coated coupons were prepared in accordance with Example 20
and further derivatized using the spray/heat/rinse procedure
described above using the reagents indicated below in Table 4.
TABLE-US-00004 TABLE 4 Solute Baking Example Derivatizing Species
conc./solvent temp./time 16 octadecyl(triethoxy)silane 1.8 mM/THF
120.degree. C./24 hours 17 octadecanethiol 1.0 mM/THF 60.degree.
C./24 hours 18 octadecylamine 1.0 mM/THF 60.degree. C./18 hours 19
octadecyl(triethoxy)silane 0.8 mM/THF 120.degree. C./16 hours
[0242] In each case, adherent, dense-coverage coatings of the
reactant found on the surface of the phosphate coated coupon by IR
analysis.
Example 25
Treatment of Phosphate Coatings With Hydrolytically Reactive Metal
Alkoxides
[0243] Coupons prepared according to Example 20 were put in a
horizontal tube which could be externally cooled and which was
equipped with two stopcocks for exposure to vacuum (10.sup.-3 Torr)
or to vapor phase tetra-(tert-butoxy) zirconium
(Zr(--O-t-butyl).sub.4). Coupons were subjected to three cycles
each consisting of alternating exposure to vapor of
Zr(--O-t-butyl).sub.4 with external evacuation for 15 minutes,
followed by 30 minutes exposure to the organometallic reagent vapor
without external evacuation. The first cycle was done at room
temperature, and the latter two with external cooling by dry ice.
Coupons were then subjected to room temperature vacuum (10.sup.3
Torr) for 16 hours to remove any physisorbed Zr(--O-t-butyl).sub.4.
DRIFT analysis confirmed formation of dense-coverage surface
zirconium alkoxide.
Example 26
Derivatization of a Dense-Coverage Zirconium Alkoxide Bound to
Titanium
[0244] Coupons prepared according to Example 25 were sprayed with
1.75 mM solution of octadecylphosphonic acid in dry tetrahydrofuran
(THF). Samples were evacuated overnight (0.1 Torr), rinsed with
THF, "peeled," tested and analyzed by DRIFT. The analysis
demonstrated an adherent alkylphosphonate coating bonded to the
zirconated surface.
[0245] The derivatization reactions of Examples 19-26 were
repeated, using the same reagents and conditions on coupons of
Ti-6Al-4V (Goodfellow) prepared according to the procedure
described for Example 20 above. Analysis of the coatings prepared
showed that titanium alloy can be derivatized in the same manner
with the same results seen from the titanium.
[0246] The next group of examples demonstrates the use of a
phosphate coating of the present development to provide a
derivatized surface on a titanium material which promotes the
adhesion and proliferation of osteoblasts.
Examples 27-28
Adhesion of Osteoblasts to a Titanium Material Phosphate Coated
Peptide Derivatized Surface
[0247] Disks cut from titanium billet and from titanium alloy
Ti-6Al-4V billet were prepared and coated with a phosphate coating
according to Example 20.
[0248] A phosphate coated disk of each material was placed in a
Teflon.TM. well, and they were each treated with a solution of
amino propyl(triethoxy) silane (10 mM in THF), and then solvent
rinsed, with sonication, to give surface-bound 3-amino-propyl
siloxanes. These disks were then further derivatized by placing
each in a 5 mM acetonitrile solution of 3maleimidopropionic acid
N-hydroxysuccinimide ester for 18 hours at room temperature to give
the maleimide adduct. The disks were removed from solution, solvent
evaporated, and analyzed by IR. They were then rinsed in
acetonitrile, with sonication, and dried in vacuo (0.1 Torr). The
disks were further derivatized by placing them into a solution of
the RGDC peptide used in Example 18 above, (5 mM), prepared in 5 ml
of purified water (Millipore), with the pH adjusted to 6.5 using
0.1M NaOH. The disks remained in the peptide solution stirring at
room temperature for 24 hours. Formation of the surface bound RGDC
was verified by IR. The disks were then rinsed with water, dried,
subjected to tape peel testing, and reanalyzed by IR. The peptide
coating was found to be adherent.
[0249] The peptide coated disks were subjected to the human
osteoblast test described above in Example 18. The results showed
that the surface promoted the adhesion and proliferation of
osteoblasts.
Example 29
Derivitazation of Phosphate Coating with 11-Mercaptoundecanoic
Acid
[0250] Mercaptoundecanoic acid was recrystallized from ethanol at
room temperature. A solution of mercaptoundecanoic acid (1.0 mM in
THF) was applied by aerosol deposit onto coupons of titanium and of
titanium alloy Ti-6Al-4V. The coupons were placed under N.sub.2 for
6-12 hours in a horizontal tube equipped with a stopcock to
regulate N.sub.2 flow and pressure, then evacuated at 0.1 Torr for
at least 4 hours, and analyzed by DRIFT. A dense coating of the
mercaptan was found adhered to the surface of both the metal and
alloy.
[0251] Next is presented an example of using a bisphosphonic acid
to provide an adherent coating layer which is further derivatized
to form a coating having a phosphonate segment and a linking
segment. Additional examples are presented in which this segmented
coating layer is further derivatized to provide a peptide-bearing
surface, a calcium apatite surface and a mixture of peptide and
calcium apatite.
Example 30
Derivatization of the Native Oxide Surface of Ti-6-Al-4-V Titanium
Alloy by Formation of a Surface Coating Layer Having a
1,6-Diphosphonohexane Segment and a Linking Segment
[0252] A coupon of Ti-6-Al-4-V titanium alloy (extra low
interstitial grade 3/8'' diameter rod, from Titanium Industries,
Morristown, N.J.) was prepared by cutting 1 mm sections from the
rod stock using an art recognized wire electric discharge cutting
technique. The surface of the coupon was prepared by sanding and
then successively washed with methylene chloride, 2-butanone, and
then methanol. After a methanol rinse, the coupons were stored
under air in an oven at 200.degree. C.
[0253] The bisphosphonic acid was synthesized and purified
according to published procedures; all other reagents were used as
received. A coating layer was applied to the coupon by dropwise
application of a 1.0 mM aqueous solution of the
1,6-hexane-bis(phosphonic acid) onto the surface of the coupon
under ambient conditions and transferring the sample into a
120.degree. C. oven in air for 48 hours. At the end of the baking
period, the samples were rinsed with distilled water, sonicated in
distilled water for 20 minutes (Branson 2610 Sonic Cleaner), and
dried in vacuo at ambient temperature (about 0.01 mm Hg for 5
hours). The presence of a bisphonate layer was verified by infrared
(IR) analysis as described above.
Preparation of a Coating Layer Having a Bisphosphonate Segment and
an Alkoxide Linking Segment
[0254] The surface of the bisphosphonate coating layer on coupons,
prepared as described above, was further derivatized by reaction
with a zirconium alkoxide. Thus, a coupon coated as described above
was placed into a vacuum deposition chamber which was fitted with a
bulb containing freshly vacuum distilled zirconium
tetrakis(tert-butoxide). The chamber was closed and evacuated to
5.5 millitorr. The chamber was sealed from the vacuum source and
the bulb was opened, admitting zirconium alkoxide vapor to a
pressure of about 3 millitorr for 30 minutes at ambient
temperature. The chamber was again evacuated to 5.5 millitorr and
the cycle repeated twice more. At the end of the third exposure to
zirconium alkoxide, the sample was subjected to a vacuum of 3
millitorr for two hours. The presence of the zirconium linking
segment bound to the surface coating layer was verified by IR
analysis, as described above. Coupons having a segmented coating
layer prepared according to this procedure were further handled in
a nitrogen glove box.
Preparation of a Coating Layer Having Bound Peptide
[0255] The coupons having a coating layer comprising a
bisphosphonate segment and an alkoxide segment (segmented coating
layer), prepared as described above, were subjected to further
derivitization reactions to bind a peptide to the zirconium
alkoxide linking segment. This was accomplished by reacting the
residual alkoxide moieties with a difunctional organic acid
(6-maleimido-hexanoic acid, Sigma, used as received), bonding the
carboxylate functional group to the zirconium. The surface bound
acid was then reacted at the maleimide functional group with a
peptide derivative. Thus, an anhydrous 1.0 mM tetrahydrofuran (THF)
solution of the carboxylic acid was aerosol sprayed in a dry box
onto the coupon prepared as described above, according to the
aerosol procedure described above. The samples were subjected to a
vacuum of about 0.01 torr for 12 hours, then rinsed and sonicated
in THF and dried again in vacuo. The binding of the carboxylic acid
species to the zirconium segment of the coating layer was verified
by IR analysis, as described above. A 2 mM aqueous solution of the
cysteine modified RGD peptide (RGDC) described above was adjusted
to pH 6.5 with NaOH. Coupons which had been previously derivatized
with 4-maleimidobutyric acid were stirred in the RGDC peptide
solution at 25.degree. C. for 24 hours.
[0256] The coupons which were derivatized with RGDC peptide were
incubated with human fetal osteoblasts, as described above. These
surfaces were found to promote cell attachment and
proliferation.
Example 31
Preparation of a Coating Layer Having a "Patterned" Alkoxide
Linking Segment Surface
[0257] It will be found that application of a small droplet of a
solution of zirconium tetrakis(tert-butoxide) (prepared as
described above in Example 30) to the surface of a coating layer
prepared from 1,6-hexanediphosphonic acid in accordance with the
process described in Example 30 will provide a zirconium alkoxide
linking segment confined to the area of the surface contacted by
the droplet. By applying small droplets to the surface in selected
areas it will be found that subsequent treatment of the surface
with 6-maleimido-hexanoic acid in accordance with the procedure
described for Example 30 will provide bonding of the carboxylic
acid to the surface only in those areas which were contacted by the
zirconium alkoxide. It will be found that subsequent treatment of
the surface with RGDC peptide according to the procedure described
above in Example 30 will yield a surface which has a "pattern" of
the peptide bound to the surface only in those areas of the surface
having the zirconium alkoxide linking segment.
[0258] It will be appreciated that the surface can be provided with
a "pattern" using the process described in Example 31 by contacting
the surface with a solution of the zirconium alkoxide through a
"mask", or by direct application of a solution to the surface in a
pattern, or by any of the known techniques for application of a
pattern, for example, by "inkjet" printing or by "screen"
printing.
Example 32
Formation of Calcium Hydroxyapatite Surface
[0259] It will be found that when the bisphonate coating layer
prepared as described in Example 30 is subsequently reacted with a
calcium alkoxide instead of a zirconium alkoxide, there is provided
a segmented coating layer having a bisphosphonate segment bonded to
the native surface oxide layer and a calcium alkoxide linking
segment bonded to the bisphosphonate segment (hereafter,
calcium-functionalized coating layer). It will also be found that a
calcium-functionalized coating layer provides a surface upon which
a synthetic calcium apatite surface can be formed by sequentially
reacting the calcium-functionalized coating layer with phosphoric
acid and a calcium alkoxide reagent. Thus, by substituting
calcium-bis(2-methoxy ethoxide) for zirconium
tetrakis(tert-butoxide) in the procedure described above for the
preparation of a coating layer having a zirconium alkoxide linking
segment (Example 30), a segmented coating layer having
bisphosphonate segment bonded to the native oxide layer of a
titanium coupon and a calcium alkoxide segment bonded to the
bisphosphonate segment will be prepared.
[0260] It will be found that by reacting the calcium alkoxide
functionalized coating thus prepared with an aqueous solution of
phosphoric acid, a calcium hydroxy-phosphate surface is prepared.
It will be found that by alternatively reacting the surface thus
prepared with additional amounts of calcium bis(2-methoxy ethoxide)
and phosphoric acid, a calcium hydroxy-phosphate surface layer of
suitable thickness to permit growth of an adherent layer of
hydroxyapatite on the surface using known sol-gel processing
techniques is provided.
Example 33
Preparation of "Mixed" Pattern Surfaces
[0261] It will be found that a coating layer prepared from
treatment of a titanium coupon with a solution of
1,6-hexanediphosphonic acid according to the process described in
Example 30 can be provided with a pattern comprising interspersed
regions of osteoblast adhesion-promoting peptides and
hydroxyapatite by patterning the surface first with a peptide that
promotes osteoblast adhesion using the process described in Example
31 to pattern the surface with zirconium linking segments,
attaching to the zirconium linking segments (6-maleimido) hexanoic
acid according to the process described in Example 30, and then
further derivatizing the surface of the coating layer with a
calcium alkoxide linking segment in the areas not receiving a
zirconium alkoxide linking segment by reacting the surface with a
solution of calcium bis(2-methoxy ethoxide) according to the
procedure described in Example 32. It will be found that such a
surface will promote osteoblast adhesion and bone tissue
infiltration into the surface when the surface is placed into
contact with living bone tissue.
Example 34
A Phosphonate/Epoxide Segmented Coating Layer
[0262] Titanium coupons having a coating prepared according to
Example 3 above (a phosphonate coating derived from
11-hydroxyundecylphosphonic acid) were further derivatized with an
epoxy linking group by applying a film of Cytec Fiberite FM
1000.TM. epoxy adhesive to the surface. Before the adhesive cured,
a second titanium coupon prepared according to Example 3 was placed
in contact with the epoxy such that a lap joint was formed having a
284 mm.sup.2 area. The epoxy was permitted to dry under ambient
conditions. Additional examples were prepared from titanium metal
coupons having a sanded, washed, and baked surface, as described
above, but without a phosphonate coating. The strength of the joint
between the coupons for the coated and uncoated samples was tested
according to ASTM testing standard F1044-99. It was found that on
average, the joint between the uncoated coupons failed at 40 MPa
and between the coated coupons, the joint failed on average at
about 60 MPa of applied pressure.
Example 35
Shear Testing of Phosphonate Coatings
[0263] To test the Mode I (shear) stress of the various interfaces,
a modified version of ASTM test 1044-99 was used. Coupons of
titanium metal and titanium alloy (Ti-6Al-4V)
(2''.times.1/2''.times.1/8'') were cut via electric discharge
machining and were polished. Surfaces were solvent cleaned and
stored at 200.degree. C. until use. Surface SAMs (self-assembled
monolayers) were grown by the T-BAG method described in U.S. patent
application Ser. No. 10/701,591; coupons were suspended vertically
in a 0.1 mM solution of the appropriate phosphonic acid and the
solvent was allowed to traverse the surface, leaving a SAM of the
phosphonic acid. The SAM was then covalently bonded to the surface
as the phosphonate by heating to 140.degree. C. for 48 hours. The
coupons were then rinsed extensively with solvent and were analyzed
by IR after each rinse. The IR spectra after rinsing demonstrated
ordered phosphonate films in which substantially all the
phosphonate were covalently bound by at least on one oxygen to the
oxide surface of the coupon. Treated coupons were then joined
together using Cytec Fiberite Epoxy FM-1000, with a spatial overlap
as stipulated by ASTM 1044-99. Curing was performed in a holder,
and coupon "sandwiches" were then heated in a programmable furnace,
slowly ramping the temperature from room temperature to 170.degree.
C. The oven temperature was then held at 170.degree. C. for 90
minutes and was ramped back down to room temperature. Once cured,
the sandwiches were placed in a holder to ensure that any force
applied is shear (Mode I). The sandwich and holder were placed in
an Instron 1331 load cell and a controlled amount of force was
applied until failure of the interface occurred, the failure stress
was noted. See FIG. 11. Shear stress measurements were conducted on
uncoated coupons and on coupons coated with octadecylphosphonate
(Ti-Phosphonate 18), 11-hydroxy-undecylphosphonate
(Ti-Phosphonate-OH), 12-phosphonododecylphosphonate
(Ti-Phosphonate-12P), 4-phosphonobutylphosphonate
(Ti-Phosphonate-4P), 4-phosphono-2-butene-1-phosphonate
(Ti-Phosphonate-4'P), cross linked
4-phosphono-2-butene-1-phosphonate (Ti-Phosphonate-4'P cross
linked), 4-phosphono-p-xylenyl-phosphonate (Ti-Phosphonate-4XP),
and 4-p-anthracenyl-phosphonate (Ti-Phosphonate-4A). Surface
loadings which for the present invention is equivalent to surface
phosphorous-containing group densities, were also measured via QCM
as described above. The test results are shown in Table 5
below.
[0264] Because strengths of the interfaces on Ti were measured
mechanically, only the lower limit for the shear strength of
Ti-Phosphonate-OH>52 MPa could be determined because the epoxy,
not the interface, fractured.
[0265] Differences in interfacial shear strengths of the other
comparably loaded interfaces may be attributed to the respective
tail group reactivities with the epoxy. In the case of
Ti-11-hydroxyundecylphosphonate, the high molecular surface density
in the interface also provides a closely packed film of
nucleophilic --OH at the film terminus. TABLE-US-00005 TABLE 5
Maximum shear strength and loading of functionalized/ derivatized
titanium surfaces. Macroscopic Interfacial Shear Surface Loading
Sandwich Substrate Strength (MPa) (nmol/cm.sup.2) Uncoated
Ti-6Al-4V 40.1 .+-. 2.9 N/A Ti-Phosphonate-18 11.9 .+-. 3.5 1.18
.+-. 0.03 Ti-Phosphonate-OH >52.1 .+-. 2.1 1.00 .+-. 0.03
Ti-Phosphonate-12P 51.4 .+-. 3.1 0.52 .+-. 0.02 ##STR1##
Ti-Phosphonate-4P 40.0 .+-. 4.0 0.40 .+-. 0.03 ##STR2##
Ti-Phosphonate-4'P 71.2 .+-. 7.4 0.77 .+-. 0.01 ##STR3##
Ti-Phosphonate-4'P crosslinked 50.3 .+-. 2.4 0.77 .+-. 0.01
##STR4## Ti-Phosphonate-4XP 41.1 .+-. 2.6 0.25 .+-. 0.01 ##STR5##
Ti-Phosphonate-4A N/A 0.1 .+-. 0.03
[0266] All interfacial shear strengths exceeded the FDA minimum (20
MPa) required for sprayed coatings on surgical implants except for
titanium surfaces coated with octadecylphosphonate. See, e.g., U.S.
Provisional Application No. 60/684,159.
[0267] The sandwiches made from titanium surfaces coated in
octadecylphosphonate (Ti-Phosphonate-18) had the weakest composite
shear strength, consistent with the surface being covered
essentially by a grease: although the phosphonate-titanium
interface may be strong, the methyl-terminus of the SAM affords no
points of attachment for the epoxy, and thus the epoxy can simply
slide off of the SAM-coated titanium.
[0268] The .omega.-modified SAMs show marked increases in their
composite shear strength from that of the methyl-terminated SAM.
The sandwiches made from hydroxyl-terminated SAM and the
phosphonate-terminated SAM have reactive tail groups that are able
to chemically bond to the epoxy. As such, the epoxy can be firmly
attached to the SAM-coated titanium. Most importantly, SAM coated
titanium composites have shear strength greater than that of native
Ti-6Al-4V. The fact that composite shear strength is increased
(above the benchmark of the FDA) over untreated titanium is
attributed to a greater number of reactive sites on the
.omega.-functionalized SAM films than on native Ti-6Al-4V (the
native oxide surface of titanium has only about 16% hydroxyls of
its surface oxygen content or lower when treated with high
temperatures prior to exposure to oxygen).
[0269] In order to test the dependence of shear strength on alkyl
chain length for a phosphonate-titanium interface, a short chain
diphosphonate film of (4-phosphonobutylphosphonate) was prepared on
the surface of titanium. This surface was analyzed via IR to gauge
any ordering of the alkyl chains, however v.sub.CH2 could not be
detected, most likely due to the short chain length. However, a
broad band for the phosphonate was observed
(v.sub.PO.apprxeq.1200-1050 cm.sup.-1). The shear strength of this
interface was measured (40.0.+-.4.0 MPa), which is less than that
of the 12-carbon analog (>50 MPa). This difference in
interfacial shear strength may be attributed to chain length, but
differences in surface loadings between the two phosphonic acids
were also measured (Table 5): it may be that the greater van der
Waals interactions between longer chains may help facilitate
ordered SAM formation which may lead to greater surface densities
for Ti-Phosphonate-12P (1,12-diphosphonododecane) than for its C-4
analog and hence greater interfacial shear strength.
[0270] Loadings of both Ti-Phosphonate-12P and Ti-Phosphonate-4P
were determined gravimetrically via quartz crystal microgravimetry
(QCM) (Table 5 above). From these loading data, it is seen that the
strength of the interface as measured is proportional to the
diphosphonate loading of the surface. If the interfacial shear
strength is normalized on a per molecule basis, interfacial shear
strengths of long and short chain phosphonates per molecule are the
same: the greater loading of Ti-Phosphonate-12P vs.
Ti-Phosphonate-4P leads to a greater number of sites of attachment
between the surface and the SAM, and between the SAM and the epoxy,
thus leading to greater composite shear strength for the longer
chain system.
[0271] The structure of the alkyl chain was also varied. SAMs of
4-phosphono-2-butene-1-phosphonate were prepared on Ti
(Ti-Phosphonate-4'P) to give a SAM containing an olefinic group.
Upon exposure to ultraviolet radiation, the SAM was forced to
crosslink. SAMs of 4-phosphono-p-xylenyl-phosphonate were prepared
on Ti (Ti-Phosphonate-4XP), yielding a surface film containing an
aromatic group. SAMs of Ti-Phosphonate-4'P without crosslinking
demonstrated the same trend as observed for Ti-Phosphonate-12P and
Ti-Phosphonate4P (i.e. greater loading leads to greater shear
strength). Upon crosslinking, the SAM of Ti-Phosphonate-4'P
underwent a reduction in interfacial strength, although not losing
film loading, demonstrating a dependence of film structure on its
shear strength. In further demonstration, SAMs of
Ti-Phosphonate-4XP had less shear strength than either
Ti-Phosphonate-12P, Ti-Phosphonate4P, or Ti-Phosphonate-4'P, but
this shear strength did not scale simply with film loading; there
may be a dependence on film structure in that the aromatic group
apparently adds strength to the system.
[0272] It will be appreciated that phosphorous and phosphonate
based coatings may also be prepared and covalently bound to
implantable surfaces at lower surface loading densities. The shear
strength of these less densly coated surfaces will be less then the
shear strength of the tightly packed coated surfaces listed in
Table 5. For example, the shear strength coatings with lower
surface loading densities will be, for example, about 35 MPa or
about 30 MPa or even at least about 20 MPa.
Example 36
Tensile Testing of Phosphonate Coatings
[0273] Tensile strength is an important factor for evaluating
interfacial adhesion of coatings on devices. Tensile strength tests
of the coatings disclosed herein were conducted using a modified
version of ASTM Test #1147-99 with a testing apparatus similar to
that shown in FIG. 12. The smooth flat surface of a threaded
titanium or Ti-6Al-4V cylindrical fitting 11 was coated with
11-hydroxyundecylphosphonate according to the methods disclosed
herein. This was affixed to a matched piece of untreated titanium
13 using Cytec FM-1000 epoxy layer 15. Tensile load (F) was applied
to each test specimen at a constant rate until separation of the
components was been achieved.
[0274] The failure point of was measured to be 81.1 MPa,
statistically similar for the failure points for uncoated (82.7
MPa) and uncoated grit blasted (84.5 MPa) samples. The tensile
strength for the epoxy was reported to be .about.82 MPa, so it is
likely that for each sample, the failure of the epoxy layer was
what took place during testing. Each interface exceeds this
strength, but attaining a value at failure would not be possible
without a stronger epoxy bonding layer.
[0275] It will be appreciated that the tensile strength of
alternate phosphonate coatings, particularly alkylphosphoate
coatings, for example. Octadecylphosphonate, will be lower than
.about.82 MPa, for example at least about 70 Mpa, or at least about
60 MPa, or at least about 40 MPa-50 MPa. In addition, it will be
appreciated that phosphorous and phosphonate based coatings may
also be prepared and covalently bound to implantable surfaces at
lower surface loading densities. The tensile strength of these less
densly coated surfaces will be less then the shear strength of the
tightly packed coated surfaces. For example, the tensile strength
of coatings with lower surface loading densities will be, for
example, about 50 MPa or about 35 MPa or about 30 MPa or even at
least about 20 MPa.
Example 37
Ostoblast Adhesion on RGD-Coated Phosphonate-Functionalized
Titanium
[0276] While the shear strength of the chemical films on implant
materials is important, often the limiting factor of implant
stability is the bone-implant interface. A common guide to measure
the osteointegration of potential implant surfaces is to monitor
osteoblast adhesion and spreading through in vitro cell studies.
The efficacy and biocompatibility of the films were then tested in
short term in vitro cell studies. Samples of titanium and
Ti-Phosphonate-OH processed with RGD and Ti-Phosphate-OH processed
with RGD were exposed to human fetal osteoblast culture.
In Vitro Cell Adhesion Studies
[0277] Human fetal osteoblasts (HFOB 1.19; ATCC) were maintained in
a 1:1 mixture of Ham's F 12 and Dulbecco's modified Eagle's medium
(DMEM) without phenol red (GIBCO, BRL), 10% fetal bovine serum
(Hyclone Laboratories) and 0.3 mg/ml G418 (GIBCO, BRL). Cells were
labeled with 10 .mu.M Cell Tracker Orange (Molecular Probes, Oreg.)
for 30 min at 34.degree. C. After this time, the medium was removed
and replaced with fresh medium and serum for an additional 30 min
at 34.degree. C. Cells were released from tissue culture dishes
using 0.2 mg/ml EDTA in PBS, washed with PBS, resuspended in
serum-free medium at I.times.10.sup.5/ml, and 500 ml of the cell
suspension was added to wells containing the alloy substrate disks
which had been blocked with 1% BSA in PBS for 30 min before cell
addition. Cells were allowed to remain on the substrates for
specified periods of time. Samples were washed with PBS and
visualized using a Nikon Optiphot-2 microscope. Images were
captured using a Photometrics Coolsnap camera and analyzed using
Coolsnap and IP labs software. A quantitative assessment of cell
coverage was carried out by counting the number of cells from three
random fields per substrate (0.52 mm.sup.2); values are expressed
as the mean number of cells present.
[0278] To test the stability of the interfaces under physiological
conditions and to determine their efficacy for cell adhesion and
spreading, human fetal osteoblasts were incubated with unmodified
or variously surface-modified Ti-6Al-4V ELI for 90 minutes, 24
hours, and 3 days. Cells were previously tagged with a fluorescent
marker so that cell adhesion, spreading, and counting could be
monitored by fluorescence microscopy. Very little osteoblast
adhesion occurred on unmodified Ti-6Al-4V ELI or
.omega.-hydroxy-terminated alkylphosphonate-modified surfaces. A
striking observation was made for the Ti-Phosphate-modified
surface, where cell adhesion was initially quite efficient. Without
being bound by theory, it is believed that the presence of exposed
phosphate groups of Ti-Phosphate in conjunction with chemically
bonded RGD creates an especially attractive mixed-function
environment for the osteoblasts. Unfortunately, the inherent
hydrolytic instability of Ti-Phosphate affects the long-term
viability of this interface; after 3 days, loss of surface material
was visually apparent. An RGD-modified silane/Ti-6Al-4V surface
underwent a similar process in which initial osteoblast adhesion
was marked for 24 hours, but showed signs of failure after 3 days.
This indicates that the surface bound siloxanes may be
hydrolytically labile after prolonged exposure to physiological
conditions. In contrast, adhesion and spreading of the osteoblasts
on RGD-modified phosphonate: Ti-6Al-4V were quite substantial after
24 hours and even more so after 3 days. The morphology and actin
cytoskeleton of cells were observed by staining with rhodamine
phalloidin. Cells remained small and rounded with no organized
actin cytoskeleton on control substrates. However, more than 90% of
cells adherent to RGD-modified substrates became well spread and
organized their actin filaments into robust stress fibers. See,
e.g., U.S. Provisional Application No. 60/684,159.
Example 38
Cell Resistance and Oxidative Stability of Modified Titanium
Surfaces
[0279] As set forth in U.S. Provisional Application No. 60/684,159,
two methods were used to surface-treat disks of Ti-6Al-4V with
methyl-terminated poly(ethylene glycol). The first involved simply
reacting methyl-terminated poly(ethylene glycol) (mPEG)
succinimidoyl propionate (MW 5000 Da) with otherwise untreated
disks. The Ti-mPEG surface was analyzed by IR and showed peaks
corresponding to v.sub.CH.sub.2.sub., asymm.apprxeq.2925 cm.sup.-1,
v.sub.CH.sub.2.sub.,symm.apprxeq.2850 cm.sup.-1,
v.sub.C(O)O.C..apprxeq.1734 cm.sup.-1, v.sub.EG CH.sub.2
.sub.wag.apprxeq.1346 cm.sup.-1, v.sub.EG CH.sub.2
.sub.twist.apprxeq.1225 cm.sup.-1, and V.sub.C--O--C.apprxeq.1085
cm.sup.-1. Reproducibly coating the surface this way was
problematic because of the low surface --OH content of the
Ti-6Al-4V native oxide. In the second, mPEG was covalently bound to
an omega-hydroxy-functionalized phonsphonate titanium surface. The
Ti-11-hydroxyundecylphosphonate-mPEG surface was analyzed by IR and
showed peaks indicative of hydroxy-functional phosphonated
titanium, as well as for PEG (v.sub.C(O)OC.apprxeq.1734 cm.sup.-1,
v.sub.EG CH.sub.2 .sub.wag.apprxeq.1352 cm.sup.-1, v.sub.EG
CH.sub.2 .sub.twist.apprxeq.1215 cm.sup.-1, and
v.sub.C--O--C.apprxeq.1085 cm.sup.-1; the latter peak overlaps with
V.sub.P.dbd.O of the underlying monolayer). The third film was a
self-assembled monolayer of 11-hydroxyundecylphosphonic acid, which
has been described previously. This latter
Ti-11-hydroxyundecylphosphonate surface typically exhibits FTIR
peaks at .about.2920-2910 cm.sup.-1 (--CH.sub.2--, having a peak
width at half-height from about 2 to about 10 wavenumbers, also
from about 3 to about 8 wavenumbers) and at .about.1090 cm.sup.-1
(--P.dbd.O/--P--O, having a peak width at half-height from about 15
to about 45 wavenumbers, or for example from about 20 to about 40
wavenumbers, for example of about 30 wavenumbers).
[0280] Human fetal osteoblasts were cultured with untreated alloy
discs and the three surfaces described above. After 90 minutes,
essentially no cells were attached to any of these surfaces,
demonstrating cell resistance at this early time point. After 24
hours, the differential effectiveness of the surface treatments was
noticeable. Both PEG-treated surfaces (first and second above)
showed greater resistance to osteoblast adhesion compared to the
untreated alloy, but Ti-mPEG was the less effective of the two.
Some areas of the surface of Ti-mPEG resisted cellular adhesion,
but these were intermixed with regions showing an increased number
of attached cells which had spread; this may be due to incomplete
surface coverage of the Ti by reaction with the mPEG succinimidoyl
propionate. Significantly, the simple phosphonate monolayer
Ti-11-hydroxyundecylphosphonate (third film) was as effective in
resisting osteoblast adhesion as was
Ti-11-hydroxyundecylphosphonate-mPEG, with only a small number of
poorly spread cells present.
[0281] The resistance to oxidation of Ti-mPEG, as well as
Ti-11-hydroxyundecylphosphonate and
Ti-11-hydroxyundecylphosphonate-mPEG, were probed using a
"Fenton-like" reagent (FLR) mixture of TiCl.sub.3, EDTA and 30% aq.
H.sub.2O.sub.2, in a ratio of TiCl.sub.3:EDTA:H.sub.2O.sub.2 of
.about.14 mM:.about.14 mM:.about.80 mM. In particular, a solution
of oxidant was prepared in 50 ml Milli-Q water by sequential
addition of 0.1 g TiCl.sub.3, 0.27 g EDTA, and 0.45 ml of 30%
H.sub.2O.sub.2; the pH of this solution was adjusted to .about.7.5
using 0.5 M potassium carbonate. This system is an active source of
hydroxyl radical and is known to be an aggressive oxidant that
mimics macrophage induced oxidation in response to immunological
challenge. Resistance to such oxidation was first noted
qualitatively using FTIR before and after treatment. Noteworthy are
the observations for Ti-11-hydroxyundecylphosphonate and
Ti-11-hydroxyundecylphosphonate-mPEG (FIG. 1) and Ti-mPEG (FIG. 2)
surfaces that peaks at .about.1215 cm.sup.-1 (v.sub.EG CH.sub.2
twist) and at .about.1085 cm.sup.-1 (overlapping v.sub.C--O--C and
v.sub.P.dbd.O), were markedly diminished by this treatment; in
particular, no absorption remained at .about.1085 cm.sup.-1 when
DANSYLated TiP was treated with the FLR, but the peak at
.about.1085 cm.sup.-1 for oxidized
Ti-11-hydroxyundecylphosphonate-mPEG was reduced in intensity to
that of the starting film of Ti-11-hydroxyundecylphosphonate. In
contrast, the spectrum for Ti-11-hydroxyundecylphosphonate (FIGS.
3(a) and 3(b); v.sub.CH2, asymm=2917 cm.sup.-1 ;
v.sub.CH2,symm=2848 cm.sup.-1; v.sub.P.dbd.O=1085 cm.sup.-1) was
essentially unchanged, and no evidence was found for any carboxylic
acid or aldehyde degradation products. Indeed, oxidation of
Ti-11-hydroxyundecylphosphonate-mPEG yielded a material that by IR
was nearly identical to independently prepared
Ti-11-hydroxyundecylphosphonate.
[0282] Comparative oxidative stability of films
Ti-11-hydroxyundecylphosphonate and
Ti-11-hydroxyundecylphosphonate-mPEG was assessed quantitatively
via fluorescence spectroscopy of surfaces that were derivatized by
DANSYLation. In particular, as shown in Table 6 below,
Ti-11-hydroxyundecylphosphonate (1 nmol/cm.sup.2 surface --OH group
density by QCM) is not significantly degraded by exposure to the
FLR. This stability may be due to the highly ordered packing of the
alkyl chains in the monolayer of Ti-11-hydroxyundecylphosphonate
which makes ether group .quadrature.-C--H bond abstraction
sterically difficult; such abstraction processes are believed to
involve oxygen-stabilized intermediate radicals, which may not be
conformationally accessible in the tightly packed film. Simple
Ti-mPEG was significantly degraded by the FLR, as shown by IR.
[0283] Treating Ti-11-hydroxyundecylphosphonate-mPEG with the FLR
also resulted in a noticeable reduction in intesity of PEG-related
peaks (v.sub.EG CH.sub.2 .sub.twist.apprxeq.1215 cm.sup.-1,
v.sub.C--O--C.apprxeq.1085 cm.sup.-1) in the IR; indeed the IR
spectrum of Ti-11-hydroxyundecylphosphonate-mPEG after treatment
with the FLR closely resembles that of the starting
Ti-11-hydroxyundecylphosphonate. Apparently, radical-initiated
cleavage of PEGylated species is not sterically inhibited as it is
in Ti-11-hydroxyundecylphosphonate. Oxidative removal of sterically
large mPEG groups should expose --OH sites of
Ti-11-hydroxyundecylphosphonate to become available for DANSYL
coupling, and indeed after Ti-11-hydroxyundecylphosphonate-mPEG was
treated with the FLR, the yield of surface DANSYLation actually
increased from .about.0.17-0.31 nmol/cm.sup.2, approaching that for
TiP, itself. Thus, it seems that whereas oxidizing conditions
substantially degrade the PEG in
Ti-11-hydroxyundecylphosphonate-mPEG, they leave the underlying
film of Ti-11-hydroxyundecylphosphonate intact. TABLE-US-00006
TABLE 6 Surface coating loadings determined by fluorescence
spectroscopy. DANSYLated derivative Loading by .quadrature.S
Loading (nmol/cm.sup.2) by QCM Pre- Post- Surface Coating
(nmol/cm.sup.2) Oxidation Oxidation Ti-11- 1.00 .+-. 0.09 0.41 .+-.
0.10 0.39 .+-. 0.11 hydroxyundecylphosphonate Ti-11- 0.11 .+-. 0.02
(0.33 .+-. 0.07; hydroxyundecylphosphonate- by QCM) mPEG Ti-mPEG
0.01 .+-. 0.01 0.17 .+-. 0.04 0.31 .+-. 0.08
[0284] As a check on this method, surface loadings for
"pre-oxidation" Ti-11-hydroxyundecylphosphonate and
Ti-11-hydroxyundecylphosphonate-mPEG species as determined by
cleavage/fluorescence spectroscopy were compared with those
measured gravimetrically by QCM. Since the amount of DANSYL
fluorophore on Ti-11-hydroxyundecylphosphonate is similar in both
pre- and post-treatment species (0.41 and 0.39 nmol/cm.sup.2 ,
respectively, as measured by cleavage/fluorescence), we conclude
that TiP is not significantly degraded by exposure to the FLR. This
stability may be due to the highly ordered packing of the alkyl
chains in the monolayer of Ti-11-hydroxyundecylphosphonate which
makes ether group .quadrature.-C--H bond abstraction sterically
difficult; such abstraction processes are believed to involve
oxygen-stabilized intermediate radicals, which may not be
conformationally accessible in the tightly packed film.
Example 39
Hydrolytic Stability of Modified Titanium Surfaces
[0285] For a surface modification technique to be viable for use in
vivo, the interface must be stable to hydrolysis under
physiological conditions. Current technologies using siloxanes are
limited: siloxane derivatized surfaces are hydrolytically labile.
Instability of the surface results in desorption of the
biomolecules from the surface, which may have deleterious effects
in vivo. It has been shown that in vivo tests of titanium surfaces
merely coated with bone morphogenic protein-2 (BMP-2) result in
encapsulation of the surface by fibrous tissue, which is then
coated in bone. It is postulated that desorption from the surface
leads to the observed encapsulation. Thus, stable covalent
attachment of the drug releasing agent to the surface is believed
to be important. The hydrolytic stability of phosphonate interfaces
on TiO.sub.2 and ZrO.sub.2 powders have been studied at neutral pH.
It was demonstrated that over the course of one week, 16% of bound
octadecylphosphonic acid was lost from the surface of TiO.sub.2 and
5% of bound material was lost from the surface of ZrO.sub.2, while
powders coated with octadecyldimethylchlorosilane showed almost
total surface hydrolysis over the course of one week.
[0286] To further test the stability of diphosphonate SAMs towards
aqueous conditions, fluorimetry was employed. Coupons of Ti-mPEG
were then exposed to vapor of DANSYL chloride to yield the
surface-bound complex. The complex modified coupons were then
treated with a solution of 6-maleimidohexanoic acid in THF and were
then rinsed thoroughly, and analyzed via IR (v.sub.CO.apprxeq.1705
cm.sup.-1). The coupons were then placed in a solution of
N-(5-dimethylamino-1-naphthyl-sulfonyl)-RGDC (DANSYL-RGDC), then
rinsed thoroughly, and probed via IR
(v.sub.peptide-CO.apprxeq.1650-1690 cm.sup.-1). The DANSYL group
provides a fluorescent "tag" with which to monitor hydrolysis of
the surface.
[0287] Fluorophore-labeled coupons were immersed in water at about
pH 7.5. Fluorescence intensity of the supernatant was measured over
about 90 hours; a calibration curve of DANSYL-RGDC was also
prepared to relate concentrations in solution with fluorescence
intensity, according to Beer's Law. After about 96 hours, the
coupons were exposed to a strongly alkaline solution (about pH 12)
to completely hydrolyze any remaining zirconium complex from their
surface. Fluorescence intensity in the supernatant was measured
against a second calibration curve of DANSYL-RGDC at about pH 12,
and the solution concentration was determined by Beer's Law. In
this way it was shown that the phosphonate film has long term
hydrolytic stability at about pH 7.5. During the first 90 minutes,
desorption of multilayered peptide occurs. Following the first 90
minutes, little further desorption occurred, even over about 4 days
(see FIGS. 4(a) and 4(b)). At this point, the DANSYL-RGDC remaining
on the surface was measured by exposing the coupon to strong
alkaline (about pH 12) for about 3 hours to cleave any remaining
zirconium complex species from the SAM. After this treatment, the
fluorescence intensity of the supernatant increased dramatically.
Analysis showed the surface loading of DANSYL-RGDC stable at about
pH 7.5 to be about 0.58 nmol/cm.sup.2 (the surface area of the
coupon was about 2.65 cm.sup.2). This value is similar to RGDC
loadings on SAMs of 11-hydroxyphosphonate on Ti (.about.0.52
nmol/cm.sup.2). Thus, the diphosphonate layered system, for every
link of the chain, is stable to aqueous conditions over the long
term, which is essential for use in biomaterials.
Example 40
X-Ray Photoelectron Spectroscopy (XPS) of Modified Titanium
Surfaces
[0288] X-ray photoelectron spectroscopy (XPS) is a powerful
technique to analyze the chemical composition of a surface, and XPS
spectra of phosphonates bound to the surfaces of various oxides
have been measured. In cases involving alkylphosphonates bound to
tantalum or titanium oxides, a single P(2p) signal was detected,
evidence of a single phosphorus species on the surface, the
surface-bound phosphonate. SAMs of
Ti-12-phosphonododecylphosphonate were also investigated via XPS
which revealed P(2s).apprxeq.192.0 eV with a shoulder at 193.3 eV
(the P[2s] signal was analyzed instead of P[2p] due to the
inability to resolve P[2p.sub.3/2] and P[2p.sub.1/2] of either a
surface bound or free phosphonate). The peak at lower binding
energy is indicative of a free phosphonic acid (c.f. the
diphosphonic acid powder). The shoulder at higher binding energy is
indicative of a surface-bound phosphonate (c.f. .about.192.5 eV
based on bona fide Ti-Phosphate film). The difference in the
measured intensities of the two phosphorus species is attributed to
the escape depth-based sensitivities of the surface bound species
which attenuates the signal of the surface bound phosphorus
photoelectron.
Example 41
Mixed Speciation Self Assembled Monolayers of Phosphonates (SAMP)
with Compositional and Spatial control: Patterning
[0289] In this embodiment of the invention, a basic SAMP coating is
functionalized with a maleimido coupling reagent to give 3 as shown
in FIG. 5.
[0290] The water wetting contact angle for 3 is .about.70.degree.
(the surface does not completely wet), and dithiothreitol (DTT) is
water soluble, so an aqueous solution of DTT will not spread out on
the surface of 3. Stamping DTT from aqueous media onto 3 is done
using masking or microcontact printing to lay down a pattern of DTT
on the micron scale (sub-cellular dimension). The mask is then
removed and the DTT-patterned surface is treated derivatized with
desirable species.
[0291] To verify the patterning, the surface is treated first with
DANSYL-RGDC (fluoresces green) and then with maleimido-derivatized
ALEXA-FLUOR.RTM.-cadaverine. Then the printed peptides may be
visualized by fluorescence microscopy to verify congruence between
the printed and designed patterns. See FIG. 6.
[0292] It will be understood that this method allows for
essentially unlimited spacial variation of surface patterning with
peptides or other organic species by varying the pattern and size
of holes in the mask. It will be further understood that the gaps
in the mask may be any type of shape or combination of shapes.
Example 42
Hip Implant
[0293] The surface of a surgically implanted artificial hip
encounters multiple environments for which different surface
properties and functionality is desirable. These areas where
different surface environments exist, as shown in FIGS. 7 and 8
are: The femoral stem (Region 1); the neck (Region 2); the head
(Region 3); the interior surface of the acetabular cup (Region 4a)
and the exterior surface of the acetabular cup (Region 4b). The
surface environment and desirable properties for each of these
regions are described below.
[0294] Region 1--When implanted, the surface of the femoral stem is
placed in contact with the bone and marrow of the femur. For this
surface, cell specific adhesion of osteoblasts is desirable to
promote osteoconductivity and enable rapid and strong fixation
between the native bone and the femoral stem surface.
[0295] Region 2--The neck of the implant connects the femoral stem
to the head. The neck does not contact bone or metal, but rather
muscle and blood. As such, desirable surface properties for the
neck are resistance to corrosion, cell non-adherence or
anti-inflammation.
[0296] Region 3--The ball or head of a hip implant sits against the
interior surface of the acetabular cup. To enable movement of the
leg, these surfaces should freely move against one another. For
these surfaces, osteoconductivity is not desirable. Rather, the
ideal surface will resist wear and abrasion and provide lubrication
for the interface between the ball and acetabular cup.
[0297] Region 4--The acetabular cup contacts bone on its exterior
convex surface (Region 4a) and the head of the hip stem on its
interior convex surface (Region 4b). In some cases, a lining
surface is placed on the interior surface of the acetabular cup.
This lining may be ceramic or ultra-high molecular weight
polyethylene. Therefore, the ideal surface properties for Region 4a
are the same as for Region 1 and the ideal surface properties for
region 4b are the same as for Region 3.
[0298] In one embodiment of the invention, Region 1 and Region 4a
of a titanium hip implant are coated with phosphonoundecanol to
which an osteoconductive molecule such as a peptide containing the
RGD moiety is attached. Region 2 is coated with underivatized
11-hydroxyundecylphosphonate to prevent leaching of metals. Regions
3 and 4b are coated with octadeclphosphonic acid to lubricate the
interface between the ball and interior surface of the acetabular
cup and to minimize wear debris generated from abrasion at the
interface between the surfaces. In another embodiment, Region 2 is
coated with an anti-infective. TABLE-US-00007 TABLE 7 Embodiment
Region Desired Property Coating 1 1, 4a Osteoconduction 11-
hydroxyundecylphosphonate- RGDC 2 Anti-corrosion 11-
hydroxyundecylphosphonate 3, 4b Resistance to octadeclphosphonic
acid wear & lubrication 2 1, 4a Osteoconduction 11-
hydroxyundecylphosphonate- RGDC 2 Anti- 11- infection/anti-
hydroxyundecylphosphonate- microbial anti-microbial 3, 4b
Resistance to octadecyl phosphonic acid wear & lubrication
Example 43
Thickness Calculations for Phosphonate Coatings
[0299] The phosphonate coatings may be covalently bound to the
coated substrate via a mono-dentate, bi-dentate or tri-dentate
bound phosphonate. The thickness of the coating ranges from about
0.3 nm to at least about 100 nm depending on the length of the R
group bound to the phosphonic acid having the formula
H.sub.2RPO.sub.3. Actual ranges and values of coating thicknesses
depend on the type or content of the R groups of the phosphonate
coating and include coating thicknesses of about 0.3 nm to about
1.0 nm, about 1.0 nm to about 1.6 nm, about 1.6 nm, about 1.5 nm to
about 2.2 nm, about 2.0 nm, about 2.2 nm, about 2.2 nm to about 4.0
nm, about 2.5 nm to about 5.0 nm, about 2.8 nm, about 3.0 nm to
about 10.0 nm, about 6.0 nm, about 5 nm to 100 nm.
[0300] Example coating thicknesses are presented in Table 8.
Thicknesses were calculated in both solution and gas phase using
Chem3D and Gaussian minimizations, assuming a 33.degree. tilt angle
for bi-dentate phosphonate coatings. The example coatings in Table
8 are for illustrative purposes and do not define or limit the
scope of the invention. In addition, one of ordinary skill in the
art will appreciate that similar calculations can be made for
phosphonate coatings not list in Table 8 and will further
appreciate that the coating thickness may vary as a function of the
solvent and the number of phosphonate bonds (mono- bi- or
tri-dentate). TABLE-US-00008 TABLE 8 Phosphonate Coating
Thicknesses Phosphonic Acid Thickness (nm) H.sub.2RPO.sub.3 where R
is an alkylene or arylene hydrocarbon About 0.3-1.0 ligand
comprising between about 1 and 6 carbon atoms H.sub.2RPO.sub.3
where R is an alkylene or arylene hydrocarbon About 1.0-1.6 ligand
comprising between about 7 and 12 carbon atoms.
11-hydroxyundecylphosphonic acid 1.6 H.sub.2RPO.sub.3 where R is an
alkylene or arylene hydrocarbon About 1.5-2.2 ligand comprising
between about 13 and 18 carbon atoms 11-hydroxyundecylphosphonic
acid-maleimide 2.0 Octadecyl phosphonic acid 2.2 H.sub.2RPO.sub.3
where R is an alkylene or arylene hydrocarbon About 2.2-4.0 ligand
comprising between about 19 and 40 carbon atoms H.sub.2RPO.sub.3
where R contains a peptide or poly-petide. About 2.5-5.0
11-hydroxyundecylphosphonic acid-maleimide-RGDC 2.8
H.sub.2RPO.sub.3 where R is a functional group (e.g 11- About
3.0-10.0 hydroxyundecylphosphonic acid) linked to a globular
peptide or protein via maleimide or other peptide linker.
H.sub.2RPO.sub.3 where R contains a globular peptide or protein
About 3.0-10.0 11-hydroxyundecylphosphonic acid-maleimide-IgG About
6.0 H.sub.2RPO.sub.3 where R contains a polymer About 5-100
11-hydroxyundecylphosphonic acid-methyl-terminated About 100
poly(ethylene glycol)
Example 44
In-Vivo Osteoconductivity of RGD-Phosphonate-Functionalized
Implants
[0301] Stable osteoconductive surfaces are desirable on orthopedic
implants. An in-vivo study was conducted to assess the stability
and osteoconductivity of a functionalized phosphonate coated
orthopedic implant surface.
[0302] Sixty-two male Sprague-Dawley rats (Harlan, Ind., USA), 12
weeks of age with an average mass of 382.+-.41 grams (range 285 to
466 grams), were bilaterally implanted in the femoral medullary
canal of the femur. An RGDC/Au-functionalized smooth titanium
implant (15.0 mm.times.1.6 mm), which served as control, was
implanted in one femur and an RGD-SAMP functionalized smooth
titanium implant prepared according to the present invention was
implanted in the contralateral femur.
[0303] Titanium alloy (Ti-6Al-4V) rods, 1.6 mm in diameter, were
hand-sanded using sand paper coated with 240, 500, 800, and 1200
grit SiC. For the control group (RGDC/Au), the rods were washed
with sonication in dichloromethane (30 minutes), then methyl ethyl
ketone (30 minutes), and then methanol (three 15 minute intervals).
They were then coated using an Edwards Coating System at reduced
pressure. A layer of chromium (.about.100 .ANG.) was deposited,
followed by a layer of gold (.about.1000 .ANG.). Thickness of the
deposited layers was monitored using a QCM crystal located within
the evaporating chamber. The rods were, then cut into 15.0 mm pins
and cleaned by washing with sonication in acetone (45 minutes),
followed by the solvent washing regimen as described above. After
solvent cleaning, all samples were placed in an oven at 120.degree.
C. for at least an hour or until needed. Following, the pins were
immersed in a 0.5 mM solution of RGDC-peptide (Arg-Gly-Asp-Cys) in
MilliQ water with final solution pH of 6.5. Containers were
covered, and the pins were allowed to react with the RGDC for
twenty-four hours with stirring. The pins were then rinsed briefly
with sonication in MilliQ water and were blown dry with
nitrogen.
[0304] For the experimental group (RGD/SAMP), the rods were first
cut into 15.0 mm pins. The pins were cleaned by washing with
sonication in acetone (45 minutes), then by the solvent washing
regime as described above. All samples were placed in an oven at
120.degree. C. for at least an hour. Following, the pins were
suspended in a 0.1 mM solution of 11-hydroxyundecylphosphonic acid
(PUL) in THF. The solvent was allowed to evaporate at room
temperature until its level was below that of the ends of the
suspended pins. The pins were then heated in a gravity convection
oven at .about.130.degree. C. for 48 hours to bond the
self-assembled monolayer of the phosphonate. The pins were rinsed
with sonication in methanol for 30 minutes to remove any unbound
material and were then blown dry with nitrogen. The Ti-PUL pins
were immersed in a 0.5 mM solution of 3-maleimidopropionic acid
N-hydroxysuccinimide ester (MAL) in dry acetonitrile and were
stirred under nitrogen for 24 hours. They were rinsed with
acetonitrile, briefly with sonication, to remove any residual
uncoupled MAL and were then blown dry with nitrogen. Then the
Ti-PUL-MAL pins were immersed in a solution of RGDC, following the
same procedure as described above for the control pins.
[0305] After coating, all pins were sterilized with ethylene-oxide
(ETO) at 55.degree. C. for a period of 3 hours after which they
were kept in a stove for 10.5 hours to let the excess ETO fade off.
The pins were stored at room temperature.
[0306] Postoperative, immediate weight bearing was allowed. No
complications were encountered, and no animals were eliminated for
reasons of well-being. The animals were also administered bone
flurochromes, i.e., calcium chelators, over 2 distinct time
periods. Calcein (20 mg/kg) and tetracycline-HCL (20 mg/kg) were
administered subcutaneously at a perivascular location at base of
the tail to enable calculations of bone formation and
mineralization rates. Interlabeling periods were 7, 6 and 11 days,
for the 2, 4 and 8-week groups respectively. Twenty rats were
sacrificed at two, four and eight weeks after pin implantation for
biomechanical testing (n=10 at each time point) and
histomorphometrical analysis (n=10 at each time point). The femora
were harvested and cleaned of soft tissue. The specimens were
preserved by immersion in 70% ethanol, sectioned, and stained.
[0307] Histomorphometric analysis demonstrated that the RGD-SAMP
functionalized implants showed improved osteoconduction, bone
thickness and implant surface mineralization, particularly at the
early 2 week time point. At 8-weeks post-implantation bone
thickness increased 3.3-fold with the SAMP-coated pins (p<0.001)
and 1.9-fold with the control pins (p<0.05) compared to the
4-week time point. Also, mineralizing surface had a 1.6-fold
increase with the SAMP-coated pins (p<0.05) and a 2.2-fold
increase with the control pins (p<0.005) compared to 4-weeks
post-implantation.
[0308] Percentages of bone volume and bone-to-pin contact were
significantly affected by the pin coating. The bone volume was
significantly greater in the SAMP-coated pin at the 2 week time
point (p<0.05) but not for later time points (FIGS. 9(a) and
9(b)). The percent-tage of pin surface covered by bone was also
significantly greater with the SAMP-coating compared to control at
the 8-week time point, but not earlier time points (FIG. 10). The
percentage of bone volume decreased significantly by 8 weeks with
the SAMP-coated pins, while bone volume increased significantly
with the control pins by 4 weeks with a non-significant tendency to
decrease again by 8 weeks.
[0309] The histomorphometrical data suggest there is more active
bone remodeling occurring with the SAMP-platform than with the
conventional gold platform and there is significant effect of time
on the thickness of the layer of newly formed bone. There is a
greater amount of bone, albeit woven, present after 2 weeks with
the SAMP-platform than with the gold platform. This highly
trabecularized bone, albeit poor in quality, was more frequently
localized at the ends of the pin, either proximal, distal or both.
This greater amount of bone at 2 weeks suggests there is increased
promotion of attachment and/or activity of osteoblasts with the
SAMP-platform. However, this increased amount of bone is resorbed
away by 4 and 8 weeks. Present at 4 and 8 weeks are isolated bone
trabeculae aligned parallel and adjacent to the area previously
occupied by the pin. The reduction in trabecular density (i.e.
number) with time confirms a loss in connectivity and the absence
of bone bridging beyond the 2-week time point. There is nonetheless
a greater amount of bone in contact with pins with the
SAMP-platform compared to the gold platform at 8-weeks time.
[0310] Although the present invention is described with reference
to certain preferred embodiments, it is apparent that modification
and variations thereof may be made by those skilled in the art
without departing from the spirit and scope of this invention as
defined by the appended claims. In particular, it will be clear to
those skilled in the art that the present invention may be embodied
in other specific forms, structures, arrangements, proportions, and
with other elements, materials, and components, without departing
from the spirit or essential characteristics thereof. One skilled
in the art will appreciate that the invention may be used with many
modifications of materials, methods, and components otherwise used
in the practice of the invention, which are particularly adapted to
specific environments and operative requirements without departing
from the principles of the present invention. The presently
disclosed embodiments and examples are therefore to be considered
in all respects as illustrative and not restrictive, the scope of
the invention being indicated by the appended claims, and not
limited to the foregoing description.
[0311] The disclosures of all patents and publications mentioned
herein are hereby incorporated by reference in their entirety.
* * * * *