U.S. patent application number 13/367965 was filed with the patent office on 2013-06-13 for antibiotic-bound poly(caprolactone) polymer.
This patent application is currently assigned to UNIVERSITY OF SOUTH FLORIDA. The applicant listed for this patent is Michelle Leslie, Edward Turos. Invention is credited to Michelle Leslie, Edward Turos.
Application Number | 20130150550 13/367965 |
Document ID | / |
Family ID | 38685905 |
Filed Date | 2013-06-13 |
United States Patent
Application |
20130150550 |
Kind Code |
A1 |
Turos; Edward ; et
al. |
June 13, 2013 |
Antibiotic-Bound Poly(Caprolactone) Polymer
Abstract
This invention is the design and synthesis of a caprolactone
monomer which bears a pendant protected carboxyl group. This
monomer has been copolymerized with caprolactone in varying ratios.
After polymerization, the protecting group can be removed and an
antibiotic can be attached as a new pendant group. The bioactivity
of the antibiotic-bound poly(caprolactone) polymer is
described.
Inventors: |
Turos; Edward; (Wesley
Chapel, FL) ; Leslie; Michelle; (Tampa, FL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Turos; Edward
Leslie; Michelle |
Wesley Chapel
Tampa |
FL
FL |
US
US |
|
|
Assignee: |
UNIVERSITY OF SOUTH FLORIDA
Tampa
FL
|
Family ID: |
38685905 |
Appl. No.: |
13/367965 |
Filed: |
February 7, 2012 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11746704 |
May 10, 2007 |
8110678 |
|
|
13367965 |
|
|
|
|
60747061 |
May 11, 2006 |
|
|
|
Current U.S.
Class: |
528/310 ;
528/354 |
Current CPC
Class: |
C07D 313/04 20130101;
A61K 31/21 20130101; C07D 405/12 20130101; Y02P 20/55 20151101 |
Class at
Publication: |
528/310 ;
528/354 |
International
Class: |
A61K 31/21 20060101
A61K031/21 |
Goverment Interests
STATEMENT OF GOVERNMENT INTEREST
[0002] This invention was made with Government support under Grant
No. RO1 A1 51351 awarded by the National Institutes of Health. The
Government has certain rights in the invention.
Claims
1. A homopolymer derived from polymerization of a single compound
represented by the formula below: ##STR00013## wherein R1 is alkyl,
R2 is an aryl, R3 is alkyl or aryl.
2. A homopolymer derived from polymerization of a single compound
represented by the formula below: ##STR00014## wherein R1 is alkyl,
R2 is an aryl.
3. A homopolymer derived from polymerization of a single compound
represented by the formula below: ##STR00015##
4. A homopolymer derived from polymerization of a single compound
represented by the formula below: ##STR00016##
5. A copolymer derived from polymerization of a plurality of
compounds represented by the formulas below: ##STR00017## wherein
R1 is alkyl, R2 is an aryl, R3 is alkyl or aryl.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This divisional application claims priority to U.S.
Non-Provisional Application Ser. No. 11/746,706 filed on May 10,
2007 and U.S. Provisional Application No. 60/747,061 filed on May
11, 2006, entitled "Antibiotic-Bound Poly(Caprolactone)
Polymer".
FIELD OF INVENTION
[0003] This invention relates to attaching one or more bioactive
molecules to the same polymer, and also for attachment before or
after polymerization
BACKGROUND OF THE INVENTION
[0004] The delivery of water-insoluble drugs to targets within the
human body is a challenge that presently places strict limitations
on what drugs can be applied clinically. The need for methods which
overcome this is of high priority in the development of new
therapeutics for treatment of human disease.
[0005] The development of antibiotics for control of pathogenic
bacteria has been of pressing need in this era of drug resistant
infections. N-Methylthiolated b-lactams have been identified as a
new family of antibacterial agents active against Staphylococcus
bacteria, including methicillin-resistant Staphylococcus aureus
(MRSA). (See Turos, E.; Konaklieva, M. I.; Ren, R. X. F.; Shi, H.;
Gonzalez, J.; Dickey, S.; Lim, D. Tetrahedron 2000, 56, 5571; Bart
Heldreth, Timothy E. Long, Seyoung Jang, Suresh K. R.
Guntireddygari, Edward Turos, Sonja Dickey, Daniel V. Lim,
"N-Thiolated b-Lactam Antibacterials: Effects of the N-Organothio
Substituent on anti-MRSA Activity," Bioorganic and Medicinal
Chemistry 14, 3775-3784 (2006); and Edward Turos, Jeung-Yeop Shim,
Yang Wang, Kerriann Greenhalgh, G. Suresh Kumar Reddy, Sonja
Dickey, Daniel V. Lim, "Antibiotic-Conjugated Polyacrylate
Nanoparticles: New Opportunities for Development of Anti-MRSA
Agents," Bioorganic and Medicinal Chemistry Letters 16, in press
(2006); which are incorporated herein by reference).
[0006] The compounds have also displayed promising anticancer
properties. These lactams exert their growth inhibitory effects on
bacteria through a mode of action that is distinctively different
to that of other b-lactam antibiotics, and possess
structure-activity patterns unlike those already mapped for other
b-lactam antibacterials such as the penicillins. One of the major
limitations in the potential application of these N-thiolated
b-lactam compounds, however, is their exceedingly low water
solubility.
[0007] Drug delivery vehicles such as liposomes and gold
nanoparticles have been developed to improve bioavailability,
efficacy, and specificity of pharmaceutical compounds, particularly
for anticancer agents, but nanoparticles have received surprisingly
little attention in the antibiotic and infectious disease area.
Some of the few notable examples have included
antibiotic-encapsulated polymeric nanoparticles and liposomes,
biodegradable nanospheres and surface-coated gold and silver
nanoparticles.
SUMMARY OF INVENTION
[0008] In one embodiment, the invention provides an effective drug
delivery platform that would enhance the water solubility of the
lactams, without sacrificing inherent bioactivity.
[0009] In another embodiment, the invention provides for the
development of antibacterial polyacrylate nanoparticles based on
well-precedented emulsion polymerization procedures.
[0010] This invention addresses this need, and demonstrates the use
of antibiotic-bound poly (caprolactone) polymers as anti-infective
materials for biomedical applications in the prevention of
bacterial infections.
[0011] In a first embodiment, the invention includes a
functionalized compound comprising at least one caprolactone ring
with an appended functional group. A plurality of methylene groups
act as a spacer between the lactone ring and the functional group.
In a preferred embodiment, the functional group is an antibiotic,
such as a N-thiolated .beta.-lactam. The functional group is
preferably covalently bonded.
[0012] In an alternate embodiment, a method is provided for
producing the functionalized compound of the previous embodiment.
The method includes providing a at least one caprolactone ring with
a protecting group spaced apart from the caprolactone ring by a
plurality of methylene groups. The protecting group is then cleaved
from the caprolactone ring and replaced by bonding a functional
group to the caprolactone ring. Illustrative reagents for cleaving
the protecting group include 10% pd/C as a catalyst in the presence
of H.sub.2(g) and ethyl acetate (EtOAc). The protecting group is
selected from the group consisting of alcohol protecting groups,
amine protecting groups, carbonyl protecting groups and carboxyl
protecting groups. In a preferred embodiment, the protecting group
is selected for the group consisting of a benzel ester and a
tert-butyl ester. As with the previous embodiment, the functional
group is an antibiotic such as a N-thiolated .beta.-lactam.
[0013] In another embodiment, the invention includes the compound
represented by the formula:
##STR00001##
[0014] or a pharmaceutically acceptable salt or ester thereof,
wherein is selected from the group consisting of water-insoluble
drugs, antibiotics, lactams, .beta.-lactams, N-thiolated
.beta.-lactams and protecting groups. The protecting group is
selected from the group consisting of alcohol protecting groups,
amine protecting groups, carbonyl protecting groups and carboxyl
protecting groups.
[0015] In yet another embodiment, the invention includes the
compound represented by the formula:
##STR00002##
[0016] or a pharmaceutically acceptable salt or ester thereof.
[0017] In another embodiment, the invention includes the compound
represented by the formula:
##STR00003##
[0018] or a pharmaceutically acceptable salt or ester thereof.
[0019] In still another embodiment, the invention includes the
compound represented by the formula:
##STR00004##
[0020] or a pharmaceutically acceptable salt or ester thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] For a fuller understanding of the nature and objects of the
invention, reference should be made to the following detailed
description, taken in connection with the accompanying drawings, in
which:
[0022] FIG. 1 shows the polymerization of a caprolactone monomer to
polycaprolactone (PCL).
[0023] FIG. 2 shows the functionalized caprolactone polymer can be
used for covalent binding of drug molecules.
[0024] FIG. 3 shows examples of functionalized caprolactones from
the literature.
[0025] FIG. 4 shows the functionalized lactone of present
invention.
[0026] FIG. 5A shows drug appendage before polymerization.
[0027] FIG. 5B shows drug appendage after polymerization.
[0028] FIG. 6 shows lactone resynthesis.
[0029] FIG. 7 shows ylide synthesis.
[0030] FIG. 8 is an image showing results of biological testing of
the lactam-containing monomer vs. MSSA.
[0031] FIG. 9 demonstrates the anti-Bacillus activity of the
.beta.-lactam containing copolymer.
[0032] FIG. 10 shows the invention employing an alternate carboxyl
protecting group.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0033] In the following detailed description of the preferred
embodiments, reference is made to the accompanying drawings, which
form a part hereof, and within which are shown by way of
illustration specific embodiments by which the invention may be
practiced. It is to be understood that other embodiments may be
utilized and structural changes may be made without departing from
the scope of the invention.
[0034] N-Thiolated .beta.-Lactams
[0035] New family of anti-MRSA and anti-Bacillus agents that have
recently been reported by our laboratory. Extensive SAR studies
have shown that changing the N-thioalkyl substituent has a large
effect on the bioactivity and that changes at the other positions
of the ring exert a more subtle effect. Recent research in our
group has been focused on covalent attachment of these and other
antibiotics to polymers for drug, delivery and for new
biomaterials.
##STR00005##
[0036] As used herein, the term "drug" to any therapeutic or
prophylactic agent other than food which is used in the prevention,
diagnosis, alleviation, treatment, or cure of disease in man or
animal.
[0037] As used herein, the term "antibiotic" refers to any natural,
synthetic, and semi-synthetic compound that has been identified as
possessing antibacterial, antifungal, antiviral, or antiparasitic
activity.
[0038] Polycaprolactones
[0039] Polycaprolactone (PCL) is a biodegradable polyester which
can be prepared by ring opening polymerization of
.epsilon.-caprolactone using a catalyst such as stannous octanoate,
as shown in FIG. 1. PCL is degraded by hydrolysis of its ester
linkages in physiological conditions (such as in the human body)
and is therefore useful as a biomaterial. PCL has been approved by
the Food and Drug Administration (FDA) for use in the human body as
(for example) a suture (sold under the brand name Monocryl.TM. or
generically). In particular, PCL has been used in long term
implantable devices, owing to its degradation which is relatively
slow. (See V. R. Sinha, K. Bansal, R. Kaushik, R. Kumria and A.
Trehan; Poly-.epsilon.-caprolactone microspheres and nanospheres:
an overview, International Journal of Pharmaceutics, Volume 278,
Issue 1, 18 Jun. 2004, Pages 1-23; which is incorporated herein by
reference.)
[0040] The characteristics of PCL make it useful as a delivery
mechanism for antibiotics. For example PCL is biodegradable (bulk
hydrolysis of ester bonds), the byproducts of degradation are
non-toxic (biocompatible), it is FDA approved and displays high
permeability to many drugs. Therefore, the invention provides a
functionalized caprolactone polymer can be used for covalent
binding of drug molecules (FIG. 2).
[0041] The functionalized caprolactones of the prior art
(Detrembleur et al Macromolecules, 2000, 33, 14-18 and Trollsas et
at Macromolecules, 2000, 33, 4619-4627) are shown in FIG. 3. In
contrast, the functionalized lactone 10 of present invention is
shown in FIG. 4. Lacton 10 comprises at least one lactone ring 12,
functional group 16 and at least one spacer 14. As it can be seen,
functional group 16 is placed away from site of polymerization.
Moreover, an additional methylene spacer 14 between functional
group 16 and lactone ring 12 enhances further
functionalization.
[0042] In another embodiment, the invention provides a method of
producing an antibiotic-conjugated functionalized caprolactone
(FIG. 5A and FIG. 5B). In Step 1 includes providing a caprolactone
comprising lactone ring 12, methylene spacer 14 and protecting
group 18. In Step 2, protecting group 18 is cleaved, preferably
under mild conditions. Finally, in Step 3, drug of interest 20 is
covalently bonded to the finished compound. FIG. 5A illustrates the
method of appending a drug of interest to the functionalized
lactone before polymerization. FIG. 5B illustrates the method of
appending a drug of interest to the functionalized lactone after
polymerization. Lactone retrosynthesis is shown in FIG. 6 and Ylide
synthesis is shown in FIG. 7.
Example 1
[0043] The following represents an embodiment of the invention
wherein 1,4-dioxaspiro[4.5]decan-8-one is used to synthesize a
functionalized lactone bearing a pendent benzyl ester as the
protecting group.
##STR00006##
[0044] Reagents and conditions: (a) 2 eq. ylide, C.sub.6H.sub.6, 12
h, reflux; (b) 60 psi H.sub.2(g), cat. 10% Pd/C, MeOH, 12 h; (c)
3LiOH, MeOH, 12 h, rt; 1M HCl; (d) 3K.sub.2CO.sub.3, 1.1 BnBr,
MeCN, 12 h, reflux; (e) 70% AcOH, 12-24 h, rt; (f) 1.5mCPBA,
CHCl.sub.3, 3-5 h, reflux.
[0045] Next the functionalized lactone is coupled with an
antibiotic, here N-thiolated .beta.-lactam, after deprotection of
benzyl ester. FIG. 8 shows the results of biological testing of the
lactam-containing monomer vs. MSSA.
##STR00007##
[0046] Reagents and conditions: (a) cat. 10% Pd/C, 60 psi
H.sub.2(g), EtOAc, 12 h; (b) 1.5 eq. EDCl, cat. DMAP, dry
CH.sub.2Cl.sub.2, 12 h, rt.
Example 2
[0047] In another embodiment, the invention provides a PCL derived
from copolymerization of a functionalized lactone monomer with
caprolactone. Copolymers containing 10%, 15%, 20%, 25% and 30% of
the substituted lactone were prepared and characterized by TLC,
.sup.1H, NMR, .sup.13C NMR and MALDI-TOF. The Copolymers displayed
low molecular, between about 1000 and 4000.
##STR00008##
[0048] Deprotection of the copolymer and coupling with the
antibiotic, .beta.-lactam, is shown below and was achieved using
the following reagents and conditions: (a) cat. 10% Pd/C,
H.sub.2(g), EtOAc, 12-24 h. (b) 15 EDCI, cat. DMAP, dry
CH.sub.2Cl.sub.2, 12 h. rt. The antibiotic activity of the
completed PCL against Bacillus is shown in FIG. 9.
##STR00009##
Example 3
[0049] In yet another embodiment, the functionalized lactone
comprises a carboxyl protecting group, as shown in FIG. 10. Ylide
synthesis is shown below using the reagents and conditions: (a)
PPh.sub.3, C.sub.6H.sub.6, 12 h, rt; (b) 20% NaOH.sub.(aq), 5 h,
rt.
##STR00010##
Example 4
[0050] The following demonstrates the synthesis of lactone bearing
pendant tert-butyl ester using the reagents and conditions: (a) 1.5
eq. ylide C.sub.6H.sub.6. 12 h, reflux, (b) H.sub.2(g), cat. 10%
Pd/C, EtOAC, 24 h; (c) 0.1 eq. I.sub.2, dry acetone, 1 hr, rt; (d)
1.5mCPBA CHCl.sub.3, 3 h, reflux.
##STR00011##
[0051] Copolymerization with caprolactone was achieved as shown
below. Copolymers containing 10%, and 20% of the substituted
lactone were prepared and characterized by TLC, .sup.1H NMR and
.sup.13C NMR.
##STR00012##
[0052] Functional caprolactone monomers have been synthesized and
characterized. The monomers were further copolymerized with
caprolactone. Caprolactone monomers and polymers with covalently
bound N-thiolated .beta.-lactams have been prepared and shown to
possess bioactivity against MSSA and Bacillis respectively.
[0053] It will be seen that the advantages set forth above, and
those made apparent from the foregoing description, are efficiently
attained and since certain changes may be made in the above
construction without departing from the scope of the invention, it
is intended that all matters contained in the foregoing description
or shown in the accompanying drawings shall be interpreted as
illustrative and not in a limiting sense.
[0054] It is also to be understood that the following claims are
intended to cover all of the generic and specific features of the
invention herein described, and all statements of the scope of the
invention which, as a matter of language, might be said to fall
therebetween. Now that the invention has been described,
* * * * *