U.S. patent application number 10/635336 was filed with the patent office on 2004-02-12 for devices and methods for delivering a drug.
This patent application is currently assigned to Boston Scientific Corporation. Invention is credited to Chee, U. Hiram, Meuller, Richard.
Application Number | 20040030320 10/635336 |
Document ID | / |
Family ID | 22476559 |
Filed Date | 2004-02-12 |
United States Patent
Application |
20040030320 |
Kind Code |
A1 |
Chee, U. Hiram ; et
al. |
February 12, 2004 |
Devices and methods for delivering a drug
Abstract
The present invention provides for the needleless delivery of
selected agents to target tissues within a subject body by
providing the agents in one or more high-energy jets or streams
directed against selected wall or surface regions of such tissues.
One general embodiment of the apparatus includes (i) an elongate
jacket having (a) proximal and distal ends, (b) a lumen extending
between such ends, and (c) a blunt, distal-end face defining one or
more outlet ports in fluid communication with the lumen; (ii) an
introduction port for feeding such agent(s) into the lumen; and
(iii) a pump communicating with a proximal end of the jacket. The
pump is operable to generate an increased pressure within the lumen
such that an agent introduced therein will be propelled out of the
distal outlet port(s), thereby forming respective high-energy,
narrow, fluid jets or streams capable of penetrating a selected
tissue. In an exemplary use, wherein a patient's heart is treated
with an agent for transferring genetic information to the heart
tissue, the distal end of the jacket is positioned adjacent a
selected region of the heart wall, and high-energy fluid jets are
directed thereagainst in a manner effective to penetrate the wall,
thereby delivering the agent into the myocardium.
Inventors: |
Chee, U. Hiram; (Santa Cruz,
CA) ; Meuller, Richard; (Byron, CA) |
Correspondence
Address: |
PENNIE AND EDMONDS
1155 AVENUE OF THE AMERICAS
NEW YORK
NY
100362711
|
Assignee: |
Boston Scientific
Corporation
|
Family ID: |
22476559 |
Appl. No.: |
10/635336 |
Filed: |
August 6, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10635336 |
Aug 6, 2003 |
|
|
|
09585983 |
Jun 2, 2000 |
|
|
|
6641553 |
|
|
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|
60137265 |
Jun 2, 1999 |
|
|
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Current U.S.
Class: |
604/508 ;
604/537 |
Current CPC
Class: |
A61B 2018/00392
20130101; A61B 17/32037 20130101; A61M 37/0092 20130101; A61B
2017/00247 20130101; A61M 2025/0089 20130101; A61B 2017/00243
20130101 |
Class at
Publication: |
604/508 ;
604/537 |
International
Class: |
A61M 031/00 |
Claims
What is claimed:
1. An apparatus for delivering one or more selected diagnostic or
therapeutic agents to a target site within a selected body tissue,
comprising: an elongate jacket having (i) proximal and distal ends,
(ii) one or more lumens extending between said ends, and (Iii) a
substantially blunt, distal-end face defining one or more outlet
ports communicating with one or more of said lumens; with each of
said outlet ports having a diameter of about 0.025" or less; and a
pressure-control source adapted for fluid communication with one or
more of said lumens, said source being operable to establish an
elevated pressure within such lumen(s) such that an agent placed
therein will be propelled toward, and out of, one or more of said
outlet ports, thereby forming one or more respective fluid jets or
streams capable of penetrating a selected tissue disposed adjacent
thereto.
2. The apparatus of claim 1, wherein each of said outlet ports has
a central, longitudinal axis angled no greater than about 35
degrees in respect to a central, longitudinal axis of said jacket
at its distal end.
3. The apparatus of claim 1, wherein the central, longitudinal axis
of at least one of said outlet ports is oriented substantially
parallel to the central, longitudinal axis of said jacket at its
distal end.
4. The apparatus of claim 1, wherein said jacket is adapted to
withstand an internal pressure of at least about 300 psi along its
proximal end, and at least about 100 psi along its distal end.
5. The apparatus of claim 1, wherein at least two separate lumens
extend through said jacket, each distally terminating at a fluid
connection with at least one of said outlet ports.
6. The apparatus of claim 5, wherein said separate lumens are
defined by respective elongate tubes extending through said jacket,
with each tube having an internal passage with a diameter of from
about 0.010" to about 0.020".
7. The apparatus of claim 1, further comprising a plate-like member
mounted substantially transverse to a longitudinal axis of said
jacket at its distal-end region, with said plate-like member
defining said distal-end face; and one or more bores extending
through said plate-like member, with each bore defining one of said
outlet ports.
8. The apparatus of claim 1, further comprising an elongate
catheter sleeve having (i) proximal and distal ends and (ii) one or
more lumens between said ends; with one such lumen being adapted to
removably receive said jacket.
9. The apparatus of claim 8, wherein one of said lumens, other than
said jacket receiving lumen, defines a guidewire channel.
10. The apparatus of claim 9, wherein said jacket-receiving lumen
and said guidewire channel extend side-by-side from the proximal
end to the distal end of said sleeve.
11. The apparatus of claim 9, wherein (i) said jacket-receiving
lumen extends from the proximal end to the distal end of said
sleeve, and (ii) said guidewire channel is provided near a distal
end of said sleeve to enable use of said apparatus as a
rapid-exchange type catheter.
12. An apparatus for delivering one or more selected diagnostic or
therapeutic agents to a target site within a selected body tissue,
comprising: an elongate jacket having (i) proximal and distal ends,
(ii) a lumen at least along the distal end of said jacket, and
(iii) a distal-end face defining one or more outlet ports
communicating with said lumen; an agent-holding region adapted for
fluid communication with said lumen; and means for moving such aged
it(s) from said holding region and through said outlet port(s) in a
fashion effective to cause the agent(s) to penetrate a selected
tissue disposed adjacent thereto.
13. The apparatus of claim 12, for use with one or more agents
coated on a plurality of carrier micro-particles, wherein said
moving means includes a biolistic particle-delivery assembly
disposed along a distal-end region of said jacket.
14. The apparatus of claim 12, wherein said propelling means
includes an ultrasonic transducer disposed across said lumen along
a distal-end region of said jacket.
15. A method for delivering one or more selected diagnostic or
therapeutic agents to a target site within a selected body organ or
tissue, comprising: directing one or more fluid jets or streams
against a wall or surface of a selected, internal body organ or
tissue, with each jet or stream (i) carrying such agent(s), (ii)
having a maximum diameter of about 0.025", or less, as it contacts
the wall or surface, and (iii) having an energy sufficient to
permit the agent(s) to penetrate the organ or tissue to a depth of
at least about 2 mm.
16. The method of claim 15, wherein said directing step is effected
using an agent elongate jacket having (a) proximal and distal ends,
(b) one or more lumens extending between said ends, and (c) a
substantially blunt, distal-end its communicating with one or more
of said lumens; from said outlet port(s) against such wall or
surface.
17. The method of claim 16, wherein each jet or stream is formed by
propelling said agent(s) through at least a portion of said lumen
and out of one of said outlet ports under condition of an increased
pressure at said port of up to about 100 psi.
18. The method of claim 15, wherein at least one jet or stream is
directed substantially along a line angled no greater than about 35
degrees in respect to a line normal to such wall or surface.
19. The method of claim 15, wherein at least one jet or stream is
directed substantially along a line normal to such wall or
surface.
20. The method of claim 15, wherein the selected tissue is
myocardial tissue, and the selected agent is directed against an
endocardial wall, a septal wall, or an epicardial wall from a
distance no greater than about 5 mm from such wall.
Description
[0001] This is a continuation of application Ser. No. 09/585,983,
which claims priority to U.S. Provisional Application No.
60/137,265 filed Jun. 2, 1999, both of which are incorporated
herein by reference in their entirety.
FIELD OF THE INVENTION
[0002] The present invention is directed to an apparatus and method
for delivering selected therapeutic and/or diagnostic agents to
target sites in selected body tissues. More particularly, the
invention provides for the needleless delivery of such agents by
providing each agent in one or more high-energy jets or streams
directed against selected wall or surface regions of selected
tissues.
BACKGROUND OF THE INVENTION
[0003] Needles have long been popular for delivering therapeutic
and diagnostic agents into selected tissues. In a typical use, a
needle, having an axial lumen extending therethrough, is passed
through the wall of a selected tissue to a desired depth, and an
agent is then passed from a holding region (e.g., in a bag, or
syringe barrel), disposed in fluid communication with a proximal
end of the needle, through the axial lumen and out of the distal
end, into the tissue. Perhaps best known for their use in the
delivery of agents through the skin, needles have also been widely
employed in connection with catheters and endoscope-type devices
for delivering agents to various organs and tissues within the
body. For example, in a typical catheter-type device, an outer
jacket is configured for navigation through a patient's
vasculature, e.g., using a pull-wire mechanism operable to deflect
the distal-end region of the catheter, as desired. A reciprocally
movable shaft, disposed within the jacket, defines an
agent-delivery passage connected at its distal end to the proximal
end of an agent-delivery needle. By advancing the internal shaft,
an operator can cause the distal, pointed end of the needle to
pierce a selected region of tissue. An agent can then be passed
through the shaft's lumen, e.g., under pressure, to flow out of the
needle's distal end and into the tissue.
[0004] While convenient and effective for certain purposes, the use
of needles as injection devices is not without its disadvantages.
For example, tissue damage can occur in the region of needle
penetration. Also, as most needle-injection devices use only a
single needle, the delivery of an agent thereby is often highly
localized to one, relatively small region in the tissue (i.e., the
site occupied by the needle's distal end), thus limiting the
area/volume of tissue that can be treated with each delivery
operation. With particular regard to catheter-type needle-injection
devices, such as described above, axial reciprocation of the
needle-bearing shaft within the steerable jacket can be hampered,
if not entirely prohibited, in situations where the distal-end
region of the catheter must be deflected to a great degree, e.g.,
in efforts to reach remote regions via tortuous pathways of a
patient's vasculature, rendering such devices unsuitable for
certain applications.
SUMMARY OF THE INVENTION
[0005] One aspect of the present invention provides an apparatus
for delivering a selected diagnostic or therapeutic agent to a
target site within a selected body tissue, such as myocardial
tissue of the heart.
[0006] In one general embodiment, the apparatus includes an
elongate jacket having (a) proximal and distal ends, (b) one or
more lumens extending between such ends, and (c) a substantially
blunt, distal-end face defining one or more outlet ports
communicating with one or more of the lumens. Preferably, each
outlet port has a diameter of about 0.025", or less (e.g., from
about 0.00025" to about 0.020"). The apparatus further includes a
pressure-control source (e.g., a pump) adapted for fluid
communication with one or more of the lumens. The pressure-control
source is operable to establish an elevated pressure (e.g., up to
about 300 psi) within such lumen(s) such that an agent placed
therein will be propelled toward, and out of, one or more of the
outlet port(s), thereby forming one or more respective fluid jets
or streams capable of penetrating a selected tissue disposed
adjacent thereto.
[0007] The apparatus can further include one or more valves, such
as spring-loaded needle-type plungers or the like, each being
disposed at location along a distal region of a respective one of
the lumens for regulating fluid flow therethrough. The valves can
be manually operable, or they can respond automatically to one or
more selected events (e.g., reaching a threshold pressure at or
near a respective outlet port).
[0008] In one embodiment, at least one of the outlet ports has a
central, longitudinal axis angled no greater than about 35.degree.
in respect to a central, longitudinal axis of the jacket at its
distal end. In another embodiment, the central, longitudinal axis
of at least one of the outlet ports is oriented substantially
parallel to the central, longitudinal axis of the jacket at its
distal end. In a further embodiment, one or more outlet ports are
configured to provide "side firing" fluid jets or streams.
[0009] The structure defining each lumen is configured to withstand
an elevated pressure generated in the lumen. For example, in one
embodiment, where the jacket defines a lumen, the jacket is adapted
to withstand an internal pressure of at least about 300 psi along
its proximal end, and at least about 100 psi along its distal
end.
[0010] The pressure-control source can be a pump, such as a power
injector or a hand-operable inflation device. Preferably, the
pressure-control source is adapted to generate an internal pressure
at a distal end of said jacket, proximate said outlet ports, of at
least about 20 psi.
[0011] One embodiment of the apparatus incorporates the invention
in a catheter-type device. For example, the jacket can be a
flexible catheter-jacket, including a steerable distal-end region
that can be deflected in a manner permitting navigation through the
vasculature of a subject body so that the outlet port(s) can be
positioned adjacent a wall or surface region of a selected tissue
or organ. Or, the catheter-type device can include a fixed shape
(bend) at along its distal end to facilitate navigation. In yet
another embodiment, a first steerable catheter is slidably
maintained within an axial lumen of a second steerable catheter.
Another embodiment of the apparatus incorporates the invention in
an endoscope-type device. Another embodiment of the apparatus
incorporates the invention in an open surgical tool having a bent
head to access occluded regions of the tissue to be treated. In yet
another embodiment, a portion of the proximal end of the jacket is
substantially rigid, while a portion of the elongate jacket at the
distal end is substantially flexible and either bendable or
steerable. The distal end of the jacket may also have one or more
force contact transducers.
[0012] Any reasonable number of lumens can extend through the
jacket of the apparatus. In one exemplary construction, at least
two separate lumens extend through the jacket, each distally
terminating at a fluid connection with at least one outlet port.
For example, two or more separate lumens can be defined by
respective elongate tubes extending through the jacket, with each
tube having an internal passage with a diameter of from about
0.010" to about 0.020". Advantageously, this configuration reduces
the dead volume in the system. Also, the "on/off" response is
optimized, and the pressure limit requirement for the conduit can
be readily met.
[0013] The distal-end face of the jacket is defined, in one
embodiment, by a plate-like member mounted substantially transverse
to a longitudinal axis of the jacket at its distal-end region.
Further in this embodiment, one or more bores extend through the
plate-like member--each defining an outlet port. In an exemplary
construction, the plate-like member is formed of a suitable,
non-reactive metal; and the bores are formed by laser drilling,
and/or photo-chemical machining.
[0014] In one embodiment of the invention, the apparatus is
embodied in a catheter-type assembly. An elongate catheter sleeve
is provided, with the catheter sleeve having (i) proximal and
distal ends, and (ii) one or more lumens between such ends. For
navigation, the catheter sleeve can incorporate a fixed shape at
its distal region, and/or it can incorporate a pull-wire steering
mechanism. One of the lumens, in this embodiment, is adapted to
removably receive the jacket.
[0015] According to one embodiment, the jacket-receiving lumen is
further adapted to serve as a guidewire channel, when the jacket is
removed therefrom.
[0016] In another embodiment, one of the lumens, other than the
jacket-receiving lumen, defines a guidewire channel. In one
exemplary arrangement, the jacket-receiving lumen and the guidewire
channel extend side-by-side from the proximal end to the distal end
of the catheter sleeve. In another exemplary arrangement, (i) the
jacket-receiving lumen extends from the proximal end to the distal
end of said sleeve, and (ii) the guidewire channel is provided near
a distal end of the catheter sleeve to enable use of the apparatus
as a rapid exchange type catheter.
[0017] One embodiment of the catheter-type apparatus further
includes means for maintaining the distal end of the jacket at the
selected target site within a patient's body while one or more
high-energy fluid jets or streams are being directed
thereagainst.
[0018] A further aspect of the present invention provides an
apparatus for delivering one or more selected diagnostic or
therapeutic agents to a target site within a selected body tissue,
including (i) an elongate jacket having (a) proximal and distal
ends, (b) a lumen at least along the distal end of said jacket, and
(c) a distal-end face defining one or more outlet ports
communicating with said lumen; (ii) an agent-holding region (e.g.,
a chamber) adapted for fluid communication with said lumen; and
(iii) means for moving such agent(s) from said holding region and
through said outlet port(s) in a fashion effective to cause the
agent(s) to penetrate a selected tissue disposed adjacent
thereto.
[0019] In one embodiment, for use with one or more selected agents
(e.g., DNA) coated on a plurality of carrier particles (e.g., gold
particles), the moving means includes a biolistic particle-delivery
or bombardment assembly disposed within a distal-end region of said
jacket.
[0020] In another embodiment, the propelling means includes an
ultrasonic transducer disposed across the lumen along a distal-end
region of the jacket.
[0021] In yet another of its aspects, the present invention
provides a method for delivering one or more selected diagnostic or
therapeutic agents to a target site within a selected body organ or
tissue. One general embodiment of the method includes the step of
directing one or more fluid jets or streams against a wall or
surface of a selected, internal body organ or tissue, with each jet
or stream (i) carrying such agent(s), (ii) having a maximum
diameter of about 0.025", or less, as it contacts the wall or
surface, and (iii) having an energy sufficient to permit the
agent(s) to penetrate the organ or tissue to a depth of at least
about 2 mm (preferably about 3-10 mm).
[0022] According to one embodiment, a gas is utilized as a partial
injectate. For example, a gas can be included with one or more of
the fluid jets or streams carrying one or more selected agents, or
it can be directed therein from a secondary port. In one preferred
embodiment, the gas is absorbable by the selected body organ or
tissue. The gas, which can include, for example, CO2, can act as a
good accelerator. In a preferred embodiment, the agent, such as a
nucleic acid, is carried on micro-particles.
[0023] The method, as just set forth, can be effected using an
agent-delivery apparatus comprised of an elongate jacket having (a)
proximal and distal ends, (b) one or more lumens extending between
such ends, and (c) a substantially blunt, distal-end face defining
one or more outlet ports communicating with one or more of the
lumens. The agent or agents are directed from the outlet port(s)
against such wall or surface. In one embodiment, each jet or stream
is formed by propelling the agent(s) through at least a portion of
the lumen and out of one of the outlet ports under condition of an
increased pressure at the port (e.g., up to about 100 psi; and
preferably between about 20-30 psi).
[0024] One or more of the jets or streams can be directed
substantially perpendicular to a wall or surface of the selected
tissue, and/or they can be directed at an angle (e.g., no greater
than about 35.degree. in respect to a line normal to a wall or
surface of the tissue).
[0025] In one embodiment, the selected tissue is myocardial tissue,
and the selected agent is directed against an endocardial wall, a
septal wall, or an epicardial wall from a distance no greater than
about 5 mm from such wall. Any desired agents can be employed
(e.g., nucleic acids, proteins, etc.). For example, one or more
agents can selected for desirable angiogenic properties. In one
particular embodiment, the selected agent includes naked DNA.
[0026] These and other features and advantages of the present
invention will become clear from the following description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The structure and manner of operation of the invention,
together with the further objects and advantages thereof, may best
be understood by reference to the following description taken in
conjunction with the accompanying drawings, in which:
[0028] FIG. 1 illustrates a steerable catheter-type device for
delivering selected diagnostic and/or therapeutic agents to target
sites within a selected body tissue using high energy jets, in
accordance with an embodiment of the present invention;
[0029] FIG. 2A is an enlarged, side-sectional view of a distal-end
region of the device shown in FIG. 1;
[0030] FIG. 2B shows the device of FIGS. 1 and 2A being used to
direct four high energy jets carrying one or more selected
therapeutic and/or diagnostic agents through a wall of a selected
body organ and into the tissue;
[0031] FIG. 3 is an exploded view of the apparatus of FIGS.
2A-2B;
[0032] FIG. 4 is a partial, side-sectional view of a further
embodiment of an agent delivery apparatus for delivering selected
diagnostic and/or therapeutic agents to target sites within a
selected body tissue using high-energy jets, according to the
teachings of the present invention;
[0033] FIG. 5 shows the distal-end region of a steerable
catheter-type device for delivering selected diagnostic and/or
therapeutic agents to target sites within a selected body tissue
using ultrasonic energy, according to one embodiment of the present
invention;
[0034] FIG. 6 shows, in partial side-sectional view, an exemplary
agent-delivery port and a secondary drug or gas port that meets the
delivery port at an angle, as well as several exemplary jet or
spray patterns;
[0035] FIG. 7 is a partial side view, with portions shown in
section, of an exemplary valving mechanism operable to regulate
fluid flow through an agent-delivery lumen and/or outlet port;
and
[0036] FIG. 8 shows a portion of a steerable catheter positioned
with its distal end adjacent a target region of an endocardial wall
of a patient's left ventricle, with the catheter being adapted to
maintain its distal end at such position notwithstanding
"action-reaction" forces due to high-energy jets emanating
therefrom that would tend to push it away from the wall.
[0037] FIG. 9 is a partial side view of an example of the invention
as it is placed near a tissue (9a), urged against the tissue (9b)
thus creating a contact force between the device and the tissue,
the application of hydraulic force causing ejection of a fluid
stream from each outlet port thus propelling the fluid into the
tissue (9c), and the removal of hydraulic force and the retention
of fluid by the tissue within pockets created by hydraulic erosion
(9d).
[0038] FIG. 10a illustrates an example of the invention where a the
device is conveyed to the target tissue via a steerable catheter
with having an axial lumen where the device is slidably directed
towards the target tissue. FIG. 10b illustrates how the device is
"steered" towards a target.
[0039] FIG. 11 illustrates an example of the invention where the
device is combined with a steerable catheter in one structure.
[0040] FIG. 12 illustrates an example of the invention where the
device is combined with a first steerable catheter in one structure
which resides in a second steerable catheter having an axial lumen
where the first steerable catheter is slidably maintained.
DETAILED DESCRIPTION OF THE INVENTION
[0041] The following discussion of the preferred embodiments of the
present invention is merely exemplary in nature. Accordingly, this
discussion is in no way intended to limit the scope of the
invention.
[0042] With initial reference to FIG. 1, a catheter assembly,
indicated generally by the reference numeral 12, includes a hand
unit 14 attached to a steerable catheter shaft or jacket 16 having
a controllably deflectable distal-end portion, as at 16a. Steering
of the catheter assembly can be accomplished in a variety of ways.
For example, the catheter assembly can include steering components
like those disclosed in U.S. Pat. No. 5,876,373, entitled
"Steerable Catheter," to Giba et al.; and/or in co-pending U.S.
patent application Ser. No. 09/080,175, filed May 16, 1998,
entitled, "Drug Delivery Module," to Glines et al.; and/or in
published European Patent Application No. EP 0 908 194 A2; each of
which is incorporated entirely herein by reference. In one
exemplary arrangement, a conventional pull wire (not shown) is
secured at a distal tip of the jacket and extends through a
wire-guide channel, formed longitudinally through a sidewall of the
jacket, to the hand unit, whereat the wire's proximal end is
coupled to a deflection or steering actuator assembly. Rotation of
a deflection knob, such as 20, which is threadedly mounted along a
forward end of the hand unit, causes the pull wire to be pulled
backward, and/or the jacket to be pushed forward, relative to one
another, thereby inducing deflection of the distal end of the
jacket. Rather than running the pull wire through a channel
extending through a sidewall of the jacket, another embodiment
provides the pull wire extending longitudinally along an interior
sidewall of the jacket. An advantage of the steerable catheter
embodiment of the present invention over Giba's steerable catheter
is the omission of the third inner tool, housed within the second,
steerable catheter of Giba. The present invention provides for a
unified structure of the tool and steerable catheter making the
device simpler, more easily operated, and less costly to
manufacture than Giba's triaxial, or coaxial arrangement. Another
embodiment of the invention provides for a single catheter unified
system where the jet device is integrated into a steerable catheter
and omitting the outer, non-steering sheath catheter of Giba,
discussed above. Alternatively, the inner tool or fiber optic of
Giba may be omitted resulting in a steerable catheter slidably
housed within an outer sheath. Other navigation mechanisms and
arrangements, suitable for use herein, will be apparent to those
skilled in the art. For example, the catheter shaft or jacket can
be configured with a fixed shape (e.g., a bend) at its distal end
to facilitate navigation as described in application Ser. No.
08/646,856 by Payne filed May 8, 1996, entirely incorporated by
reference herein. Another embodiment of the present invention
provides for an arrangement that include a dual steering mechanism
where both the inner and outer catheter are steerable with either
or both catheters steering as a result of either or both having a
pull wire or a pre-shaped member. FIG. 11 illustrates a double
steerable catheter device 1100, having a first outer steerable
catheter 1102 slidably housing a second inner catheter 1104 having
a jet discharge tip 1106 located on its distal end 1108.
[0043] Jacket 16 is dimensioned to be placed in the vasculature of
a subject and navigated therethrough until the distal tip is
disposed proximate a surface or wall region of a selected tissue or
organ, e.g., within about 5 mm from a surface within a heart
chamber (such as the endocardial wall within the heart's left
ventricle). The outer diameter of the catheter jacket is not
critical, provided only that it can be navigated to a desired site
within a subject body. Suitable catheter jackets range in size, for
example, from about 3 French to about 9 French. One preferred
catheter jacket is 7 French. Suitable catheter jackets are
available commercially, for example as guiding catheters and
diagnostic catheters from Bard Cardiology; Cordis; and Schneider
Worldwide. Certain preferred jackets from such sources include
fixed shapes at their distal end, instead of pull-wire steering
mechanisms.
[0044] Visualization enhancement aids, including but not limited to
radiopaque markers, tantalum and/or platinum bands, foils, and/or
strips may be placed on the various components of the catheter
assembly, including on the deflectable end portion 16a of catheter
jacket 16. In one embodiment, for example, a radio-opaque marker
(not shown) made of platinum or other suitable radio-opaque
material is disposed adjacent the distal tip for visualization via
fluoroscopy or other methods. In addition, or as an alternative,
one or more ultra-sonic transducers can be mounted on the catheter
jacket at or near its distal tip to assist in determining its
location and/or placement (e.g., degree of perpendicularity) with
respect to a selected tissue in a subject, as well as to sense wall
contact with, and/or wall thickness of, the tissue. Ultra-sonic
transducer assemblies, and methods of using the same, are
disclosed, for example, in published Canadian Patent Application
No. 2,236,958, entitled, "Ultrasound Device for Axial Ranging," to
Zanelli et al., and in co-pending U.S. patent application Ser. No.
08/852,977, filed May 7, 1997, entitled, "Ultrasound Device for
Axial Ranging," to Zanelli et al., each of which is incorporated
entirely herein by reference. In one embodiment, for example, two
transducers are angle mounted at the distal tip of the catheter
shaft in the axis or plane of pull-wire deflection. This
construction permits an operator to determine, by comparing signal
strength, whether the catheter tip region is perpendicular to a
selected tissue surface or wall. Additionally, this two-transducer
arrangement provides an operator with information useful for
determining an appropriate adjustment direction for improving
perpendicularity, as compared to single-transducer arrangements
that, while capable of indicating perpendicularity by signal
strength amplitude, are generally incapable of indicating a
suitable direction in which to move the tip to improve
perpendicularity. In a related embodiment, third and fourth
transducers (not shown) are added, off of the deflection axis, to
aid an operator with rotational movement and rotational
perpendicularity in the non-deflecting plane of the subject tissue
surface. Additional details of the just-described embodiment are
provided in co-pending U.S. patent application Ser. No. 09/566,196
[Attorney Docket No. 5756-0005.30], filed May 5, 2000, entitled,
"Apparatus and Method for Delivering Therapeutic and Diagnostic
Agents," to R. Mueller; incorporated entirely herein by reference.
Ultrasonic transducers may, preferably, be substituted with one or
more force contact transducers as described in co-pending U.S.
Provisional Patent Application No. 60/191,610 [Attorney Docket No.
5756-0011], filed Mar. 23, 2000 by Tom, entirely incorporated by
reference herein.
[0045] With respect to hand held, open surgery devices, it is often
important to insure that proper contact force is created between
the device and a target tissue before discharging the device.
Otherwise, the device may inadvertently discharge as it is
manipulated towards a target tissue, or it may, in the case where
too much force is applied, cause perforation of a tissue that is
thinned out as a result of distention caused by excessive force. A
force sensing interlock may be incorporated into the invention thus
only permitting discharge when such force is within a certain
range, both minimally and maximally. For example, ultrasound
transducers, force contact transducers, and mechanical interlocks
having a minimal and maximal limit. Consequently, hand held
needleless hypodermic injector devices, such as those described in
U.S. Pat. Nos. 3,057,349, 3,859,996, 4,266,541, 4,680,027,
5,782,802, each entirely incorporated by reference herein, lacking
interlocks altogether, or only providing interlocks that activate
at a minimum threshold force, without regard to a maximum force
limit, are often inadequate. These handheld needleless injectors
are further limited in that their structure is not amenable for use
inside of a patient cavity created by open surgery, thoroscopic or
other "portal" procedures. For example, in each of those
disclosures provided for a snub nosed hand-held gun for use against
a patients skin, typically a shoulder region of a human. The
present invention provides for an elongated jacket portion of the
tool to facilitate reaching inside a remote region of the patient.
The tool distal end may further be angled or bent, either fixedly,
or by bending on demand, or by remote steering of the distal region
of the tool. FIG. 12 illustrates an open surgical tool where device
1200 has an elongated jacket portion 1202 having a bend portion
1204, ending in jet tip 1206 located at distal end 1212 which is
where liquid is ejected when actuator 1208 is compressed thereby
causing a liquid reservoir located around 1210 to deliver fluid to
tip 1206 through a fluid conduit not shown.
[0046] Internal to the jacket is one or more lumens, extending
between the jacket's distal and proximal ends. The lumens serve as
passages through which one or more selected agents can pass en
route to a selected tissue or organ. In the arrangement of FIGS.
2A, 2B and 3, for example, a single lumen, denoted as 22, extends
longitudinally through jacket 16. In another embodiment, shown in
FIG. 4, a plurality of elongate tubes, such as 24a-24d, extend
through a primary lumen 22 defined by the jacket 16. In this latter
embodiment, each of the tubes includes an internal longitudinal
conduit or channel, defining a respective sub-lumen or delivery
lumen through which one or more agents can pass. Advantageously,
this configuration reduces the dead volume in the system. Also, the
"on/off" response is optimized, and the pressure limit requirement
for the conduit can be readily met.
[0047] Catheter jacket 16 terminates at a distal-end face,
indicated generally at 26, defining one or more narrow outlet ports
or orifices, such as 28a-28d (FIG. 3). Face 26 is configured with a
relatively broad distal surface region of sufficient area to
accommodate a desired number of outlet ports such that each port
can be placed against, or very close to (e.g., within, about 5 mm,
and preferably within about 2 mm), a selected wall or surface
region of a target body organ or tissue. Accordingly, one
embodiment provides the distal end face as a generally blunt
structure with a broad distal surface. For example, in FIGS. 2-4, a
cylindrical plate 32 defines the distal-end face, with the plate
having a distal surface that is substantially planar.
Alternatively, the distal surface can be somewhat curved (e.g.,
convex). One or more bores extend through the plate, between its
proximal and distal broad surfaces, defining outlet ports for the
passage of selected agents.
[0048] The plate can be secured along the distal-end region of the
jacket in any suitable manner. In one embodiment, for example, the
plate is attached directly to the distal tip of the jacket, or in a
counterbore formed from the distal tip. Another embodiment, shown
in FIGS. 2-4, contemplates the use of an intermediate adapter plug
or cap, denoted as 34, having a proximal end configured to fit
snugly over the outer circumference of a distal-end region of
jacket 16. The distal portion of the adapter cap includes an
annular counterbore, or stepped region, configured to receive a
peripheral region of the plate. Adapter cap 34 can be formed of a
suitable plastic material, such as polyethylene or nylon, or of a
metallic material such as stainless steel, and bonded to the jacket
by heat sealing and/or a conventional adhesive, or other bonding
means. The outlet port(s) can be formed, for example, by laser
boring, photo-chemical machining, or other suitable technique; or
the plate and bores can be formed together as a molded
component.
[0049] With further regard to the outlet ports, each is adapted for
communication with one or more of the agent-delivery lumens
extending through the jacket. In a preferred embodiment, there from
about 1-12 outlet ports (e.g., four, in the illustrated
arrangement), each having a diameter of no greater than about
0.025"; and preferably within a range of from about 0.00025" to
about 0.020" (e.g., 0.006"). The size and orientation of each
outlet port serves to direct agents passed through the catheter
lumen(s) in an axial direction, or at an angle no greater than
about 35 degrees off axis (i.e., relative to the catheter's
longitudinal axis at its distal-end region), in the form of a
narrow jet or stream. Axially directed jets or streams can help to
maximize penetration depth, while angled jets or streams can help
to increase the treated area/volume of tissue. Axially directed
jets are illustrated in FIG. 2B, wherein four outlet ports are
configured to direct an agent passed through lumen 22 (indicated by
the large, darkened arrow) axially into a selected tissue 28 as
four separate jets or streams (indicated by the four smaller,
substantially parallel arrows).
[0050] The outlet ports can be configured to achieve desired jet or
spray patterns by modifying, for example, the port diameter, length
and/or internal shape. The pressure at the port can also be
adjusted to influence the patterns. Injection streams can be
further modified with secondary injection of additional drug, or a
compatible gas, such as CO.sub.2 and/or other absorbable gas. Such
a gas can be a good accelerator. In addition, a pulsed injection
pattern can be employed to capitalize on tissue recoil effects. In
these regards, attention is directed to FIG. 6 which shows an
exemplary agent-delivery port 68 and a secondary drug or gas port
72 that meets the delivery port 68 at an angle. Also depicted are
several exemplary jet or spray patterns, denoted as "A," "B" and
"C." Pattern "A" can be achieved by passing an agent through port
68 under pressure, without the use of a secondary port. Pattern "A"
is modified to that of pattern "B" by additionally passing an agent
or gas through secondary port 72. Pattern "C" is a pulsed spray
pattern that can be used to take advantage of tissue recoil
effects. This pattern can be achieved by passing an agent through
port 68 as rapid, controlled bursts, without the use of a secondary
port. FIG. 9 is a partial side view of an example of the invention
as it is placed near a tissue (9a), urged against the tissue (9b)
thus creating a contact force between the device and the tissue,
the application of hydraulic force causing ejection of a fluid
stream from each outlet port thus propelling the fluid into the
tissue (9c), and the removal of hydraulic force and the retention
of fluid by the tissue within pockets created by hydraulic erosion
(9d).
[0051] In one embodiment, one or more of the agent-delivery lumens
and/or outlet ports includes a valving mechanism operable to
regulate fluid flow therethrough. Such an arrangement can be
useful, for example, for controlling the timing and/or energy of
each jet. For example, a quick-action valve can permit controlled,
rapid-fire bursts from an outlet port. In one embodiment, a first
burst causes a target tissue to recoil and expand, and a subsequent
burst then penetrates the tissue while in an expanded state. An
exemplary valving mechanism is shown in FIG. 7. Here, an elongate
needle plunger 80 has a distal, pointed end 82 that is normally
urged against a seat seal 84 by a coil spring 86, thereby closing a
respective outlet port. Needle 80 can be withdrawn from seat 84,
against the normal bias of spring 86, by pulling on an actuation
line (not shown), manually or otherwise, that connects to a
proximal end of the needle, thereby opening the port. In another
embodiment, a pressure-actuated valving mechanism is employed.
Here, the valve is adapted to open automatically upon reaching a
certain, predetermined threshold pressure at the port.
[0052] As previously indicated, one advantage provided by the
present invention is the avoidance of tissue damage often
associated with the use of needles. Nevertheless, it should be
noted that in certain circumstances a limited amount of tissue
damage at or about the injection site may be desirable. For
example, where angiogenic agents are being delivered, tissue injury
can be beneficial in creating an environment where the action of
such agents is enhanced. Thus, it will sometimes be desired to
configure the outlet ports to produce jet or spray patterns
appropriate for effecting a desired amount of tissue damage over a
selected area.
[0053] In addition to the lumen arrangements described above with
respect to FIGS. 2-4, the present invention further contemplates an
assembly including one or more elongate tubular elements that can
be removably received within a primary lumen defined by an outer
elongate sleeve. Each removable tubular element, in this
embodiment, defines a sub-lumen or delivery lumen through which one
or more selected agents can pass, and includes a distal-end face
defining one or more respective outlet ports. Preferably, each
tubular element is adapted to slide longitudinally through the
primary lumen of the elongate sleeve for placement therein and
removal therefrom, as desired. One embodiment, for example,
provides such a tubular element coaxially within an elongate
sleeve. The sleeve or the tubular element can incorporate pull-wire
steering and/or fixed shapes at their distal end to facilitate
navigation. Another embodiment provides such a tubular element
extending side-by-side with a guidewire lumen from a proximal to a
distal end of an elongate sleeve. In still a further embodiment,
such a tubular element is incorporated in a rapid-exchange
external-guidewire apparatus. In an exemplary construction of the
latter, the tubular element extends longitudinally from a proximal
to a distal end of the elongate sleeve, and runs side-by-side with
a guidewire lumen along a distal region (e.g., about 3-5 mm) of the
sleeve. For example, the present invention can be incorporated in a
rapid-exchange apparatus substantially as taught in U.S. Pat. No.
5,061,273; which is incorporated entirely herein by reference. In
yet a further embodiment, such a tubular element is adapted to be
removed from a lumen extending longitudinally through the sleeve
and replaced with a guidewire for facilitating catheter advancement
across an anatomical structure such as a heart valve.
[0054] In a further exemplary arrangement, a guidewire lumen is
coaxial with one or more delivery lumens, with the guidewire lumen
at the center and the delivery lumens surrounding the guidewire
lumen. It is contemplated that the guidewire lumen can be used to
place other elongated devices, if desired, such as ultrasound
sensors to measure wall thickness or pressure sensors to infer
contact against a wall.
[0055] An agent reservoir can be utilized for holding a selected
therapeutic and/or diagnostic agent until delivery. The reservoir
can be of any suitable type. In one exemplary construction, the
reservoir is configured to hold a fluidic agent (e.g., in liquid
form) for introduction, using a substantially closed system, into
an agent-delivery lumen of the jacket. For example, the agent can
be held within a chamber provided inside the catheter jacket, or it
can be introduced from an external reservoir, such as a syringe or
bag, via a conventional introduction port located along the hand
unit or along a proximal region of the jacket. In one embodiment,
the hand unit is provided with a fixed internal reservoir for
holding a supply of a selected agent to be dispensed. In this
embodiment, a supply reservoir, such as a syringe, can communicate
with the internal reservoir via a connector provided in the hand
unit's outer housing. The connector is preferably a substantially
sterile connector, such as a standard Luer-type fitting or other
known standard or proprietary connector. In another embodiment, the
supply reservoir comprises a syringe, pre-loaded with a selected
agent, that can be removably fit into a holding area inside the
housing of the hand unit, as taught, for example, in co-pending
U.S. patent application Ser. No. 09/080,175, filed May 16, 1998,
entitled, "Drug Delivery Module," to Glines et al.; incorporated
entirely herein by reference.
[0056] A pressure-control source is provided in fluid communication
with one or more of the agent-delivery lumens. The pressure-control
source, e.g., a manual or automatic pump, is operable to establish
an elevated pressure within such lumen(s) such that an agent placed
therein will be propelled toward, and out of, one or more of the
outlet ports, thereby forming one or more respective fluid jets or
streams capable of penetrating a selected tissue disposed adjacent
thereto. In one embodiment, the pressure-control source is a
hand-operable syringe-type pump, connected to one or more lumens
along a proximal end of the jacket. Commercially available
pressure-control sources that can be readily adapted for use herein
include, for example, power injectors, such as the ACIST Injection
System Model CL 100 (ACIST Medical Systems), and inflation devices,
such as the ARIA or BREEZE inflation devices from Schneider/Namic
(Glen Falls, N.Y.).
[0057] An exemplary method of using the above catheter assembly
will now be described, wherein the catheter assembly is used for
intra-myocardial delivery of a selected therapeutic and/or
diagnostic agent. Initially, catheter shaft 16 is percutaneously
introduced via femoral or radial artery access. Once arterial
access is established, the catheter shaft is slid across the aortic
valve and into the left ventricle chamber. The distal end of the
catheter shaft is maneuvered so as to be substantially
perpendicular to the endocardial wall 28 (FIG. 2B), using
fluoroscopic visualization and/or ultrasound guidance, and pressed
into contact therewith. A selected agent, in fluidic form, is then
introduced into a proximal-end region of lumen 22, and the lumen is
pressurized so as to achieve about 200-300 psi along the proximal
end with a drop to about 20-100 psi (preferably about 20-30 psi)
along the distal end. Under the influence of such pressure, the
agent is propelled through the lumen, to and out of one or more
outlet ports. In this way, one or more narrow jets or streams are
directed at the endocardial wall. Each jet penetrates the tissue to
a depth of between about 2-10 mm, and preferably about 5 mm. The
injection is carried out over a time period of about 1-15
seconds.
[0058] Instead of a catheter-type device, the invention can be
incorporated in other percutaneous and/or surgical devices. For
example, one embodiment contemplates an endoscope-type device
having an elongate shaft with one or more longitudinally extending
lumens extending therethrough. As with the catheter-type device,
the structure defining each lumen (e.g., the endoscope shaft, or
one or more tubes extending through the shaft) is configured to
withstand an elevated pressure (e.g., up to 300 psi) in the lumen.
Also, like the catheter-type device, a substantially blunt,
distal-end face defines one or more outlet ports communicating with
one or more of the lumens; with each of the outlet ports having a
diameter of about 0.025", or less (e.g., 0.006"). A
pressure-control source, such as a pump, is provided in fluid
communication with one or more of the lumens, operable to establish
an elevated pressure within such lumen(s) such that an agent placed
therein will be propelled toward, and out of, one or more of the
outlet ports, thereby forming one or more respective fluid jets or
streams capable of penetrating a selected tissue disposed adjacent
thereto. Various other details pertaining to agent delivery are
substantially like those set forth herein with regard to the
catheter-type device.
[0059] In an exemplary use, the endoscope-type device of the
invention is introduced thoracoscopically or through a thoracotomy,
to direct high-energy jets at the wall or surface of a selected
tissue or organ. For example, one or more high-energy jets can be
directed at the epicardial surface of the heart, permitting one or
more selected agents to penetrate the myocardial tissue. The
surgical device can incorporate a thoracoscopic camera (e.g., a
reusable 5 mm camera) axially mounted to provide an operator with a
suitable field of view through a lens. This allows the operator to
work through a common Trocar access port placed, for example,
through a patient's chest wall.
[0060] It is noted that the above-described methods are merely
exemplary in nature. Those skilled in the art will appreciate that
the present invention provides for the delivery of selected agents
to a wide variety of body organs and regions.
[0061] In another embodiment of the present invention, a selected
therapeutic and/or diagnostic agent is held within a reservoir at
the distal-end region of an elongate shaft and delivered into a
tissue by means of ultrasonic energy. Pertinent portions of an
exemplary agent-delivery apparatus, which can be incorporated in a
catheter-type device or an endoscope-type, such as previously
described, are shown in FIG. 5. Here, the distal-end region of a
catheter-type device is shown, having an ultrasonic transducer 52
(e.g., a piezoelectric transducer, such as barium titanate, lead
zirconate titanate, or the like) disposed across lumen 22. The
distal end of the catheter jacket defines a single, relatively
large opening, denoted as 56; however, a cap or plug with one or
more smaller openings (similar to that as described above) can be
used instead. The transducer is operable to emit ultrasonic energy,
of appropriate intensity (e.g., up to about 6 watts/cm2) and
frequency (e.g., up to about 20 MHz), along a generally axial
direction toward a wall or surface region of a selected organ or
tissue 28 within a subject body. The energy, so applied, is
effective to cause an agent 58, held within a holding region near
the distal end of the catheter jacket, to move toward and penetrate
the tissue wall. In one embodiment, the agent is distributed in a
polymer matrix, or other solid or semi-solid form, within the
holding region. The agent is maintained in the matrix within the
holding region until the time of delivery. Alternatively, the agent
(e.g., in liquid or semi-solid form) can be maintained within the
holding region until delivery by providing a semi-permeable
membrane between the agent and the opening at the distal end of the
catheter jacket. Other means for maintaining the agent in the
holding region until delivery will be apparent to those skilled, in
the art.
[0062] In another embodiment, a selected therapeutic and/or
diagnostic agent is held within a distal-end region of a catheter
or endoscope-type device and propelled into a target tissue or
organ using a biolistic particle-delivery or bombardment assembly.
In one embodiment, the biolistic assembly (e.g., a so-called "gene
gun" incorporated along a distal-end region of the agent-delivery
device) introduces nucleic acid-coated microparticles, such as
DNA-coated metals, into a tissue at high energies. The coated
particles can be propelled into the tissue using any suitable
means, e.g., an explosive burst of an inert gas e.g., (helium), a
mechanical impulse, a centripetal force, and/or an electrostatic
force (See, e.g., U.S. Pat. No. 5,100,792 to Sanford et al.;
incorporated entirely herein by reference). In an exemplary
embodiment, a spark discharge between electrodes placed near the
distal-end region of the catheter, proximal of a distal-end
agent-holding region, is employed to vaporize a water droplet
deposited therebetween, which then creates a shock wave capable of
propelling the DNA-coated particles. The technique allows for the
direct, intracellular delivery of DNA. The carrier particles are
selected based on their availability in defined particle sizes
(e.g., between about 10 and a few micrometers), as well as having a
sufficiently high density to achieve the momentum required for
cellular penetration. Additionally, the particles used are
preferably chemically inert to reduce the likelihood of explosive
oxidation of fine microprojectile powders, as well as non-reactive
with DNA and other components of the precipitating mixes, and
display low toxicity to target cells (See e.g., Particle
Bombardment Technology for Gene Transfer, (1994) Yang, N. ed.,
Oxford University Press, New York, N.Y. pages 10-11; incorporated
entirely herein by reference). For example, tungsten and/or gold
particle microprojectiles can be employed to achieve adequate gene
transfer frequency by such direct injection techniques.
Alternatively, or in addition, diamond particles, as well as glass,
polystyrene and/or latex beads can be used to carry the DNA. The
DNA-coated particles can be maintained in the agent-holding region
by any suitable means, e.g., precipitated on the distal face of a
carrier sheet suspended across a lumen at or near the distal end of
the jacket. In this latter embodiment, the propulsion means propels
the DNA-coated particles from a distal face of the carrier sheet
into a selected target tissue or organ adjacent thereto.
[0063] It will be appreciated that, especially with regard to
catheter-type delivery apparatuses, an agent directed from a distal
end of the apparatus with sufficiently high energy may cause such
end to move away from a target tissue wall or surface. FIG. 8, for
example, shows a portion of a steerable catheter 92 having a distal
end positioned adjacent a target region of an endocardial wall 28
of a patient's left ventricle 94. Arrows "A" and "B" depict an
"action-reaction" phenomenon, with (i) arrow "A" representing an
injection force provided by one or more high-energy fluid jets or
streams directed against the wall 28, with the jet(s) carrying, for
example, an angiogenic agent (e.g., "naked" DNA), and (ii) arrow
"B" representing a resultant, oppositely-directed force tending to
push the distal tip of the catheter away from the endocardial wall.
To counter the latter, means are provided for maintaining the
distal end of the catheter proximate the endocardial wall. In the
illustrated embodiment, a secondary lumen 96 extends longitudinally
along the catheter and terminates at a distal orifice 98, short of
the catheter's distal end (e.g., by between about 1-4 cm). An
elongate wire 102 is slidably received within the secondary lumen
96 and has its distal end attached to the catheter at, or near, the
catheter's distal end. From a remote (proximal) location, wire 102
can be moved between a retracted position, with the distal region
of the wire positioned closely adjacent the catheter (not shown),
and an extended position, with a distal region of the wire extended
beyond the secondary lumen's distal orifice so as to bow away from
the catheter shaft (shown in FIG. 8). At such extended position, a
central region of the bowed portion of the wire presses against a
back wall of the ventricle, as at arrows "E," thereby causing a
distal region of the bowed portion to urge the catheter's distal
end toward the target region of the endocardial wall, as indicated
by arrow "C." In another embodiment, a region of the catheter,
toward its distal end, is configured with a pre-formed (normal)
bend of sufficient stiffness or rigidity to maintain the distal tip
of the shaft proximate the target region of the endocardial wall,
notwithstanding such "action-reaction" forces. For example, a
reinforced external sleeve can be placed over the region "D" of the
catheter shaft to impart the desired bend along such region.
Alternatively, the bend along region "D" can be inducible from a
remote position.
[0064] In general, the apparatus and method of the present
invention may employ a wide variety of agents, e.g., ranging from
active compounds to markers to gene therapy compounds. Exemplary
agents, contemplated for use herein, are set forth in U.S. Pat.
Nos. 5,840,059; 5,861,397; 5,846,946; 5,703,055; 5,693,622;
5,589,466; and 5,580,859, each incorporated entirely herein by
reference. In one embodiment, for example, the invention is
employed to deliver ore or more genes (e.g., as so-called "naked
DNA") into cavities formed into the myocardium of a subject.
[0065] In one embodiment, wherein the agent includes DNA,
controlled-release preparations are formulated through the use of
polymers to complex or absorb the selected gene sequence (with or
without an associated carrier, e.g., liposomes, etc.). The agents
can be formulated according to known methods to prepare
pharmaceutically useful compositions, whereby these materials, or
their functional derivatives, are combined in admixture with a
pharmaceutically acceptable carrier vehicle. Suitable vehicles and
their formulation, are described, for example, in Nicolau, C. et
al. (Crit. Rev. Ther. Drug Carrier Syst. 6:239-271 (1989)), which
is incorporated entirely herein by reference. In order to form a
pharmaceutically acceptable composition suitable for effective
administration, such compositions will contain an effective amount
of the desired gene sequence together with a suitable amount of
carrier vehicle.
[0066] Additional pharmaceutical methods may be employed to control
the duration of action. Controlled delivery may be exercised by
selecting appropriate macromolecules (for example polyesters,
polyamino acids, polyvinyl, pyrrolidone, ethylenevinylacetate,
methylcellulose, carboxymethylcellulose, or protamine, sulfate) and
the concentration of macromolecules as well as the methods of
incorporation in order to control release. Another method to
control the duration of action by controlled release preparations
is to incorporate the agent into particles of a polymeric material
such as polyesters, polyamino acids, hydrogels, poly(lactic acid)
or ethylene vinylacetate copolymers. Alternatively, instead of
incorporating these agents into polymeric particles, it is possible
to entrap these materials in microcapsules prepared, for example,
by coacervation techniques or by interfacial polymerization, for
example, hydroxymethylcellulose or gelatin microcapsules and
poly(methylmethacylate) microcapsules, respectively, or in
colloidal drug delivery systems, for example, liposomes, albumin
microspheres, microemulsions, nanoparticles, and nanocapsules or in
macroemulsions.
[0067] In a typical use, the agent will enter at one or more target
regions along a surface or wall of a selected tissue, and diffuse
into the tissue, aided by the action of the jets. Advantageously,
the high-energy jets provided herein can be utilized even when the
distal end of the apparatus (e.g., a catheter shaft) is highly
deflected.
[0068] It should now be appreciated that the present invention
provides a number of advantages over the prior needle-based
injection systems. For example, a greater area/volume of tissue can
be treated with each delivery as compared to conventional
single-needle systems. Also, the present invention is greatly
simplified over most of the known needle-based delivery systems.
For example, the high-energy jet delivery arrangements herein do
not require a reciprocally movable shaft, as required by the known
needle-based delivery systems for advancing the needle into a
tissue from a remote location, which can limit the useful range of
action.
[0069] Those skilled in the art can now appreciate from the
foregoing description that the broad teachings of the present
invention can be implemented in a variety of forms. Therefore,
while this invention has been described in connection with
particular embodiments and examples thereof, the true scope of the
invention should not be so limited. Various changes and
modification may be made without departing from the scope of the
invention, as defined by the appended claims.
* * * * *