U.S. patent application number 11/786373 was filed with the patent office on 2008-01-03 for responsive microgel and methods related thereto.
This patent application is currently assigned to Supratek Pharma Inc.. Invention is credited to Lev E. Bromberg, Marina Temchenko.
Application Number | 20080003288 11/786373 |
Document ID | / |
Family ID | 27668634 |
Filed Date | 2008-01-03 |
United States Patent
Application |
20080003288 |
Kind Code |
A1 |
Bromberg; Lev E. ; et
al. |
January 3, 2008 |
Responsive microgel and methods related thereto
Abstract
A responsive microgel is provided which responds volumetrically
and reversibly to a change in one or more aqueous conditions
selected from the group consisting of (temperature, pH, and ionic
conditions) comprised of an ionizable network of covalently
cross-linked homopolymeric ionizable monomers wherein the ionizable
network is covalently attached to an amphiphilic copolymer to form
a plurality of `dangling chains` and wherein the `dangling chains`
of amphiphilic copolymer form immobile micelle-like aggregates in
aqueous solution. A responsive microgel is further provided that
comprises at least one therapeutic entity and delivers a
substantially linear and sustained release of the therapeutic
entity under physiological conditions.
Inventors: |
Bromberg; Lev E.;
(Swampscott, MA) ; Temchenko; Marina; (Swampscott,
MA) |
Correspondence
Address: |
MATHEWS, SHEPHERD, MCKAY, & BRUNEAU, P.A.
29 THANET ROAD, SUITE 201
PRINCETON
NJ
08540
US
|
Assignee: |
Supratek Pharma Inc.
Dorval
CA
|
Family ID: |
27668634 |
Appl. No.: |
11/786373 |
Filed: |
April 11, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10298808 |
Nov 18, 2002 |
7204997 |
|
|
11786373 |
Apr 11, 2007 |
|
|
|
60352200 |
Jan 29, 2002 |
|
|
|
Current U.S.
Class: |
424/486 ;
424/94.4; 424/94.5; 514/249; 514/27; 514/283; 514/411; 514/449;
514/47; 514/492; 514/50 |
Current CPC
Class: |
A61K 9/1641 20130101;
A61K 47/34 20130101; A61Q 19/00 20130101; A61K 8/042 20130101; A61K
8/90 20130101 |
Class at
Publication: |
424/486 ;
424/094.4; 424/094.5; 514/249; 514/027; 514/283; 514/411; 514/449;
514/047; 514/492; 514/050 |
International
Class: |
A61K 38/45 20060101
A61K038/45; A61K 31/282 20060101 A61K031/282; A61K 31/343 20060101
A61K031/343; A61K 31/40 20060101 A61K031/40; A61K 31/44 20060101
A61K031/44; A61K 31/452 20060101 A61K031/452; A61K 31/495 20060101
A61K031/495; A61K 9/16 20060101 A61K009/16; A61K 31/7028 20060101
A61K031/7028; A61K 31/7052 20060101 A61K031/7052; A61K 31/7072
20060101 A61K031/7072; A61K 31/7076 20060101 A61K031/7076; A61K
38/43 20060101 A61K038/43 |
Claims
1-3. (canceled)
4. A responsive microgel which comprises: an ionizable network of
covalently cross-linked homopolymeric ionizable monomers wherein
the ionizable network is covalently attached to an amphiphilic
copolymer to form a plurality of `dangling chains` and wherein the
`dangling chains` of amphiphilic copolymer form immobile aggregates
in aqueous solution; and at least one therapeutic entity.
5. A responsive microgel according to claim 4 which comprises a
cationic therapeutic entity.
6. A responsive microgel according to claim 4 which comprises a
hydrophobic therapeutic entity.
7. A responsive microgel according to claim 4 which comprises an
amphiphilic therapeutic entity.
8. A responsive microgel according to claim 4 which delivers a
substantially linear and sustained release of a hydrophobic or
amphiphilic therapeutic entity under physiological conditions.
9.-16. (canceled)
17. A method of administering at least one therapeutic entity to a
patient comprising administering a responsive microgel according to
claim 4.
18. A method of administering at least one therapeutic entity to a
patient according to claim 17 comprising orally administering a
responsive microgel.
19. A method of administering at least one therapeutic entity to a
patient according to claim 17 selected from the group consisting of
(hydrophobic entities, cationic entities, and amphiphilic
entities).
20. A method of administering at least one therapeutic entity to a
patient according to claim 17 selected from the group consisting of
(a steroidal antiandrogen, a non steroidal antiandrogen, an
estrogen, diethylstilbestrol, a conjugated estrogen, a selective
estrogen receptor modulator (SERM), a taxane, a LHRH analog,
substrates of ABC transporters such as P-glycoprotein; MRP1-MRP9;
ABC half-transporters such as BCRP and other transporters that are
involved into a limited drug transport across small intestinal
epythlium, cerebral endothelium and other barrier tissues in the
body, as well as substrates of metabolic enzyme isoforms without
limitation, cytochrome P-450; esterase; epoxide hydrolase; alcohol
dehydrogenase; aldehyde dehydroganase; dihydropyrimidine
dehydroganase; NADPH-quinone oxidoreductase; uridine 5'-triphosphat
glucoronosyltransferase; sulfotransferase; glutatione
S-transferase; N-acetiltransferase; histamine methyltransferase;
catechol-o-methyl transferase; thiopurine methyltransferase. This
group of therapeutic agents include without limitation doxorubicin
and other anthracyclines, mitoxantrone, mitomycin C, methotrexate,
paclitaxel, docetaxel and other taxanes, topotecan and other
camptotecines, cysplatin, carboplatin, oxaliplatin and other
platinum complexes; megesterol acetate and other steroids;
carvedilol and other beta-blocking agents; azidothymidine,
fludarabine and other nucleoside containing agents in their
dephospho, mono-, di- and tri-phosphorylated forms; vinblastine,
vincristine and other vinka alkaloids; etoposide and other
podophilotoxins).
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional of U.S. patent application
Ser. No. 10/298,808 filed Nov. 18, 2002 which claims the benefit of
U.S. Provisional Application Ser. No. 60/352,200 filed on Jan. 29,
2002 all of which are hereby incorporated in their entirety by
reference to this application.
FIELD OF THE INVENTION
[0002] The present invention relates to microgels comprised of an
ionizable network covalently attached to an amphiphilic copolymer,
which forms aggregates capable of solubilizing drugs in aqueous
solution. The responsive microgel reversibly responds
volumetrically to factors such as temperature, pH, and ionic
conditions. Particularly, the responsive microgel is able to imbibe
or solubilize a large amount of therapeutic agent and deliver a
substantially linear and sustained release of therapeutic agent
under physiological conditions.
BACKGROUND OF THE INVENTION
[0003] Volumetric changes (shrinking or swelling) of
temperature-sensitive microgel particles dispersed in water is an
intraparticle phenomenon, but it is known in the art that also
interparticle aggregation takes place during the collapse
transition. Very stable polymer dispersions have been synthesized,
for instance, using poly(ethylene oxide), PEO, as a stabilizing
agent. Ottewill, R. H., et al., Colloid Polym. Sci. 1995, 273,
379.
[0004] The most widely studied class of responsive polymers are
temperature responsive poly(alkylacrylamides), specifically
poly(N-isopropylacrylamide). Shibayama, M., et al., Advances in
Polymer Science; Springer-Verlag: Berlin, 1993; 109, pp 1-62;
Pelton, R. Adv. Colloid interface Sci. 2000, 85, 1-33. However,
poly(alkylacrylamides) are perceived to be toxic, especially in
biomedical applications. L. E. Bromberg and E. S. Ron, Adv. Drug
Delivery Revs., 1998, 31, 197-221. Furthermore, nonionic nature of
poly(alkylacrylamides) prevents creating ion-sensitive
microgels.
[0005] Synthesis of polymers comprised of polyethers such as
poly(ethylene oxide), poly(propylene oxide) and their copolymers
grafted onto poly(acrylic acid) and other polyelectrolytes such as
poly(2-acrylamido-2-methylpropanesulfonic acid), polyethyleneimine
and the like are known in the art. See, e.g., Hourdet, D., et al.,
Polymer (1994), 35(12), 2624-30; L'Alloret, et al., Colloid Polym.
Sci. (1995), 273(12), 1163-73; L'alloret, F.; Maroy, P., et al.,
Revue de l'institut Francais du Petrole (1997), 52(2), 117-128;
Hourdet, D. et al., Macromolecules; 1998; 31(16); 5323-5335;
Schiumberger, D. C., EPO Publication 0 583 814 A1, 1993; 0 629 649
A1, 1994; Hoffman, et al., Advanced Biomaterials in Biomedical
Engineering and Drug Delivery Systems, Ogata, N., et al., Kim, S.
W., Feijen, J., Okano, T., Eds., Springer: Tokyo, 1996; pp 62-66;
Hoffman, A. S., et al., Proc. Inte. Symp. Controlled Release
Bioact. Mater. (1995), 22, 159; Chen, G., et al., Proc. Int. Symp.
Controlled Release Bioact. Mater. (1995), 22, 167; Hoffman, A. S.;
E. S. Ron, L. E. Bromberg, M. Temchenko, End Modified Thermal
Responsive Microgels, U.S. Pat. No. 6,316,011.
[0006] These polymers are synthesized by conversion of one or both
terminal OH-groups of a polyether into a more active group such as
NH.sub.2--, SH--, followed by grafting of the resulting modified
polyether onto the backbone of a chosen polyelectrolyte. Structures
that could result from these syntheses may comprise, for example,
un-cross-linked PLURONIC.RTM. copolymer bonded to poly(acrylic
acid). See, e.g., A. S. Hoffman, et al., Advanced Biomaterials in
Biomedical Engineering and Drug Delivery Systems, N. Ogata, S. W.
Kim, J. Feijen, T. Okano, eds., Springer, Tokyo, 1996, pp. 62-66; A
S Hoffman, et al., Polym. Prepr., 38: 524-525, (1997); G. Chen, et
al., Poly(ethylene glycol) Chemistry and Biological Applications,
edited by J. Milton Harris, S. Zalipsky, eds., American Chemical
Society, Washington, D.C., (1997), ACS Symposium Series 680,
Chapter 27, pp. 441-457; A. S. Hoffman, et al., Frontiers in
Biomedical Polymer Applications, edited by R. M. Ottenbrite,
Technomic Publishing Co., Lancaster, Pa. 1999, Vol. 2, pp. 17-29;
A. S. Hoffman, et al., Block and graft copolymers and methods
related thereto, Int. Pat. Appl. WO 95/24430.
[0007] Alternatively, syntheses known in the art can result in
chemically cross-linked networks (gels, microgels, or nanogels) if
both termini of the polyether are chemically modified. See, e.g.,
U.S. Pat. No. 6,316,011; L. Bromberg, Crosslinked poly(ethylene
glycol) networks as reservoirs for protein delivery, J. Appl.
Polym. Sci., 59(1996)459-466; L. Bromberg, Temperature-sensitive
star-branched poly(ethylene oxide)-b-poly(propylene
oxide)-b-poly(ethylene oxide) networks, Polymer, 39(23)(1998)
5663-5669; Law, T. K., et al., Int. J. Pharm., 1984, 21, 277; Ping,
Q.; Law, T. K., et al., Int. J. Pharm., 1990, 61, 79.
[0008] However, chemical moieties (amide or other) required to
accomplish linkage between an amphiphilic copolymer such as
polyether and the polyelectrolyte (i.e. a chemical group absent in
parent polyether and polyelectrolyte) are generally toxic and
unacceptable for use in pharmaceutical and other applications.
Copolymers that comprise chemically unmodified amphiphilic
copolymer and polyelectrolyte bonded only through carbon-carbon
bond, where such toxicity issues are avoided, are known in the art.
See, e.g., L Bromberg, et al., Responsive polymer networks and
methods of their use, U.S. Pat. No. 5,939,485; E. S. Ron, et al.,
Compositions for pharmaceutical applications, Int. Patent Appl. WO
98/06438; E. S. Ron, et al., T. H. E. Mendum, Compositions for
cosmetic applications, Int. Patent Appl. WO 98/50005; L Bromberg,
Hydrophobically modified polyelectrolytes and polyelectrolyte
block-copolymers, Handbook of Surfaces and Interfaces of Materials,
H. S. Nalwa, ed., Academic Press, 2001, Vol. 4, Chapter 7; L
Bromberg, Biomedical applications of hydrophobically modified
polyelectrolytes and polyelectrolyte block-copolymers, S. Tripathy,
J. Kumar, H. S. Nalwa, eds. Handbook of Polyelectrolytes and Their
Applications. American Scientific Publishers, Stevenson Ranch,
Calif., 2002, Vol. 1, Chapter 51; L. E. Bromberg, T. H. E. Mendum,
M. Orkisz, E. S. Ron, E. C. Lupton, Applications of
poly(oxyethylene-b-oxypropylene-b-oxyethylene)-g-poly(acrylic acid)
polymers (Smart Responsive microgel.TM.) in drug delivery, Proc.
Polym. Mater. Sci. Eng., 76: 273-275, 1997; M. J. Orkisz, et al.,
Rheological properties of reverse thermogelling poly(acrylic
acid)-g-poly(oxyethylene-b-oxypropylene-b-oxyethylene) polymers
(Smart Responsive microgel.TM.), Proc. Polym. Mater. Sci. Eng., 76:
276-277, 1997; L. Bromberg, et al., Interpenetrating networks of
Poloxamer copolymers and poly(acrylic acid) as vehicles in
controlled drug delivery, J. Control. Release, 48 (2, 3): 305-308,
1997; L. E. Bromberg, T. H. E. Mendum, M. J. Orkisz, E. C. Lupton,
E. S. Ron,
Polyoxyethylene-b-polyoxypropylene-b-polyoxyethylene-g-poly(acrylic
acid) polymers (Smart Responsive microgel.TM.) as a carrier in
controlled delivery of proteins and peptides, Polym. Prepr., 38(2):
602-603, 1997; L. E. Bromberg, et al., Bioadhesive properties of
polyoxyethylene-b-polyoxypropylene-b-polyoxyethylene-g-poly(acrylic
acid) polymers (Smart Responsive microgel.TM.), Polym. Prepr.,
38(2): 626-627, 1997; L. Bromberg, A novel family of thermogelling
materials via C--C bonding between poly(acrylic acid) and
poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene
oxide), J. Phys. Chem. B, 102: 1956-1963, 1998; L. E. Bromberg, E.
S. Ron, Protein and peptide release from temperature-responsive
gels and thermogelling polymer matrices, Adv. Drug Delivery Revs.,
31:197-221, 1998; L. E. Bromberg, M. G. Goldfeld, Self-assembly in
aqueous solutions of hydrophobically modified poly(acrylic acid),
Polym. Prepr., 39(2):681-682, 1998; L. Bromberg, Scaling of
rheological properties of responsive microgels from associating
polymers, Macromolecules, 31: 6148-6156, 1998; L. Bromberg,
Self-assembly in aqueous solutions of polyether-modified
poly(acrylic acid), Langmuir, 14: 5806-5812, 1998; L. Bromberg,
Polyether-modified poly(acrylic acid): synthesis and properties,
Ind. Eng. Chem. Res., 37: 4267-4274, 1998; L. Bromberg, Properties
of aqueous solutions and gels of poly(ethylene
oxide)-b-poly(propylene oxide)-b-poly(ethylene
oxide)-g-poly(acrylic acid), J. Phys. Chem B, 102: 10736-10744,
1998; L. Bromberg, L. Salvati, Bioactive surfaces via
immobilization of self-assembling polymers onto hydrophobic
materials, Bioconjugate Chem., 10: 678-686, 1999; L. E. Bromberg,
Interactions between hydrophobically modified polyelectrolytes and
mucin, Polym. Prepr., 40(2): 616-617, 1999; L. E. Bromberg, D. P.
Barr, Aggregation phenomena in aqueous solutions of hydrophobically
modified polyelectrolytes. Macromolecules, 32: 3649-3657, 1999; P.
D. T. Huibers, et al., Reversible gelation in semidilute aqueous
solutions of associative polymers: a small-angle neutron scattering
study, Macromolecules, 32: 4889-4894, 1999; L. Bromberg, E. Magner,
Release of hydrophobic compounds from micellar solutions of
hydrophobically modified polyelectrolytes, Langmuir, 15: 6792-6798,
1999; L. Bromberg, M. Temchenko, Loading of hydrophobic compounds
into micellar solutions of hydrophobically modified
polyelectrolytes, Langmuir, 15: 8627-8632, 1999; L. E. Bromberg, M.
Temchenko, R. H. Colby, Interactions among hydrophobically modified
polyelectrolytes and surfactants of the same charge, Langmuir, 16:
2609-2614, 2000; N. Plucktaveesak, et al., Effect of surfactants on
gelation threshold temperature in aqueous solutions of
hydrophobically modified polyelectrolyte, Proc. XIIIth
International Congress on Rheology, Cambridge, UK, 2000, Vol. 3,
pp. 307-309; L. Bromberg, Enhanced nasal retention of
hydrophobically modified polyelectrolytes, J. Pharm. Pharmacol.,
53: 109-114, 2001; L. Bromberg, Interactions among proteins and
hydrophobically modified polyelectrolytes, J. Pharm. Pharmacol.,
53: 541-547, 2001; A. K. Ho, L. E. Bromberg, et al., Solute
diffusion in solutions of associative polymers, Langmuir, 17:
3538-3544, 2001; R. H. Colby, et al., Critical incorporation
concentration of surfactants added to micellar solutions of
hydrophobically modified polyelectrolytes of the same charge,
Langmuir, 17: 2937-2941, 2001; L. Bromberg, Synthesis and
self-assembly of poly(ethylene oxide)-b-poly(propylene
oxide)-b-poly(ethylene oxide)-g-poly(acrylic acid) gels, Ind. Eng.
Chem. Res., 40: 2437-2444, 2001; L. Olivieri, et al., Study of the
breakup under shear of a new thermally reversible W/O/W multiple
emulsion, Pharm. Res., 18: 689-693, 2001; A. K. Ho, et al.,
Hydrophobic domains in thermogelling solutions of
polyether-modified poly(acrylic acid), Langmuir, 18: 3005-3013,
2002.
[0009] One-step methods of copolymer synthesis are known in the
art, e.g., L. Bromberg, J. Phys. Chem. B, 1998, 102, 1956-1963; L.
Bromberg, Ind. Eng. Chem. Res., 1998, 37, 4267-4274; P. D. T.
Huibers, et al., Macromolecules, 1999, 32, 4889-4894. However,
these prior art graft-comb copolymers are not permanently
cross-linked and therefore cannot respond volumetrically to changes
in their environment.
[0010] Previous Work
[0011] A variety of formulation approaches have been developed
aiming at the enhancement of the drug residence time and to
lowering the release rate, while maintaining the mucoadhesive
properties of the polyelectrolyte. See, e.g., K. J. Himmelstein, et
al., U.S. Pat. No. 5,599,534; T X Viegas, et al., U.S. Pat. No.
5,292,516; R Joshi, et al., Pharm Dev Technol. 4: 515-522 (1999);
Joshi, et al., U.S. Pat. No. 5,252,318. Typically, a
polyelectrolyte is mixed with more hydrophobic polymer to result in
a blend with enhanced drug-polymer interactions and higher
viscosity. It is preferred, however, that a liquid drug-polymer
formulation gel at the site of administration. Such in situ gelling
systems undergo reversible sol-gel transitions in response to
temperature, pH, or ion composition of the fluids. However,
physical blends are colloidally unstable and either phase separate
or dissociate at physiological pH. See, e.g., L Bromberg, Handbook
of Surfaces and Interfaces of Materials, H. S, Nalwa, ed., Academic
Press, 2001, Vol. 4, Chapter 7. Therefore, these blends fail to
provide a linear, sustained release of a hydrophobic or amphiphilic
compound such as imbibed or loaded drug, for example, in drug
delivery applications.
[0012] Previous structures that result from the linking of the
amphiphilic copolymers and polyelectrolyte though carbon-carbon
bond (See FIG. 1, structure I (A.) and FIG. 2 structure III, for
example) can form physical gels in water due to aggregation of the
hydrophobic segments of the amphiphilic copolymers at certain
temperatures and concentrations. However, by definition, previous
gels are unstable upon dilution due to dissociation of the physical
aggregates below a certain concentration. Accordingly, due to
dissociation under physiological conditions, previous gels were not
able to provide a linear, sustained release of a hydrophobic or
amphiphilic compound such as imbibed or loaded drug, for example,
in drug delivery applications. Further, previous structures that
result from chemical linking on both termini (See FIG. 1, structure
II (B.), for example) can form stable, chemically cross-linked
networks. However, due to the steric constrains imposed by chemical
linking on both termini, the hydrophobic parts of the amphiphilic
copolymer are unable to aggregate at well-defined temperatures and
concentrations. Therefore, nanosized aggregates do not form within
the gel network. As a result, such previous gels also were not able
to provide a linear, sustained release of a hydrophobic or
amphiphilic compound such as imbibed or loaded drug, for example,
in drug delivery applications.
SUMMARY OF THE INVENTION
[0013] A responsive microgel is provided which responds
volumetrically and reversibly to a change in one or more aqueous
conditions selected from the group consisting of (temperature, pH,
and ionic conditions) comprised of an ionizable network of
covalently cross-linked homopolymeric ionizable monomers wherein
the ionizable network is covalently attached to an amphiphilic
copolymer to form a plurality of `dangling chains` and wherein the
`dangling chains` of amphiphilic copolymer form immobile
micelle-like aggregates in aqueous solution.
[0014] A responsive microgel is further provided that comprises at
least one therapeutic entity and delivers a substantially linear
and sustained release of the therapeutic entity under physiological
conditions.
[0015] A responsive microgel is also provided wherein the ionizable
network of covalently cross-linked homopolymeric ionizable monomers
is selected from the group consisting essentially of (poly(acrylic
acid), poly(methcarylic acid), poly(4-vinylpyridinium alkyl
halide), poly(sodium acrylate), poly(sodium methacrylate),
sulfonated polyisoprene, and sulfonated polystyrene).
[0016] A further responsive microgel is provided wherein an
amphiphilic copolymer is comprised of (poly(ethylene oxide) and a
monomer selected from the group consisting essentially of
(poly(propylene oxide), poly(butylene oxide), polystyrene,
polyisobutylene, poly(methyl methacrylate), and poly(tert-butyl
acrylate)).
[0017] A method of making a responsive microgel is also provided
comprising:
[0018] a) providing, an ionizable monomer, a divinyl cross-linker,
a free radical, and a amphiphilic copolymer; and
[0019] b) copolymerizing the ionizable monomer with the divinyl
cross-linker to produce an ionizable network, while
[0020] c) abstracting hydrogen from the amphiphilic copolymer with
the free radical to progress a chain transfer reaction wherein the
amphiphilic copolymer is covalently bonded onto the ionizable
network to produce the responsive microgel.
[0021] A method of administering an effective amount of at least
one therapeutic entity to a patient is further provided which
comprises administering a responsive microgel comprising an
effective amount of at least one therapeutic entity.
[0022] A method is provided for administering at least one
therapeutic entity to a patient which entity is selected from the
group consisting of substrates of ABC transporters such as
P-glycoprotein, MRP1-MRP9; ABC half-transporters such as BCRP;
other transporters that are involved into a limited drug transport
across small intestinal epythlium; cerebral endothelium and other
barrier tissues in the body, as well as substrates of metabolic
enzyme isoforms without limitation, cytochrome P-450; esterase;
epoxide hydrolase; alcohol dehydrogenase; aldehyde dehydroganase;
dihydropyrimidine dehydroganase; NADPH-quinone oxidoreductase;
uridine 5'-triphosphat glucoronosyltransferase; sulfotransferase;
glutatione S-transferase; N-acetiltransferase; histamine
methyltransferase; catechol-o-methyl transferase; thiopurine
methyltransferase. This group of therapeutic agents include without
limitation doxorubicin and other anthracyclines, mitoxantrone,
mitomycin C, metatrexate, paclitaxel, docetaxel and other taxanes,
topotecan ant other camptotecines, cysplatin, carboplatin,
oxaliplatin and other platinum complexes; megesterol acetate and
other steroids; carvedilol and other beta-blocking agents;
azidothymidine, fludarabine and other nucleoside containing agents
in their dephospho, mono-, di- and tri-phosphorylated forms;
vinblastine, vincristine and other vinka alkaloids; etoposide and
other podophilotoxins.
BRIEF DESCRIPTION OF THE FIGURES
[0023] FIG. 1 shows previous structures (A.) (structure I) and (B.)
(structure II) that result from the linking of amphiphilic
copolymers and polyelectrolyte though carbon-carbon bonds.
[0024] FIG. 2 shows another previous structure (structure III) that
results from the linking of amphiphilic copolymers and
polyelectrolyte though carbon-carbon bonds.
[0025] FIG. 3 is a general macro-illustration of the overall
ionizable network and the covalently attached `dangling chains`
(amphiphilic copolymer) structure of the responsive microgel
described herein.
[0026] FIG. 4 is a flowchart illustration of one-step synthesis of
responsive microgels of the present invention.
[0027] FIG. 5 shows the kinetics of the release of doxorubicin and
PLURONIC.RTM. L61 through dialysis membrane with and without a
responsive microgel described in Example I.
[0028] FIG. 6 shows the kinetics of the drug diffusion in the
control experiment described in Example I.
[0029] FIG. 7 shows the kinetics of doxorubicin release from a
responsive microgel.
[0030] FIG. 8 shows a very slow, sustained release of PLURONIC.RTM.
L61 from an example responsive microgel of the present
invention.
[0031] FIG. 9 shows the results of equilibrium swelling
experiments, e.g., high absorbency as a function of the subchain
length.
[0032] FIG. 10 shows equilibrium swelling of microgel particles in
deionized water at 15.degree. and 37.degree. C. as a function of
pH. Degree of cross-linking in molar percent is indicated.
[0033] FIG. 11 shows equilibrium swelling of microgel particles in
deionized water at pH 7.0 as a function of temperature. Degree of
cross-linking in molar percent is indicated.
[0034] FIG. 12 shows the effect of temperature on hydrophobic
compounds in responsive microgel suspension.
[0035] FIG. 13 shows the equilibrium uptake of doxorubicin by
microgels of the present invention as a function of pH at
37.degree. C.
[0036] FIG. 14 shows transepithelial transport of doxorubicin from
the basolateral to the apical (b.fwdarw.a) and from the apical to
the basolateral (a.fwdarw.b) side of the Caco-2 monolayers. Initial
concentration of doxorubicin in the donor compartment was 3 .mu.M,
and the doxorubicin concentration in the receiver compartment was
assayed by fluorescence (Fl, filled points) or HPLC (open points).
Besides doxorubicin in the donor compartment, no further additive
was applied in DMEM. The transport was characterized by linear fits
(R.sup.2>0.98 in all cases). The apparent permeability obtained
by the fluorescence and HPLC assay in the b.fwdarw.a tests was
(2.81.+-.0.03).times.10.sup.-6 and (2.75.+-.0.03).times.10.sup.-6
cm/s, respectively, while the P.sub.a values obtained in the
a.fwdarw.b tests were (6.07.+-.0.04).times.10.sup.-7 and
(5.79.+-.0.04).times.10.sup.-7 cm/s using fluorescence and HPLC
assays, respectively. Typically, the transport experiments did not
exceed 2.5 h in duration.
[0037] FIG. 15 shows cumulative transport of .sup.14C-mannitol (MW
182.2 Da) across Caco-2 cell monolayers. Data are expressed as mean
.+-.S.D. of three to five experiments.
[0038] FIG. 16 shows the effect of polymers (0.5 mg/mL each) on
TEER of Caco-2 cell monolayers. Inset shows TEER recovery of Caco-2
cell monolayers after removal of the polymers. Data are expressed
as mean .+-.S.D. of three to five experiments.
DETAILED DESCRIPTION OF THE INVENTION
[0039] The present invention relates to stable chemically
cross-linked networks (gels) of a polyelectrolyte wherein `dangling
chains` of at least one amphiphilic co-polymer are bonded thereto
through carbon-carbon bonding. The dangling chains are capable of
forming intra-network micelle-like aggregates. The aggregates
possess the ability to imbibe a large quantity of, for example,
hydrophobic or amphiphilic compounds. Due to the formation of mixed
aggregates, the responsive-microgel networks of the present
invention display linear and sustained release of hydrophobic or
amphiphilic compounds in aqueous milieu. Further, the formation of
micelle-like aggregates within the chemically cross-linked
polyelectrolyte network of the present invention is reversible.
[0040] The responsive microgel described herein is, for example,
(1) able to imbibe large quantities of at least one ionic,
amphiphilic, or hydrophobic compound, and (2) forms micelle-like
aggregates within its structure when in aqueous solution and (3)
allows for a sustained, substantially linear release of the
compound in vitro and/or in vivo, for example, under the
temperature, pH, and ionic composition of physiological conditions.
A preferred embodiment of the present invention is method of
delivering an effective amount of at least one therapeutic agent to
a patient comprising administering an effective amount of a
responsive microgel of the present invention, which comprises at
least one therapeutic agent. The responsive microgels of the
present invention are suitable for oral administration, for
example, and hence the oral delivery of therapeutic agents.
[0041] Drug release kinetics from example responsive microgels of
the present invention are provided herein. Example I shows that
loading of corresponding drugs into a responsive microgel greatly
affected the kinetics of release. The drugs loaded into the
microgel exhibited slow, sustained release kinetics. Kinetics of
doxorubicin release from a responsive microgel is shown in FIG. 7.
Three cationic and one uncharged drug was loaded onto the microgel
in Example VII, all of which are currently in clinical use as
anticancer drugs. Doxorubicin, mitoxantrone, and mitomycin C are
mono-, di-, and trivalent cationic weak bases, respectively. Taxol
is uncharged (hydrophobic). The ability of responsive microgels of
the invention to effectively load and hold taxol, combined with
mucoadhesive properties is a feature important for delivery of
taxol and other hydrophobic solutes such as steroid hormones. The
taxol loading capacity provides additional evidence to the
mechanism of taxol solubilization into micelle-like aggregates
within the responsive microgels. Drug loading via ion-exchange are
illustrated using the potent chemotherapeutic drug doxorubicin.
[0042] The responsive microgel of the present invention comprises
two responsive components: An amphiphilic copolymer (nonionic
copolymer) capable of aggregation in response to a change in
temperature; and, an ionizable, covalently cross-linked polymeric
network of monomers which responds volumetrically to changes in
aqueous conditions such as pH or ionic composition by swelling or
collapsing. Since both responsive components, i.e., the nonionic
copolymer and the cross-linked polymermeric network of monomers
which contain ionizable groups are bound through covalent bonds,
each polymer has a chemical or mechanical influence over the
swelling of the other polymeric component. The resulting responsive
microgel exhibits volumetric changes in response to variations in
pH as well as temperature. See, Examples III-V. These responsive
microgel graft-comb copolymers dissolve freely in aqueous solutions
and self-assemble in response to changes in conditions such as pH
and temperature.
[0043] The microgel covalently cross-linked polymer network of the
present invention is comprised of at least one amphiphilic
copolymer covalently attached (preferably a carbon-carbon bond from
a single terminal region of each amphiphilic copolymer) to an
ionizable network (polyelectrolyte). The amphiphilic copolymer
forms the `dangling chain` component of the responsive microgel
which forms micelle-like aggregates within the covalently
cross-linked polymer network in aqueous solution. See, FIG. 3
(structure of the responsive microgel).
[0044] The term "responsive" in reference to the microgel of the
present invention refers to reversible phase transition
characteristics, e.g., volumetric change, which result from
exposure to a change in one or more environmental factors under
aqueous conditions, such as temperature, pH, and ionic conditions.
The microgels operate as described herein within the temperature
range of about -4.degree. C. to about 55.degree. C., preferably
from about 0 to about 37.degree. C. The microgels will be collapsed
at pH 1-3 such as in stomach and swollen at pH exceeding the pKa of
their carboxylic groups, i.e. at pH>4.5 (fully swollen at pH
7.4, for example). The gel is collapsed (swelling degree preferably
not exceeding 50 v/v % of water per polymer) at acidic pH such as
in stomach, but fully swollen (swelling degree preferably exceeding
100-5000 v/v % of liquid per polymer) in the intestine. The gels
protect the therapeutic entity, e.g., embedded drug, and hold it
without release when collapsed, but rapidly release when swollen.
The range of operation of the microgels of the present invention
are solutions of ionic strength preferably below 1 M, or from 0M to
5 M, for example. A change in these environmental factor(s) affects
the responsive microgel by causing the structure to undergo a
reversible volumetric change in which the gel increases volume by
expanding (swelling) or decreases volume by collapsing
(contraction).
[0045] Phase transitions in gels may be explained, for example, by
the following equation. One may determine the effect of ionic
groups on the reduced chemical potential (.DELTA..mu..sub.1) for
solvent in an isotropically swollen gel network: .DELTA. .times.
.times. .mu. 1 = .times. ( .mu. 1 - .mu. 1 0 ) / RT = ln .function.
( 1 - v 2 ) + v 2 .times. f .function. ( .lamda. ) + .DELTA.
.times. .times. .mu. i RT = ln .times. .times. a i + .chi. .times.
.times. v 2 2 + ##EQU1## where a.sub.1 is the activity of the
solvent in the network, .chi. is the interaction parameter, v.sub.2
is the volume fraction of the polymer, f(.lamda.) is the function
of the deformation tensor, .DELTA..mu..sub.i is the contribution to
the total chemical potential by the presence of ionic groups on the
chains.
[0046] Example I describes the favorable linear release of
monomeric PLURONIC.RTM. from the microgels. It was discovered that
PLURONIC.RTM. 161, for example, has exceptionally low release rate
and sustained release for over 10 days due to the formation of
mixed micelles between added PLURONIC.RTM. 161 and PLURONIC.RTM.
covalently grafted to a poly(acrylic acid) network in the process
of synthesis. Such mixed, immobile micelles can provide
thermodynamically stable environment for the PLURONIC.RTM. solute,
making its effective partition coefficient between micelles and
water to be very low. These results are unique and exceptionally
well suited for the intended application of the novel microgels in
drug delivery.
[0047] Compositions
[0048] 1. Ionizable Network
[0049] The ionizable network is a covalently cross-linked
homopolymeric network of ionizable monomers. The monomers of the
ionizable network each contain at least one ionizable group. The
ionizable network responds volumetrically to changes in aqueous
conditions such as pH or ionic composition by swelling or
collapsing. Preferred embodiments of this polyelectrolyte network
(onto which the amphiphilic copolymer `dangling chains` are
attached via C--C bond to form the responsive microgel) are
comprised of a monomer selected from the group consisting
essentially of (poly(acrylic acid), poly(methcarylic acid),
poly(4-vinylpyridinium alkyl halide), poly(sodium acrylate),
poly(sodium methacrylate), sulfonated polyisoprene, and sulfonated
polystyrene).
[0050] Preferred polyanion-forming compounds include poly(acrylic
acid), poly(methcarylic acid), and poly(2-ethylacrylic acid);
preferred polycation-forming compounds include polyethyleneimine
and polyethylenepiperazine. The hydrophilic blocks recited infra,
(i.e., A. Hydrophilic Monomers and Polymers), can also be used in
the compositions described herein either as an element of the
ionizable network (polyelectrolyte).
[0051] A. Polyanion Forming Compounds
[0052] Ionizable compounds for the ionizable network of the present
invention also include, but are not limited to, polyanion-forming
compounds such as poly(acrylic acid), poly(methacrylic acid),
poly(maleic acid), poly(styrenesulfonic acid), poly(itaconic acid),
poly(vinyl sulfate), poly(vinylsulfonic acid), poly(vinyl
phosphate), poly(acrylic acid-co-maleic acid), poly(styrenesulfonic
acid-co-maleic acid), poly(ethylene-co-acrylic acid),
poly(phosphoric acid), poly(silicic acid), hectorite, bentonite,
alginic acid, pectic acid, kappa-, lambda- and iota-carrageenans,
xanthan, gum arabic, dextran sulfate, carboxymethyldextran,
carboxymethylcellulose, cellulose sulfate, cellulose xanthogenate,
starch sulfate and starch phosphate, lignosulfonates, karaya gum;
polygalacturonic acid, polyglucuronic acid, polyguluronic acid,
polymannuronic acid and copolymers thereof; chondroitin sulfate,
heparin, heparan sulfate, hyaluronic acid, dermatan sulfate,
keratan sulfate; poly-(L)-glutamic acid, poly-(L)-aspartic acid,
deoxyribonucleic acid, ribonucleic acid, acidic gelatins
(A-gelatins); starch, amylose, amylopectin, cellulose, guar, gum
arabic, karaya gum, guar gum, pullulan, xanthan, dextran, curdlan,
gellan, carubin, agarose, as well as chitin and chitosan
derivatives having the following functional groups in various
degrees of substitution: carboxymethyl and carboxyethyl,
carboxypropyl, 2-carboxyvinyl, 2-hydroxy-3-carboxypropyl,
1,3-dicarboxylsopropyl, sulfomethyl, 2-sulfoethyl, 3-sulfopropyl,
4-sulfobutyl, 5-sulfopentyl, 2-hydroxy-3-sulfopropyl,
2,2-disulfoethyl, 2-carboxy-2-sulfoethyl, maleate, succinate,
phthalate, glutarate, aromatic and aliphatic dicarboxylates,
xanthogenate, sulfate, phosphate, 2,3-dicarboxy,
N,N-di(phosphatomethyl)aminoethyl,
N-alkyl-N-phosphatomethylaminoethyl. These derivatives may
additionally comprise nonionic functional groups in various degrees
of substitution, such as methyl, ethyl, propyl, isopropyl,
2-hydroxyethyl, 2-hydroxypropyl and 2-hydroxybutyl groups, for
example, as well as esters with aliphatic carboxylic acids, e.g.,
(C.sub.2 to C.sub.18).
[0053] B. Polycation Forming Compounds
[0054] Examples of polycation-forming compounds for the ionizable
network of the present invention also include, but are not limited
to, poly(alkylenimines), especially poly(ethylenimine),
poly-(4-vinylpyridine), poly(2-vinylpyridine),
poly(2-methyl-5-vinylpyridine),
poly(4-vinyl-N--C.sub.1-C.sub.18-alkylpyridinium salt),
poly(2-vinyl-N--C.sub.1-C.sub.18-alkylpyridinium salt),
polyallylamine, polyvinylamine, aminoacetylated polyvinyl alcohol;
the polysulfone dialkylammonium salts; basic proteins,
poly-(L)-lysine, poly-(L)-arginine, poly(ornithine), basic gelatins
(B-gelatins), chitosan; chitosan with various degrees of
acetylation; starch, amylose, amylopectin, cellulose, guar, gum
arabic, karaya gum, guar gum, dextran, pullulan, xanthan, curdlan,
gellan, carubin, agarose, as well as chitin and chitosan
derivatives having the following functional groups in various
degrees of substitution: 2-aminoethyl, 3-aminopropyl,
2-dimethylaminoethyl, 2-diethylaminoethyl, 2-diisopropylaminoethyl,
2-dibutylaminoethyl, 3-diethylamino-2-hydroxypropyl,
N-ethyl-N-methylaminoethyl, N-ethyl-N-methylaminopropyl,
2-diethylhexylaminoethyl, 2-hydroxy-2-diethylaminoethyl,
2-hydroxy-3-trimethylammonionopropyl,
2-hydroxy-3-triethylammonionopropyl, 3-trimethylammonionopropyl,
2-hydroxy-3-pyridiniumpropyl and S,S-dialkylthioniumalkyl. These
derivatives may additionally comprise nonionic functional groups in
various degrees of substitution, such as methyl, ethyl, propyl,
isopropyl, 2-hydroxymethyl, 2-hydroxypropyl and 2-hydroxybutyl
groups, for example, and also esters with aliphatic carboxylic
acids (C.sub.2 to C.sub.18); and also n,m-ionenes, poly(aniline);
poly(pyrrole); poly(viologens) and also poly(amidoamines) based on
piperazine.
[0055] II. Amphiphilic Copolymer
[0056] A preferred amphiphilic copolymer (nonionic copolymer)
component for use in the methods and compositions in the present
invention is a copolymer of an ionizable monomer and a hydrophobic
monomer. The amphiphilic copolymer is preferably comprised of a
nonionic hydrophilic monomer and nonionic hydrophobic monomer.
Amphiphilic copolymers for use in constructing microgels of the
present invention are selected from amphiphilic diblock copolymers,
amphiphilic triblock copolymers, amphiphilic multiblock copolymers,
and amphiphilic graft copolymers. The amphiphilic copolymer is
preferably a di- or triblock copolymer. The amphiphilic copolymer
is preferably comprised of (poly(ethylene oxide) and a monomer
selected from the group consisting essentially of (poly(propylene
oxide), poly(butylene oxide), polystyrene, polyisobutylene,
poly(methyl methacrylate), and poly(tert-butyl acrylate)).
[0057] Amphiphilic copolymers for use in constructing responsive
microgels of the present invention generally have a molecular
weight in the range of from about 200 to about 1,000,000,
preferably from about 500 to about 500,000, and more preferably
from about 200 to about 200,000. The amphiphilic copolymers
generally have a hydrophilic/lipophilic balance in the range of
from about 0.001 to about 100.
[0058] A preferred embodiment of the present invention comprises an
amphiphilic copolymer comprised of a diblock, triblock, or
multiblock copolymer, preferably a diblock or triblock copolymer,
more preferably a diblock copolymer. A particularly preferred
embodiment comprises a triblock copolymer wherein one block
comprises polyoxyethylene. Another particularly preferred
embodiment comprises a triblock copolymer wherein one block
comprises polyoxypropylene.
[0059] Any of the hydrophilic blocks of various chemistry and
formula weight of the amphiphilic copolymers herein can be used in
combination with any of the hydrophobic blocks of various chemistry
and formula weight to compose an amphiphilic `dangling chain`. The
hydrophilic blocks recited infra (i.e., A. Hydrophilic Monomers and
Polymers) can be used in the compositions described herein either
as an element of the ionizable network (polyelectrolyte) and/or an
element of an amphiphilic `dangling chain` copolymer.
[0060] The hydrophilic blocks of the amphiphilic diblock, triblock,
or multiblock copolymers can have formula weights in the range from
about 200 to about 500,000, preferably from about 2,500 to about
250,000, more preferably from about 500 to about 100,000. The
hydrophobic blocks of the amphiphilic diblock, triblock, or
multiblock copolymers useful in the present invention can have
formula weights in the range of from about 1,000 to about 500,000,
preferably from about 2,500 to about 250,000, more preferably from
about 500 to about 100,000.
[0061] Amphiphilic graft copolymers useful in the present invention
possess rotatable side chain block regions that can rotate or fold
to become part of the aggregates within the microgels of the
present invention. The number of side chains present in each of the
amphiphilic graft copolymers can be in the range of from about 1 to
about 10000. The formula weights of the various blocks in the
amphiphilic copolymers can be varied independently of each
other.
[0062] A. Hydrophilic Monomers and Polymers
[0063] Examples of monomer repeat units that can be used in the
preparation of hydrophilic blocks of the amphiphilic copolymer (or
as monomers of the ionizable network) are set forth as follows.
Poly(acrylic acid) and poly(metal acrylates) are preferred.
[0064] 1. Example Monomer Units Useful as Repeat Units in
Hydrophilic Blocks TABLE-US-00001 Polyacrylic acid Poly(metal
acrylate), M = Li, Na, K, Cs Polyacrylamide Poly(methacrylic acid),
R = H, alkyl Poly(metal methacrylate) Polymethacrylamide M = Li,
Na, K, Cs R = H, alkyl Polystyrene sulfonic acid Polystyrene
sulfonic acid metal salt, M = Li, Na, K, Cs Polystyrene carboxylic
Polystyrene carboxylic acid, metal acid salt M = Li, Na, K, Cs
Poly(vinyl alcohol), R = H, alkyl Poly(4-vinyl-N- R = H, alkyl
alkyllpyridinium halide), Poly(2-vinyl-N-alkyllpyridinium
halide)\Poly(hydroxyethyl methacrylate) Poly(itaconic acid)
Poly(N,N,N-trialkyl-4-vinylphenylammonium halide)
Poly(N,N,N-trialkyl-4-vinylbenzylammonium halide) Percent
quaternization 10% to 70%
Poly(N,N,N-trialkyl-4-vinylphenethylammonium halide)
Poly(L-glutamic acid) Poly(L-aspartic acid) Hyaluronic acid
[0065] Amino acids used to compose hydrophilic blocks of the
amphiphilic copolymer: TABLE-US-00002 Serine Threonine Tyrosine
Lysine Arginine Histidine Aspartic acid Glutamic acid
[0066] 2. Example Polymers Useful as Hydrophilic Blocks
Polymers as hydrophilic blocks of the nonionic copolymer
(amphiphilic copolymer) for employment in the `dangling chains` of
the responsive microgel of the present invention also include, but
are not limited to:
[0067] Poly(sodium 1-carboxylatoethylene),
Poly(5-hydroxy-1-pentene), 5,8-poly-5,7-dodecadiynediol,
10,13-poly-10,12-heptacosadiynoic acid, 2,5-poly-2,4-hexadienedioic
acid, 2,5-poly-2,4-hexadienoic acid,
(6-amino)-2,5-poly-2,4-hexadienoic acid,
(6-amino)2,5-poly-2,4-hexadienoic acid, hydrochloride,
2,5-poly-2,4-hexadiynediol, 10,13-poly-10,12-nonacosadiynoic acid,
2,5-poly-2,4,6-octatriynediol, 10,13-poly-10,12-pentacosadiynoic
acid, 2,5-poly-5-phenyl-2,4-pentadienoic acid,
Poly(2-aminoisobutyric acid), dichloroacetic acid complex,
Poly(L-arginine), Poly(L-nitroarginine), Poly(L-aspartic acid),
Poly(beta-benzyl-L-aspartic acid),
Poly[beta-(p-chloro-benzyl)-L-aspartic acid],
Poly(beta-ethyl-L-aspartic acid),
Poly[beta-(2-phenyl-ethyl)-L-aspartic acid],
Poly(alpha-isobutyl-L-aspartic acid),
Poly(beta-N-propyl-L-asparticacid), Poly(2,4-diaminobutyricacid),
Poly(N-benzyloxycarbonyl-2,4-diaminobutyric acid), Poly(D-glutamic
acid), Poly(gamma-benzyl-D-glutamic acid),
Poly(gamma-m-chloro-benzyl-D-glutamic acid),
Poly(gamma-o-chloro-benzyl-D-glutamic acid),
Poly(gamma-p-chloro-benzyl-D-glutamic acid),
Poly(gamma-methyl-D-glutamic acid),
Poly(gamma-phthalimidomethyl-L-glutamic acid),
Poly(gamma-N-amyl-L-glutamic acid), Poly(gamma-benzyl-L-glutamic
acid), Poly(gamma-m-chloro-benzyl-L-glutamic acid),
Poly(gamma-o-chloro-benzyl-L-glutamic acid),
Poly(gamma-p-chloro-benzyl-L-glutamic acid),
Poly(gamma-N-butyl-L-glutamic acid),
Poly(gamma-N-dodecyl-L-glutamic acid),
Poly(gamma-N-ethyl-L-glutamic acid),
Poly[gamma-N-(2-chloro-ethyl)-L-glutamic acid],
Poly[gamma-N-(2-phenyl-ethyl)-L-glutamic acid],
Poly(gamma-N-hexyl-L-glutamic acid), Poly(gamma-methyl-L-glutamic
acid), Poly(gamma-methyl-L-glutamic acid), dimethyl phthalate
complex, Poly(gamma-N-octyl-L-glutamicacid),
Poly(gamma-N-propyl-L-glutamic acid),
Poly[gamma-N-(3-phenyl-propyl)-L-glutamic acid], Poly(L-glutamine),
Poly[N5-(4-hydroxybutyl)-L-glutamine],
Poly[N5-(2-hydroxyethyl)-L-glutamine],
Poly[N5-(3-hydroxypropyl)-L-glutamine], Poly(D-glutamyl-L-glutamic
acid), Poly(gamma-benzyl-D-glutamyl-L-glutamic acid),
Poly(gamma-ethyl-D-glutamyl-L-glutamic acid),
Poly[gamma-(2-phenyl-ethyl)-D-glutamyl-L-glutamic acid],
Poly(L-histidine), Poly(1-benzyl-L-histidine), Poly(L-histidine),
hydrochloride, Poly(gamma-hydroxy-L-alpha-aminoveleric acid),
Poly(L-lysine), Poly(E-benzyloxycarbonyl-L-lysine), Poly(L-lysine),
hydrobromide, Poly(L-methionine-s-carboxymethylthetin),
Poly(L-methionine-s-methylsulfonium bromide), Poly(L-serine),
Poly(gamma-hydroxy-L-proline), Poly(hydroxymethylene),
Poly(1-hydroxytrimethylene),
Poly(3,3-bishydroxymethyltrimethyleneoxide),
Poly(3-hydroxytrimethyleneoxide), Poly(vinyl alcohol),
Poly(ethylene glycol), Poly(2-methyl-vinyl alcohol),
Poly(hydroxymethylene), Poly(cinnamic acid), Poly(crotonic acid),
Poly(3-bromo acrylic acid), Poly(3-ethyl acrylic acid),
Poly(N-acetyl-alpha-amino acrylic acid), Poly(alpha-bromoacrylic
acid), Poly(alpha-chloroacrylic acid), Poly(alpha-fluoroacrylic
acid), Poly(sodium alpha-chloroacrylate),
Poly(3-oxa-5-hydroxypentyl methacrylate), Poly(2-hydroxyethyl
acrylate), Poly(2-hydroxypropyl acrylate),
Poly(beta-chloro-2-hydroxypropyl acrylate),
Poly[N-(2-hydroxyethyl)-3,6-dichlorocarbazolyl acrylate],
Poly[N-(2-hydroxyethyl)carbazolyl acrylate],
Poly(acryloyl-beta-hydroxyethyl-3,5-dimitrobenzoat),
Poly(methacryloyl-beta-hydroxyethyl-3,5-dimitrobenzoat),
Poly(N-(2-hydroxyethyl)carbazolyl methacrylate),
Poly(2-hydroxyethyl methacrylate), Poly(2-hydroxypropyl
methacrylate), Poly(3-methoxy-2-hydroxypropyl methacrylate),
Poly[1-(2-hydroxyethyl)pyridiniumbenzene sulfonate methacrylate],
Poly[1-(2-hydroxyethyl)trimethylamoniumbenzene sulfonate
methacrylate], Poly[N-(2-hydroxyethyl)phthalimido methacrylate],
Poly[N-(hydroxyethyl)carbazolyl methacrylate],
Poly(N-ethyl-3-hydroxymethylcarbazolyl methacrylate),
Poly(2-sulfonic acid-ethyl methacrylate), Poly(2-trimethylammonium
ethyl methacrylate chloride), Poly(2-trimethylammoniummethyl
methacrylate chloride), Poly(methacrylonitrile), Poly(thiolacrylic
acid), Poly(acrylonitrile), Poly(acrylamide), Poly(methacrylamide),
Poly(N,N-dimethylacrylamide), Poly[(N-methylol)acrylamide],
Poly[N-methoxymethyl methacrylamide], Poly(N-methyl
methacrylamide), Poly(N-2-methoxyethyl methacrylamide),
Poly[N-(2-hydroxypropyl)methacrylamide],
Poly(2-methylpropanesulfonate sodium 2-acrylamido),
Poly(2-methylpropanesulfonic acid 2-acrylamido),
Poly[(p-amino)-styrene], Poly[4-(4-hydroxybutoxymethyl)styrene],
Poly[4-(2-hydroxyethoxymethyl)styrene],
Poly[4-(2-hydroxyiminoethyl)styrene],
Poly[4-(1-hydroxyiminoethyl)styrene],
Poly[4-(n-2-hydroxybutyl)styrene],
Poly[4-(1-hydroxy-3-dimethylaminopropyl)styrene],
Poly[4-(1-hydroxy-1-methylbutyl)styrene],
Poly[4-(1-hydroxy-1-methylethyl)styrene],
Poly[4-(1-hydroxy-1-methylhexyl)styrene],
Poly[4-(1-hydroxy-1-methylpentyl)styrene],
Poly[4-(1-hydroxy-1-methylpropyl)styrene],
Poly(2-hydroxymethylstyrene), Poly(3-hydroxymethylstyrene),
Poly(4-hydroxymethylstyrene), Poly(4-hydroxystyrene),
Poly[p-1-(2-hydroxybutyl)-styrene],
Poly[p-1-(2-hydroxypropyl)-styrene],
Poly[p-2-(2-hydroxypropyl)-styrene],
Poly[4-(1-hydroxy-3-morpholinopropyl)styrene],
Poly[4-(1-hydroxy-3-piperidinopropyl)styrene],
Poly(p-octylaminesulfonate styrene), Poly(2-carboxystyrene),
Poly(4-carboxystyrene), Poly(styrene sulfonic acid), Poly(vinyl
sulfonic acid), Poly[N-(2-hydroxypropyl)methacrylamide],
Poly[oxy(hydroxyphosphinylidene)], Poly(9-vinyladenine), Poly(vinyl
carbanilate), Poly(vinylpyrrolidone), Poly(vinyl succinamic acid),
Poly(N-isopropylacrylamide), Poly(methacrylic acid), Poly(itaconic
acid), Poly(glycidyl methyl itaconate), Poly(monomethyl itaconate),
Poly[N-(p-chlorophenyl)itaconimide], Poly[N-(p-tolyl)itaconimide],
Poly[N-(2-chloroethyl)itaconimide],
Poly[N-(4-acetoxyphenyl)itaconimide],
Poly[N-(4-chlorophenyl)itaconimide],
Poly[N-(4-ethoxycarbonylphenyl)itaconimide],
Poly(N-benzylitaconimide), Poly(N-butylitaconimide),
Poly(N-ethylitaconimide), Poly(N-isopropylitaconimide),
Poly(N-isobutylitaconimide), Poly(N-methylitaconimide),
Poly(N-naphthylitaconimide), Poly(N-phenylitaconimide),
Poly(N-propylitaconimide), Poly(N-tolylitaconimide),
Poly(alpha-chlorovinyl acetic acid), Poly(carboxychloromethyl
ethylene), Poly(4-vinyl phenol), Poly(o-hydroxy-vinylphenylketone),
Poly(alpha-phenylvinyl phosphonic acid),
Poly[(1,2,5-trimethyl-4,4i-hydroxypyridiumchlorideethynyl)ethylene-
], Poly(allyl alcohol), Poly(acrylic acid), Poly[2-(3-sodium
sulfonato-2-methylpropyl)methacrylamide], Poly(3-sodium
sulfonatopropyl methacrylate), Poly(3-oxa-5-hydroxypentyl
methacrylate), Poly(diethylenegycol dimethacrylate),
Poly(trimethyleneglycol dimethacrylate), Poly(triethyleneglycol
dimethacrylate), Poly(ethyleneglycol N-phenylcarbamate
methacrylate), Poly(acryloyl-L-glutamic acid),
Poly(methacryloyl-L-glutamic acid), Poly(butadiene-1-carboxylic
acid), Poly(crotonate acid), Poly(trans-4-ethoxy-2,4-pentadienoic
acid), Poly(alpha-phenylvinyl phosphonic acid), Poly(vinylbenzoic
acid), Poly(2-acryloyloxy benzoic acid),
Poly[1-(2-hydroxyethylthio)-1,3-butadiene], Poly(2,5-dicarboxylic
acid-1-hexene), Poly(3-hydroxyisoprene), Poly(alpha-phenylvinyl
phosphonic acid), Poly(2-chloro-3-hydroxy propene),
Poly(2-p-vinylphenylpropanol), Poly(o-hydroxy-vinylphenylketone),
Poly(1-vinyl-3-benzyl-imidazolium chloride),
Poly(4-vinylbenzyltrimethylammonium chloride),
Poly(4-vinylbenzyldimethyl vinylbenzyl ammonium chloride),
Poly(4-vinylbenzyldimethyl methacryloyl ammonium chloride),
Poly(4-vinylbenzyldimethyl acryloyl ammonium chloride),
Poly(4-vinylbenzyldimethyl allyl ammonium chloride),
Poly(4-vinylphenyltrimethylammonium chloride), Poly(4-vinylphenyl
dimethyl vinylbenzyl ammonium chloride), Poly(4-vinylphenyl
dimethyl methacryloyl ammonium chloride), Poly(4-vinylphenyl
dimethyl acryloyl ammonium chloride), Poly(4-vinylphenyl dimethyl
allyl ammonium chloride), Poly(4-vinylphenethyltrimethylammonium
chloride), Poly(4-vinylphenethyldimethyl vinylbenzyl ammonium
chloride), Poly(4-vinylphenethyldimethyl methacryloyl ammonium
chloride), Poly(4-vinylphenethyldimethyl acryloyl ammonium
chloride), Poly(4-vinylphenethyldimethyl allyl ammonium chloride),
Poly(vinyl acetate), Poly(vinyl butyral), Poly(acetaldehyde),
Poly(ethylene oxide), Poly(2-cyanoethyloxymethylene oxide),
Poly[(methoxymethyl)ethylene oxide], Poly(methylene sulfide),
Poly(ethylene disulfide), Poly(ethylene sulfide), Poly(ethylene
tetrasulfide), Poly(methylene disulfide), Poly(trimethylene
disulfide), Poly(ethylene amine), Poly(propylene amine),
Poly(4-vinyl-N-methylpyridinium chloride),
Poly(4-vinyl-N-ethylpyridinium chloride),
Poly[4-(2-dimethylaminoethoxycarbonyl)styrene], hydrochloride,
Poly(4-vinylpyridine), hydrogen chloride,
Poly(4-vinyl-N-vinylbenzylpyridinium chloride),
Poly(4-vinyl-N-methacryloylpyridinium chloride),
Poly(4-vinyl-N-acryloylpyridinium chloride),
Poly(4-vinyl-N-allylpyridinium chloride),
Poly(2-vinyl-N-methylpyridinium chloride),
Poly(2-vinyl-N-ethylpyridinium chloride),
Poly(2-vinyl-N-vinylbenzylpyridinium chloride),
Poly(2-vinyl-N-methacryloylpyridinium chloride),
Poly(2-vinyl-N-acryloylpyridinium chloride),
Poly(2-vinyl-N-allylpyridinium chloride), and Poly(2-vinylpyridine)
hydrogen chloride.
[0068] B. Hydrophobic Monomers and Polymers
[0069] The hydrophobic blocks of the amphiphilic diblock, triblock,
or multiblock copolymers useful in the present invention can have
formula weights in the range of from about 500 to about 500,000,
preferably from about 500 to about 250,000, more preferably from
about 500 to about 100,000. Examples of monomer repeat units that
can be used in the preparation of hydrophobic blocks are set forth
as follows.
[0070] 1. Example Monomers Units Useful as Repeat Units in
Hydrophobic Blocks or Hydrophobic Repeat Units TABLE-US-00003
Poly(2-vinylnaphthalene) Poly(caprolactam), R = H, CH.sub.3, alkyl,
or aryl group Polystyrene Poly(amide) poly(p-X-styrene), X = alkyl,
CH.sub.3, t-Bu, O CH.sub.3, CH.sub.2 Cl, Cl, CN, CHO
poly(alpha-methylstyrene) poly(4-vinylpyridine)
poly(2-vinylpyridine) polybutadiene polybutadiene 1,4-addition
1,2-addition polyisoprene polychloroprene polyethylene
polypropylene polyvinylchloride polyvinylidenechloride
polyvinylfluoride polyvinylidenefluoride polyhexafluoropropene
polypropyleneoxide polypropyleneoxide poly(N-vinylcarbazol)
polytetrafluoroethane polysiloxane polyacrylates R = CH.sub.3,
alkyl or aryl group R' = CH.sub.3, any alkyl or aryl group R' =
CH.sub.3, alkyl or aryl group R = CH.sub.3, CH.sub.2 CH.sub.3,
t-Butyl, any alkyl or aryl group
[0071] Amino acids used to compose hydrophobic blocks of the
amphiphilic copolymer: TABLE-US-00004 Alanine Valine Leucine
Tryptophan Phenylalanine Methionine Proline
[0072] 2. Example Polymers Useful as Hydrophobic Blocks
[0073] Polymers as hydrophobic blocks of the nonionic copolymer
(amphiphilic copolymer) for employment in the `dangling chains` of
the responsive microgel of the present invention also include, but
are not limited to:
[0074] Poly[thio(2-chlorotrimethylene)thiotrimethylene],
Poly[thio(1-iodiethylene)thio(5-bromo-3-chloropentamethylene),
Poly[imino(1-oxoethylene)silylenetrimethylene],
Poly(oxyiminomethylenehydrazomethylene),
Poly[oxy(1,1-dichloroethylene)imino(1-oxoethylene)],
Poly[(6-chloro-1-cyclohexen-1,3-ylene)-1-bromoethylene],
Poly[(dimethylimino)ethylenebromide],
Poly[(oxycarbonyloxymethyl)ethylene], Poly(1,1-dimethylethylene),
Poly(1-methyl-1-butenylene),
Poly[(2-propyl-1,3-dioxane-4,6-diyl)methylene],
Poly[1-(methoxycarbonyl)ethylene], Poly(glycyl-6-aminocarproic
acid), Poly(glycyl-6-aminocarproic acid-3-amino-propionic acid),
Poly(L-alanyl-4-aminobutyric acid), Poly(L-alanyl-6-aminocaproic
acid), Poly(L-alanyl-3-aminopropionic acid),
Poly(L-alanyl-5-aminovaleric acid),
Poly(2-aminocyclopentylenecarboxy acid),
Poly(2-aminoethylenesulfonic acid), Poly(3-aminopropionic acid),
Poly(1-methyl-3-aminopropionic acid),
Poly[(3-aminocyclobutylene)-propionic acid],
Poly[(2,2-dimethyl-3-aminocyclobutylene)-propionic acid],
Poly(2-aminoisobutyric acid), Poly(3-aminobutyric acid),
Poly(4-aminobutyric acid), Poly(5-aminovaleric acid),
Poly(6-aminocaproic acid), Poly(D-(-)-3-methyl-6-aminocaproic
acid), Poly(6-methyl-6-aminocaproic acid), Poly(6-aminothiocaproic
acid), Poly(7-aminoenanthic acid),
Poly((R)-3-methyl-7-aminoenanthic acid),
Poly((S)-4-methyl-7-aminoenanthic acid),
Poly((R)-5-methyl-7-aminoenanthic acid),
Poly((R)-6-methyl-7-aminoenanthic acid),
Poly(N-methyl-7-aminoenanthic acid), Poly(7-aminothioenanthic
acid), Poly(8-aminocaprylic acid), Poly(9-aminopelargonic acid),
Poly(10-aminocapric acid), Poly(11-aminoundecanoic acid),
Poly(N-allyl-11-aminoundecanoic acid),
Poly(N-ethyl-11-aminoundecanoic acid),
Poly(2-methyl-11-aminoundecanoic acid),
Poly(N-methyl-11-aminoundecanoic acid),
Poly(N-phenyl-11-aminoundecanoic acid),
Poly(N-piperazinyl-11-aminoundecanoic acid),
Poly(12-aminolauricacid), Poly(aminoformicacid),
Poly(N-butyl-aminoformic acid), Poly(2-methyl-N-butyl-aminoformic
acid), Poly(N-phenyl-aminoformic acid),
Poly[imino-(1-oxo-2,3-dimethyltrimethylene)],
Poly[imino-(1-oxo-3-ethyltrimethylene)],
Poly[imino-(1-oxo-4-methylhexamethylene)],
Poly[imino-(1-oxo-3-methylhexamethylene)],
Poly[imino-(1-oxo-5-methylhexamethylene)],
Poly[imino-(1-oxo-3-methyl-6-isopropylhexamethylene)],
Poly[imino-(1-oxo-3-methyltrimethylene)],
Poly[imino-(1-oxo-3-vinyltrimethylene)],
Poly[N-(2-methylbutyl)iminocarbonyl],
Poly[N-(phenylpropyl)iminocarbonyl], Poly(N-methyldodecanelactam),
Poly(L-alanine), Poly(beta-L-alanine), Poly(N-methyl-L-alanine),
Poly(L-phenylalanine), Poly(2-butyl-2-methyl-beta-alanine),
Poly(2,2-dimethyl-beta-alanine), Poly(3,3-dimethyl-beta-alanine),
Poly(2-ethyl-2-methyl-beta-alanine),
Poly(2-methyl-2-propyl-beta-alanine),
Poly(N-isopropyl-beta-alanine), Poly(3-methyl-beta-alanine),
Poly(N-methyl-beta-alanine), Poly(N-phenyl-beta-alanine),
Poly(mathacryloyl-D-alanine), Poly(M-methacryloyl-L-alanine),
Poly(L-cysteine), Poly(L-glycine), Poly(L-leucine),
Poly(isoleucine), Poly(N-trifluoroacetal-L-lysine),
Poly(N-carbobenzoxy-L-lysine), Poly(methionine), Poly(L-tyrosine),
Poly(o-acetal-hydroxyproline), Poly(o-acetal-L-serine),
Poly(alpha-amino-n-butyric acid),
Poly(s-carbobenzoxymethyl-L-cysteine), Poly(3,4-dihydro-L-proline),
Poly(o-p-tolylsulfonyloxy-L-proline),
Poly(gamma-hydroxy-o-acetyl-L-alpha-aminoveleric acid),
Poly(L-valine), Poly(L-proline), Poly(L-proline), acid complex,
Poly(L-proline), acetic acid complex, Poly(L-proline), formic acid
complex, Poly(L-proline), propionic acid complex,
Poly(o-acetyl-hydroxy-L-proline), Poly(o-acetyl-L-serine),
Poly(o-benzyloxycarbonyl-L-tyrosine),
Poly(s-benzyloxycarbonyl-L-cysteine),
Poly(s-benzylthio-L-cysteine),
Poly(methylphosphinidene-trimethylene), Polymalonate,
Polysuccinate, Polyglutarate, Polyadipate, Poly(methylene),
Poly(diphenylmethylene), Poly(di-p-tolyl-methylene),
Poly(ethylene), Poly(chlorotrifluoroethylene),
Poly(1-butoxy-2-methyl-ethylene),
Poly(1-t-butoxy-2-methyl-ethylene),
Poly(1-ethoxy-2-methoxy-ethylene),
Poly(1-ethoxy-2-methyl-ethylene),
Poly(1-isobutoxy-2-methyl-ethylene),
Poly(1-isopropoxy-2-methyl-ethylene),
Poly(1-methoxy-2-methyl-ethylene),
Poly(1-methyl-2-propoxy-ethylene), Poly(tetrafluoroethylene),
Poly(trifluoroethylene), Poly(butylethylene),
Poly(t-butylethylene), Poly(cyclohexylethylene),
Poly(2-cyclohexylethylene), Poly[(cyclohexylmethyl)ethylene],
Poly(3-cyclohexylpropylethylene), Poly(decylethylene),
Poly(dodecylethylene), Poly(isobutyl ethylene),
Poly(neopentylethylene), Poly(4,4-dimethylpentylethylene),
Poly(nonylethylene), Poly(octylethylene), Poly(propylethylene),
Poly(propyl-2-propylene), Poly(tetradecylethylene),
Poly(vinylbromide), Poly(N-vinyl carbazole), Poly(vinyl chloride),
Poly(vinyl fluoride), Poly(vinylidene bromide), Poly(vinylidene
chloride), Poly(vinylidenefluoride), Poly(vinylcyclobutane),
Poly(vinylcycloheptane), Poly(vinylcyclohexane),
Poly(o-methoxy-vinylcyclohexane), Poly(3-methyl-vinylcyclohexane),
Poly(4-methyl-vinylcyclohexane), Poly(vinylcyclohexene),
Poly(vinylcyclohexylketone), Poly(vinylcyclopentane),
Poly[3-(2-vinyl)-6-methyl pyridazinone],
Poly[3-(2-vinyl)-6-methyl-4,5-pyridazinone],
Poly(cyclopentylmethylethylene), Poly(heptylethylene),
Poly(hexyldecylethylene), Poly(hexylethylene),
Poly(cyclohexylethylene), Poly(cyclopentylethylene),
Poly(cyclopropylethylene), Poly(isopentylethylene),
Poly(isopropylethylene), Poly(3,3-dimethylbutylethylene),
Poly(isohexylethylene), Poly(1,1-dimethylethylene),
Poly(benzylethylene), Poly(N-carbazoylylethylene),
Poly(ferrocenylethylene), Poly(indazol-2-ylethylene),
Poly[dimethylamino(ethoxy)phosphinylethylene],
Poly[dimethylamino(phenoxy)phosphinylethylene],
Poly(4,4-dimethyl-oxazolonylethylene),
Poly(4,4-dimethyl-oxazolonyl-2-propylene),
Poly[(2-methyl-5-pyridyl)ethylene],
Poly[(2-methyl-6-pyridyl)ethylene],
Poly(2,4-dimethyl-1,3,5-triazinylethylene),
Poly(1-naphthylethylene), Poly(2-naphthylethylene),
Poly(phenethylethylene), Poly(phenethylmethylethylene),
Poly(phenylacetylene), Poly(diphenylphosphinylethylene),
Poly(phenylvinylene), Poly(phthalimidoethylene),
Poly(2-pyridylethylene), Poly(4-pyridylethylene),
Poly(N-pyrrolidinylethylene), Poly(m-tolylmethylethylene),
Poly(o-tolylmethylethylene), Poly(p-tolylmethylethylene),
Poly(vinyltrimethylgerm anium), Poly(vinylcyclopropane),
Poly(N-vinyldiphenylamine), Poly(1-vinylene-3-cyclopentylene),
Poly(o-hydroxy-vinylphenylketone), Poly(3-vinyl pyrene),
Poly(2-vinylpyridine), Poly(4-vinylpyridine),
Poly(2-vinyl-5-methylpyridine), Poly(2-vinyl-5-ethylpyridine),
Poly(1-cyano-2-phenylvlnylene), Poly(vinyl
3-trimethylsilylbenzoat), Poly(vinylfuran), Poly(vinylindole),
Poly(2-vinyltetrahydrofuran), Poly(N-vinylphthalimide),
Poly(1-vinylimidazlo), Poly(1-vinyl-2-methyl imidazole),
Poly(5-vinyl-2-methylpyridine), Poly(1-vinylnaphthalene),
Poly(2-vinylnaphthalene), Poly(5-vinyl-2-picoline),
Poly(3-vinylpyrene), Poly(2-vinylpyridine), Poly(4-vinylpyridine),
Poly(2-methyl-5-vinylpyridine), Poly(N-vinylcarbazole),
Poly(1-vinylnaphthalene), Poly(styryl pyridine), Poly(N-vinyl
succinimide), Poly(1,3-divinyl-imidazolid-2-one),
Poly(1-ethyl-3-vinyl-imidazolid-2-one), Poly(p-vinyl benzophenone),
Poly(vinyl N,N-diethyl-carbamate), Poly(vinyl cymantrene),
Poly[vinyl-tris(trimethoxysiloxy)silane], Poly(alpha-chlorovinyl
triethoxysilane), Poly(p-vinylbenzylethylcarbinol),
Poly(p-vinylbenzylmethylcarbinol), Poly(divinylaniline),
Poly(vinylferrocene), Poly(9-vinylanthracene),
Poly(vinylmercaptobenzimidazole), Poly(vinylmercaptobenzoxazole),
Poly(vinylmercaptobenzothiazole), Poly(p-vinyl benzophenone),
Poly(2-vinyl quinoline), Poly(vinylidene cyanide),
Poly(1,2,5-trimethyl-vinylethylnyl-4-piperidinol),
Poly(2-vinyl-1,1-dichlorocyclopropane),
Poly(2-vinyl-2-methyl-4,4,6,6-tetraphenylcyclotrisiloxane),
Poly(N-vinyl-N-methylacetamide), Poly(triethoxysilyl ethylene),
Poly(trimethoxysilyl ethylene), Poly(1-acetoxy-1-cyanoethylene),
Poly(1,1-dichloroethylene), Poly(1,1-dichloro-2-fluoroethylene),
Poly(1,1-dichloro-2,2-difluoroethylene),
Poly(1,2-dichloro-1,2-difluoroethylene),
Poly[(pentafluoroethyl)ethylene],
Poly(tetradecafluoropentylethylene), Poly(hexafluoropropylene),
Poly(2,3,3,3-tetrafluoropropylene), Poly(3,3,3-trifluoropropylene),
Poly[(heptafluoropropyl)ethylene], Poly(2-iodoethylethylene),
Poly(9-iodononylethylene), Poly(3-iodopropylethylene),
Poly[(2-acetoxybenzoyloxy)ethylene],
Poly(4-acetoxybenzoyloxyethylene),
Poly[(1-acetylindazol-3-ylcarbonyloxy)ethylene],
Poly(4-benzoylbutyryloxyethylene), Poly(3-bromobenzoyloxyethylene),
Poly(4-bromobenzoyloxyethylene),
Poly[(t-butoxycarbonylamino)ethylene],
Poly(4-t-butylbenzoyloxyethylene),
Poly(4-butyryloxybenzoyloxyethylene),
Poly(2-chlorobenzoyloxyethylene), Poly(3-chlorobenzoyloxyethylene),
Poly(4-chlorobenzoyloxyethylene), Poly(cyclohexanoyloxyethylene),
Poly(cyclohexylacetoxyethylene),
Poly(4-cyclohexylbutyryloxyethylene),
Poly(cyclopentanoyloxyethylene), Poly(cyclopentyl acetoxyethylene),
Poly(4-ethoxybenzoyloxyethylene), Poly(4-ethylbenzoyloxyethylene),
Poly[(2-ethyl-2,3,3-trimethylbutyryloxy)ethylene],
Poly(trifluoroacetoxyethylene),
Poly(heptafluorobutylryloxyethylene),
Poly[(undecafluorodecanoyloxy)ethylene],
Poly[(nonadecafluorodecanoyloxy)ethylene],
Poly[(undecafluorohexanoyloxy)ethylene],
Poly[(pentadecafluorooctanyloxy)ethylene],
Poly[(pentafluoropropionyloxy)ethylene],
Poly[(heptafluoroisopropoxy)ethylene], Poly(formyloxyethylene),
Poly(isonicotinoyloxyethylene),
Poly(4-isopropylbenzoyloxyethylene),
Poly[(2-isopropyl-2,3-dimethylbutyryloxy)ethylene],
Poly[(2-methoxybenzoyloxy)ethylene],
Poly[(3-methoxybenzoyloxy)ethylene],
Poly[(4-methoxybenzoyloxy)ethylene],
Poly[(2-methylbenzoyloxy)ethylene],
Poly[(3-methylbenzoyloxy)ethylene],
Poly[(4-methylbenzoyloxy)ethylene],
Poly[(1-methylcyclohexanoyloxy)ethylene],
Poly(3,3-dimethyl-3-phenylpropionyloxyethylnene),
Poly[(3-trimethylsilylbenzoyloxy)ethylene],
Poly[(4-trimethylsilylbenzoyloxy)ethylene),
Poly[(2,2-dimethylvaleryloxy)ethylene],
Poly[(2,2,3,3-tetramethylvaleryloxy)ethylene],
Poly[(2,2,3,4-tetramethylvaleryloxy)ethylene],
Poly[(2,2,4,4-tetramethylvaleryloxy)ethylene],
Poly(nicotinoyloxyethylene), Poly(nitratoethylene),
Poly[(3-nitrobenzoyloxy)ethylene],
Poly[(4-nitrobenzoyloxy)ethylene],
Poly[(4-phenylbenzoyloxy)ethylene], Poly(pivaloyloxyethylene),
Poly[(4-propionyloxybenzoyloxy)ethylene],
Poly(propionyloxyethylene), Poly[(4-p-toluoylbutyryloxy)ethylene],
Poly[(1,2-diethoxycarbonyl)ethylene],
Poly[(1,2-dimethoxycarbonyl)ethylene],
Poly[(1,2-dipropoxycarbonyl)ethylene],
Poly(2-bromotetrafluoroethyliminotetrafluoroethylene),
Poly[(biphenyl-4-yl)-ethylene], Poly(2-chloroethoxyethylene),
Poly(hexadecyloxyethylene), Poly(isobutoxyethylene),
Poly(1-methoxycarbonyl-1-phenylethylene),
Poly(9-acrydinylethylene), Poly(4-methoxybenzylethylene),
Poly[(3,6-dibromocarbazoyl)ethylene] Poly(propylene oxide)
Poly(dimethylpentylsilylethylene),
Poly(3,5-dimethylpyrozoylylethylene),
Poly(2-diferrocenyl-furyl-methylene), Poly(ethoxyoxaloyloxymethyl
ethylene), Poly(9-ethyl-3-carbazoyl ethylene),
Poly(fluorenylethylene), Poly(imidazoethylene),
Poly[(8-methoxycarbonyloctyl)ethylene], Poly(1-methoxy-4-naphthyl
ethylene), Poly(2-methyl-5-pyridyl ethylene),
Poly(propoxyoxaloyloxymethyl ethylene),
Poly(1,1-diphenyl-2-vinylcyclopropane),
Poly(p-anthrylphenylethylene),
Poly[1-(N-ethyl-N-(1,4,7,10,13-pentaoxacyclopentadecyl)-carbamoyl)ethylen-
e], Poly(N-carbazolylcarbonyl ethylene), Poly(morpholinocarbonyl
ethylene), Poly(piperidinocarbonyl ethylene),
Poly(N-benztriazolylethylene), Poly[6-(N-carbazoyl)hexyl ethylene],
Poly(2,4-dimethyl-6-triazinylethylene),
Poly(diphenylthiophosphinylideneethylene),
Poly(2-methyl-5-pyridylethylene), Poly(N-thiopyrrolidonylethylene),
Poly(N-1,2,4-triazolylethylene), Poly(phenothiazinyl ethylene),
Poly(L-menthyloxycarbonylaminoethylene),
Poly(N-3-methyl-2-pyrrolidone ethylene), Poly(p-vinyl-1,1-diphenyl
ethylene), Poly(S-vinyl-O-ethylthioacetal formaldehyde),
Poly(N-vinylphthalimide), Poly[N-(4-vinylphenyl)phthalimide],
Poly[2-methyl-5-(4'-vinyl)phenyltetrazole],
Poly[5-phenyl-2-(4'-vinyl)phenyltetrazole],
Poly(N,N-methyl-vinyltoluenesulfonamide), Polyallene,
Poly(1-butene), Poly(1-bromo-1-butene), Poly(1-butyl-1-butene),
Poly(1-t-butyl-1-butene), Poly(1-chloro-1-butene),
Poly(2-chloro-1,4,4-trifluoro-1-butene), Poly(1-decyl-1-butene),
Poly(1-ethyl-butene), Poly(1,4,4-trifluoro-1-butene),
Poly(octafluoro-1-butene), Poly(1-heptyl-1-butene),
Poly(4-p-chlorophenyl-1-butene), Poly(4-p-methoxyphenyl-1-butene),
Poly(4-cyclohexyl-1-butene), Poly(4-phenyl-1-butene),
Poly(2-butene), Poly(isoprene), Poly(3-acetoxyisoprene),
Poly(1-isopropyl-1-butene), Poly[3-(1-cyclohexenyl)isopropenyl
acetate], Poly(4-methoxy-1-butene),
Poly(4-methoxycarbonyl-3-methyl-1-butene),
Poly(1,2-dimethyl-butene), Poly(1-phenyl-butene),
Poly(1-propyl-butene), Poly[(3-methyl)-1-butene)],
Poly[(4-methyl)-1-butene)], Poly[(4-phenyl)-1-butene)],
Poly[(4-cyclohexyl)-1-butene)],
Poly[(4-N,N-diisopropylamino)-1-butene)],
Poly[(3,3-dimethyl)-1-butene)], Poly[(3-phenyl)-1-butene)],
Poly[(4-o-tolyl)-1-butene)], Poly[(4-p-tolyl)-1-butene)],
Poly[(4,4,4-trifluoro)-1-butene)],
Poly[(3-trifluoromethyl)-1-butene)],
Poly[(4-trimethylsilyl)-1-butene], Poly(1,3,3-trimethylbutene),
Poly(1,4-p-methoxyphenylbutene), Poly(1,4-p-chlorophenyl butene),
Poly(1,4-cycl ohexylbutene), Poly(1,4-phenylbutene),
Poly(1,2-diethyl butene), Poly(2,2-dimethylbutene),
Poly(1,3-cyclobutylene), Poly[(1-cyano)-1,3-cyclobutylene],
Poly(N-butenyl carbazole), Poly(1-decene), Poly(1-docosene),
Poly(dodecamethylene), Poly(1,2-chloro-dodecamethylene),
Poly(1-methyl-dodecamethylene), Poly(1-dodecene), Poly(1-nonene),
Poly(1-heptene), Poly(6,6-dimethyl-1-heptene),
Poly(5-methyl-1-heptene), Poly(heptamethylene),
Poly(1,2-dichloro-heptamethylene), Poly[(5-methyl)-1-heptene],
Poly(1-hexadecene), Poly(1-hexene), Poly[(3-methyl)-1-hexene],
Poly[(4-methyl)-1-hexene], Poly[(4,4-dimethyl)-1-hexene],
Poly[(4-ethyl)-1-hexene], Poly[(5-methyl)-1-hexene],
Poly(1,2-cyclohexylene), Poly(1,2-cyclopentylene-alt-ethylene),
Poly(1,3-cyclopentylene-alt-methylene), Poly(isobutene),
Poly(1-octadecene), Poly(octamethylene),
Poly[(1-methyl)octamethylene], Poly(1-octene),
Poly(6,6-dimethyl-4,8-dioxaspiro-1-octene), Poly(1-octadecene),
Poly(1-pentene), Poly(cyclopentene),
Poly(1,3-dione-4-cyclopentene), Poly(3,3-dimethoxycyclopentene),
Poly(1-pentadecene), Poly(5-amino-1-pentene),
Poly(5-cyclohexyl-1-pentene),
Poly[5-(N,N-dimethyl)amino-1-pentene],
Poly[5-(N,N-diisobutyl)amino-1-pentene],
Poly[5-(N,N-dipropyl)amino-1-pentene],
Poly(4,4-dimethyl-1-pentene),
Poly(3-methyl-1-pentene), Poly(3-ethyl-1-pentene),
Poly(4-methyl-1-pentene), Poly(5,5,5-trifluoro-1-pentene),
Poly(4-trifluoromethyl-1-pentene),
Poly(5-trimethylsilyl-1-pentene), Poly(2-methyl-1-pentene),
Poly(5-phenyl-1-pentene), Poly(1,2-cyclopentylene),
Poly(3-chloro-1,2-cyclopentylene), Poly(pentamethylene),
Poly(1,2-dichloropentamethylene), Poly(hexafluoroisobutylene),
Poly(chloroprene), Poly(propene), Poly(3-cyclohexylpropene),
Poly(3-cyclopentylpropene), Poly(hexafluoropropene),
Poly(3-phenylpropane), Poly[3-(2',5'-dimethylphenyl)propene],
Poly(3-(3',4'-dimethylphenyl)propene],
Poly[3-(3',5'-dimethylphenyl)propene], Poly(3-silylpropene),
Poly(3-p-tolylpropene), Poly(3-m-tolylpropene),
Poly(3-o-tolylpropene), Poly(3-trimethylsilylpropene),
Poly(3,3,3-trifluoropropene), Poly(3,3,3-trichloropropene),
Poly(1-chloropropene), Poly(2-chloropropene),
Poly(2,3-dichloropropene), Poly(3-chloro-2-chloromethylpropene),
Poly(ethyl-2-propylene), Poly(1-nitropropylene),
Poly(2-trimethylsilylpropene),
Poly[1-(heptafluoroisopropoxy)methylpropylene],
Poly[(1-heptafluoroisopropoxy)propylene], Poly(N-propenyl
carbazole), Poly(propylidene), Poly(isopropenyltoluene),
Poly(1-tridecene), Poly(1-tetradecene), Poly(vinylcyclobutane),
Poly(vinylcycloheptane), Poly(vinylcyclohexane),
Poly(vinylcyclopentane), Poly(vilnylcyclopropane),
Poly(1-vinylene-3-cyclopentylene), Poly(octamethylene),
Poly(1-methyloctamethylene), Poly(decamethylene),
Poly(1,2-dichloro-decamethylene), Poly(2,5-pyrazinecyclobutylene),
Poly(2,4-diphenyl-2,5-pyrazinecyclobutylene), Poly(1-undecene),
Poly[(R)(-)-3,7-dimethyl-1-octene],
Poly[(S)(+)-5-methyl-1-heptene], Poly[(S)(+)-4-methyl-1-hexene],
Poly[(S)(+)-4-methyl-1-hexyne], Poly[(S)(+)-6-methyl-1-octene],
Poly[(S)(+)-3-methyl-1-pentene], Poly[(R)-4-phenyl-1-hexene],
Poly(dimethyl 2,5-dicarboxylate-1-hexene),
Poly[(S)-5-phenyl-1-heptene], Poly(1-ethyl-1-methyltetramethylene),
Poly(1,1-dimethyltetramethylene), Poly(1,1-dimethyltrimethylene),
Poly(1,1,2-trimethyltrimethylene), Poly(acryloyl chloride),
Poly(allylacrylate), Poly(allyl chloride), Poly(allylbenzene),
Poly(diallyl phthalate), Poly(diallylcyanamide), Poly(acryloyl
pyrriolidone), Poly(allylcyclohexane), Poly(N-allylstearamide),
Poly(allyl chloroacetate), Poly(allyl glycidyl phthalate),
Poly(allylcyclohexane), Poly(allyltriethoxysilane),
Poly(allylurea), Poly(allylbenzene), Poly(acetylene),
Poly(beta-iodophenylacetylene), Poly(diacetylene), Poly(phenyl
acetylene), Poly(3-methyl-1-pentyne), Poly(4-methyl-1-hexyne),
Poly(5-methyl-1-heptyne), Poly(6-methyl-1-octyne),
Poly(3,4-dimethyl-1-pentyne), Poly(2,3-dihydrofuran),
Poly(N,N-dibutylacrylamide), Poly(N-docosylacrylamide),
Poly(N-dodecylacrylamide), Poly(N-formylacrylamide),
Poly(N-hexadecylacrylamide), Poly(N-octadecylacrylamide),
Poly(N-octylacrylamide), Poly(N-phenyl acryl amide),
Poly(N-propylacryl amide), Poly(N-tetradecylacrylamide),
Poly(N-butylacrylamide), Poly(N-sec-butylacrylamide),
Poly(N-t-butylacrylamide), Poly(isodecylacrylamide),
Poly(isohexylacrylamide), Poly(isononylacrylamide),
Poly(isooctylacrylamide),
Poly[N-(1,1-dimethyl-3-oxobutyl)acrylamide],
Poly[1-oxy-(2,2,6,6-tetramethyl-4-piperidyl)acrylamide],
Poly(N,N-dibutylacrylamide), Poly(N,N-diethylacrylamide),
Poly(N,N-diisopropylacrylamide), Poly(N,N-diphenylacrylamide),
Poly[N-(1,1-dimethyl-3-oxobutyl)acrylamide],
Poly[N-(1-methylbutyl)acrylamide],
Poly(N-methyl-N-phenylacrylamide),
Poly(N-phenyl-N-1-naphthylacrylamide),
Poly(N-phenyl-N-2-naphthylacrylamide), Poly(morpholylacrylamide),
Poly(N-octadecylacrylamide), Poly(piperidylacrylamide),
Poly(4-butoxycarbonylphenyl methacrylamide),
Poly(N-t-butylmethacrylamide), Poly(N-benzyl methacrylamide),
Poly(N-phenyl methacrylamide),
Poly[N-(p-chlorophenyl)methacylamide],
Poly[N-(p-methoxyphenyl)methacrylamide],
Poly[N-(p-methylphenyl)methacrylamide],
Poly[N-(p-nitrophenyl)methacrylamide],
Poly[N-(p-stilbenzyl)methacrylamide],
Poly[N-(4'-nitro-p-stibenzyl)methacrylamide],
Poly(N-phenylmethacrylamide), Poly(1-deoxy-D-glucitol
methacrylamide), Poly(4-carboxyphenylmethacrylamide),
Poly(4-ethoxycarbonylphenylmethacrylamide),
Poly(4-methoxycarbonylphenylmethacrylamide), Poly(N-allyl
methacrylamide), Poly[1-(N-carbethoxyphenyl)methacrylamide],
Poly(p-ethoxycarbonyl phenylmethacrylamide), Poly(carbethoxyphenyl
methacrylamide), Poly(N-methyl-N-alpha-methylbenzyl-acrylamide),
Poly(N-propyl-N-alpha-methylbenzyl-acrylamide),
Poly(p-acrylamidomethylamino azobenzene), Poly(allyl acrylate),
Poly(biphenyloxyhexamethylene acrylate), Poly(n-butylacrylate),
Poly(2-nitrobutylacrylate), Poly(sec-butyl acrylate), Poly(t-butyl
acrylate), Poly(p-carboxyphenyl acrylate), Poly(glycidyl acrylate),
Poly(isobutyl acrylate), Poly(isopropyl acrylate), Poly(cresyl
acrylate), Poly(decylacrylate),
Poly(1,1-dihydroperfluoro-decylacrylate), Poly(docosylacrylate),
Poly(dodecylacrylate), Poly(hexadecylacrylate),
Poly(heptylacrylate), Poly(octadecylacrylate), Poly(octylacrylate),
Poly(1,1-dihydroperfluorooctylacrylate), Poly(tetradecylacrylate),
Poly(isopropyl acrylate), Poly(benzyl acrylate), Poly(4-biphenylyl
acrylate), Poly(L-bornyl acrylate), Poly(4-butoxycarbonylphenyl
acrylate), Poly(2-t-butylphenyl acrylate), Poly(4-t-butylphenyl
acrylate), Poly[(1-chlorodifluoromethyl)tetrafluoroethyl acrylate],
Poly[3-chloro-2,2-bis(chloromethyl)propyl acrylate],
Poly(2-chlorophenyl acrylate), Poly(4-chlorophenyl acrylate),
Poly(2,4-dichlorophenyl acrylate), Poly(pentachlorophenyl
acrylate), Poly(4-cyanobenzyl acrylate), Poly(2-cyanobutyl
acrylate), Poly(2-cyanoisobutyl acrylate), Poly(4-cyanobutyl
acrylate), Poly(2-cyanoethyl acrylate), Poly(2-cyanoheptyl
acrylate), Poly(2-cyanohexyl acrylate), Poly(cyanomethyl acrylate),
Poly(2-cyanomethyl acrylate), Poly(5-cyano-3-oxapentyl acrylate),
Poly(4-cyanophenyl acrylate), Poly(2-cyanoisopropyl acrylate),
Poly(4-cyano-3-thiabutyl acrylate), Poly(6-cyano-3-thiahexyl
acrylate), Poly(6-cyano-4-thiahexyl acrylate),
Poly(8-cyano-7-thiaoctyl acrylate), Poly(5-cyano-3-thiapentyl
acrylate), Poly(cyclododecyl acrylate), Poly(cyclohexyl acrylate),
Poly(2-chloroethyl acrylate),
Poly[di(chlorodifluoromethyl)fluoromethyl acrylate],
Poly(2-ethoxycarbonylphenyl acrylate), Poly(3-ethoxycarbonylphenyl
acrylate), Poly(4-ethoxycarbonylphenyl acrylate),
Poly(2-ethoxyethyl acrylate), Poly(3-ethoxypropyl acrylate),
Poly(ethyl acrylate), Poly(2-bromoethyl acrylate),
Poly(2-ethylbutyl acrylate), Poly(2-ethylhexyl acrylate),
Poly(ferrocenylethyl acrylate), Poly(ferrocenylmethyl acrylate),
Poly(1H,1H-heptafluorobutyl acrylate), Poly(heptafluoroisopropyl
acrylate), Poly[5-(heptafluoroisopropoxy)pentyl acrylate],
Poly[11-(heptafluoroisopropoxy)undecyl acrylate],
Poly[2-(heptafluoropropoxy)ethyl acrylate],
Poly[(2-(heptafluorobutoxy)ethyl acrylate],
Poly[2-(1,1,2,2-tetrafluoroethoxy)ethyl acrylate],
Poly(1H,1H,3H-hexafluorobutyl acrylate), Poly(2,2,2-trifluoroethyl
acrylate),
Poly[2,2-difluoro-2-(2-heptafluorotetrahydrofuranyl)ethyl
acrylate], Poly(1H,1H-undecafluorohexyl acrylate),
Poly(fluoromethyl acrylate), Poly(trifluoromethyl acrylate),
Poly(1H,1H-pentadecafluorooctyl acrylate),
Poly(5,5,6,6,7,7,7-heptafluoro-3-oxaheptyl acrylate),
Poly(1H,1H-undecafluoro-4-oxaheptyl acrylate),
Poly(1H,1H-nonafluoro-4-oxaheptyl acrylate),
Poly(7,7,8,8-tetrafluoro-3,6-dioxaoctyl acrylate),
Poly(1H,1H-tridecafluoro-4-oxaoctyl acrylate),
Poly(2,2,3,3,5,5,5-heptafluoro-4-oxapentyl acrylate),
Poly(4,4,5,5-tetrafluoro-3-oxapentyl acrylate),
Poly(5,5,5-trifluoro-3-oxapentyl acrylate),
Poly(1H,1H-nonafluoropentyl acrylate), Poly(nonafluoroisobutyl
acrylate), Poly(1H,1H,5H-octafluoropentyl acrylate),
Poly(heptafluoro-2-propyl acrylate),
Poly[tetrafluoro-3-(heptafluoropropoxy)propyl acrylate],
Poly[(tetrafluoro-3-(pentafluoroethoxy)propyl acrylate],
Poly[tetrafluoro-3-(trifluoromethoxy)propyl acrylate],
Poly(1H,1H-pentafluoropropyl acrylate), Poly(octafluoropentyl
acrylate), Poly(heptyl acrylate), Poly(2-heptyl acrylate),
Poly(hexadecyl acrylate), Poly(hexyl acrylate), Poly(2-ethylhexyl
acrylate), Poly(isobornyl acrylate), Poly(isobutyl acrylate),
Poly(isopropyl acrylate),
Poly(1,2:3,4-di-O-isopropylidene-alpha-D-galactopyranos-6-O-yl
acrylate), Poly(3-methoxybutyl acrylate),
Poly(2-methoxycarbonylphenyl acrylate),
Poly(3-methoxycarbonylphenyl acrylate),
Poly(4-methoxycarbonylphenyl acrylate), Poly(2-methoxyethyl
acrylate), Poly(2-ethoxyethyl acrylate), Poly(4-methoxyphenyl
acrylate), Poly(3-methoxypropyl acrylate),
Poly(3,5-dimethyladamantyl acrylate), Poly(3-dimethylaminophenyl
acrylate), Poly(2-methylbutyl acrylate), Poly(3-methylbutyl
acrylate), Poly(1,3-dimethylbutyl acrylate),
Poly(2-methyl-7-ethyl-4-undecyl acrylate), Poly(2-methylpentyl
acrylate), Poly(menthyl acrylate), Poly(2-naphthyl acrylate),
Poly(nonyl acrylate), Poly(octyl acrylate), Poly(2-octyl acrylate),
Poly(3-pentyl acrylate), Poly(phenethyl acrylate), Poly(phenyl
acrylate), Poly(2,4-dinitrophenyl acrylate),
Poly(2,4,5-trichlorophenyl acrylate), Poly(2,4,6-tribromophenyl
acrylate), Poly(3,4-epoxyhexahydrobenzyl acrylate),
Poly[alpha-(o-ethyl methylphsphonoxy)-methyl acrylate], Poly(propyl
acrylate), Poly(2,3-dibromopropyl acrylate), Poly(tetradecyl
acrylate), Poly(3-thiabutyl acrylate), Poly(4-thiahexyl acrylate),
Poly(5-thiahexyl acrylate, Poly(3-thispentyl acrylate),
Poly(4-thiapentyl acrylate), Poly(m-tolyl acrylate), Poly(o-tolyl
acrylate), Poly(p-tolyl acrylate), Poly(2-ethoxyethyl acrylate),
Poly(3-ethoxypropyl acrylate), Poly(cholesteryl acrylate),
Poly(2-ethyl-n-hexyl acrylate),
Poly(1-oxy-2,2,6,6-tetramethyl-4-piperidyl acrylate),
Poly(1,2,2,6,6-pentamethyl-4-piperidyl acrylate),
Poly(4-phenylazoxyphenyl acrylate), Poly(ethyl cyanoacrylate),
Poly[4-(10,15,20-triphenyl-21H,23H-5-yl)phenyl acrylate],
Poly(1,1,5-trihydroperfluoroamyl acrylate), Poly(tributyltin
acrylate), Poly(beta-ethoxyethyl acrylate),
Poly(3,4-epoxyhexahydrobenzyl acrylate),
Poly(alpha-chloroacrylnitrile), Poly(alpha-fluoroacrylnitrile),
Poly(alpha-methoxy acrylnitrile), Poly(alpha-trifluoromethyl
acrylnitrile), Poly(alpha-ethylacrylonitrile),
Poly(alpha-isopropylacrylonitrile),
Poly(alpha-propylacrylonitrile), Poly(amyl methacrylate),
Poly[1-(3-cyanopropyl)acrylonitrile], Poly(t-butyl methacrylate),
Poly(hexadecyl methacrylate), Poly(methyl methacrylate),
Poly(cyanomethyl methacrylate), Poly(adamantyl methacrylate),
Poly(3,5-dimethyladamantyl methacrylate), Poly(benzyl
methacrylate), Poly(1-alpha-methylbenzyl methacrylate),
Poly(2-bromoethyl methacrylate), Poly(2-t-butylaminoethyl
methacrylate), Poly(butyl methacrylate), Poly(sec-butyl
methacrylate), Poly(tert-butyl methacrylate), Poly(ethylbutyl
metbacrylate), Poly(4-phenylbutyl-1-methacrylate),
Poly(2-phenylethyl-1-methacrylate), Poly(cetyl methacrylate),
Poly(p-cetyloxybenzoyl methacrylate), Poly(2-chloroethyl
methacrylate), Poly(cyanomethyl methacrylate), Poly(2-cyanoethyl
methacrylate), Poly(4-cyanomethylphenyl methacrylate),
Poly(4-cyanophenyl methacrylate), Poly(cyclohexyl methacrylate),
Poly(p-t-butylcyclohexyl methacrylate), Poly(4-t-butylcyclohexyl
methacrylate), Poly(cyclobutyl methacrylate), Poly(cyclobutylmethyl
methacrylate), Poly(cyclododecyl methacrylate),
Poly(2-cyclohexylethyl methacrylate), Poly(cyclohexylmethyl
methacrylate), Poly(cyclopentyl methacrylate), Poly(cyclooctyl
methacrylate), Poly(decyl methacrylate), Poly(n-decyl
methacrylate), Poly(dodecyl methacrylate), Poly(n-decosyl
methacrylate), Poly(diethylaminoethyl methacrylate),
Poly(dimethylaminoethyl methacrylate), Poly(2-ethylhexyl
methacrylate), Poly(ethyl methacrylate), Poly(acetoxyethyl
methacrylate), Poly(2-methoxyethyl methacrylate),
Poly(2-ethylsulfinylethyl methacrylate), Poly(ferrocenylethyl
methacrylate), Poly(ferrocenylmethyl methacrylate),
Poly(N-methyl-N-phenyl-2-aminoethyl methacrylate),
Poly(2-N,N-dimethylcarbamoyloxyethyl methacrylate), Poly(2-acetoxy
methacrylate), Poly(2-bromoethyl methacrylate), Poly(2-chloroethyl
methacrylate), Poly(1H,1H-heptafluorobutyl methacrylate),
Poly(1H,1H,7H-dodecafluoroheptyl methacrylate),
Poly(1H,1H,9H-hexadecafluorononyl methacrylate),
Poly(1H,1H,5H-octafluoropentyl methacrylate),
Poly(1,1,1-trifluoro-2-propyl methacrylate),
Poly(trifluoroisopropyl methacrylate), Poly(hexadecyl
methacrylate), Poly(hexyl methacrylate), Poly(isobornyl
methacrylate), Poly(isobutyl methacrylate), Poly(isopropyl
methacrylate),
Poly(1,2:3,4-di-O-isopropylidene-alpha-D-galactopyranos-6-O-yl
methacrylate), Poly(2,3-O-isopropylidene-DL-glyceritol-1-O-yl
methacrylate), Poly(nonyl methacrylate), Poly(methacrylic acid
anhydride), Poly(4-methoxycarbonylphenyl methacrylate),
Poly(3,5-dimethyladamantyl methacrylate), Poly(dimethylaminoethyl
methacrylate), Poly(2-methylbutyl methacrylate),
Poly(1,3-dimethylbutyl methacrylate), Poly(3,3-dimethylbutyl
methacrylate), Poly(3,3-dimethyl-2-butyl methacrylate),
Poly(3,5,5-trimethylhexyl methacrylate), Poly(trimethylsilyl
methacrylate), Poly[(2-nitratoethyl)methacrylate], Poly(octadecyl
methacrylate), Poly(octyl methacrylate), Poly(n-octadecyl
methacrylate), Poly(3-oxabutyl methacrylate), Poly(pentyl
methacrylate), Poly(neopentyl methacrylate), Poly(phenethyl
methacrylate), Poly(phenyl methacrylate),
Poly(2,6-diisopropylphenyl methacrylate), Poly(2,6-dimethylphenyl
methacrylate), Poly(2,4-dinitrophenyl methacrylate),
Poly(diphenylmethyl methacrylate), Poly(4-t-butylphenyl
methacrylate), Poly(2-t-butylphenyl methacrylate),
Poly(o-ethylphenyl methacrylate), Poly(p-ethylphenyl methacrylate),
Poly(m-chlorophenyl methacrylate), Poly(m-nitrophenyl
methacrylate), Poly(propyl methacrylate), Poly(tetradecyl
methacrylate), Poly(butyl butoxycarbonyl methacrylate),
Poly(tetradecyl methacrylate), Poly(ethylidene dimethacrylate),
Poly(3,3,5-trimethylcyclohexyl methacrylate),
Poly(2-nitro-2-methylpropyl methacrylate), Poly(triethylcarbinyl
methacrylate), Poly(triphenylmethyl methacrylate),
Poly(1,1-diethylpropyl methacrylate), Poly(ethyl glycolate
methacrylate), Poly(3-methylcyclohexyl methacrylate),
Poly(4-methylcyclohexyl metbacrylate), Poly(2-methylcyclohexyl
methacrylate), Poly(1-methylcyclohexyl methacrylate), Poly(bornyl
methacrylate), Poly(tetrahydrofurfuryl methacrylate), Poly(vinyl
methacrylate), Poly(2-chloroethyl methacrylate),
Poly(2-diethylaminoethyl methacrylate), Poly(2-chlorocyclohexyl
methacrylate), Poly(2-aminoethyl methacrylate), Poly(furfuryl
methacrylate), Poly(methylmercaptyl methacrylate),
Poly(2,3-epithiopropyl methacrylate), Poly(ferrocenylethyl
methacrylate), Poly[2-(N,N-dimethylcarbamoyloxy)ethyl
methacrylate], Poly(butyl butoxycarbonyl methacrylate),
Poly(cyclohexyl chloroacrylate), Poly(ethyl chloroacrylate),
Poly(ethyl ethoxycarbonyl methacrylate), Poly(ethyl ethacrylate),
Poly(ethyl fluoromethacrylate), Poly(hexyl hexyloxycarbonyl
methacrylate), Poly(1,1-dihydropentadecafluorooctyl methacrylate),
Poly(heptafluoroisopropyl methacrylate), Poly(heptadecafluorooctyl
methacrylate), Poly(1-hydrotetrafluoroethyl methacrylate),
Poly(1,1-dihydrotetrafluoroisopropyl methacrylate),
Poly(1-hydrohexafluorobutyl methacrylate), Poly(1-nonafluorobutyl
methacrylate), Poly(1,3-dichloropropyl methacrylate),
Poly[2-chloro-1-(chloromethyl)ethyl methacrylate],
Poly(butylmercaptyl methacrylate), Poly(1-phenyl-n-amyl
methacrylate),
Poly[2-heptoxycarbonyl-1-heptoxycarbonylethylene)ethylene],
Poly(2-t-butylphenyl methacrylate), Poly(4-cetyloxycarbonylphenyl
methacrylate), Poly(1-phenylethyl methacrylate),
Poly(p-methoxybenzyl methacrylate), Poly(1-phenylallyl
methacrylate), Poly(p-cyclohexylphenyl methacrylate),
Poly(2-phenylethyl methacrylate), Poly[1-(chlorophenyl)cyclohexyl
methacrylate], Poly(1-phenylcyclohexyl
methacrylate), Poly[2-(phenylsulfonyl)ethyl methacrylate],
Poly(m-cresyl methacrylate), Poly(o-cresyl methacrylate),
Poly(2,3-dibromopropyl methacrylate), Poly(1,2-diphenylethyl
methacrylate), Poly(o-chlorobenzyl methacrylate),
Poly(m-nitrobenzyl methacrylate), Poly(2-diphenyl methacrylate),
Poly(4-diphenyl methacrylate), Poly(alpha-naphthyl methacrylate),
Poly(beta-naphthyl methacrylate), Poly(alpha-naphthyl carbinyl
methacrylate), Poly(2-ethoxyethyl methacrylate), Poly(lauryl
methacrylate), Poly(pentabromophenyl methacrylate),
Poly(o-bromobenzyl methacrylate), Poly(o-chlorodiphenylmethyl
methacrylate), Poly(pentachlorophenyl methacrylate),
Poly(2-diethylamino methacrylate), Poly(2-fluoroethyl
mathacrylate), Poly(hexadecyl methacrylate), Poly(2-ethylbutyl
methacrylate), Poly[4-(4-hexadecyloxy-benzoyloxy)phenyl
methacrylate], Poly(D,L-diisobornyl methacrylate),
Poly(decahydro-beta-naphthyl methacrylate), Poly(5-p-menthyl
methacrylate), Poly(methyl butacrylate), Poly(methyl ethacrylate),
Poly[(2-methylsulfinyl)ethylacrylate], Poly(methylphenylacrylate),
Poly[4-(4-nonyloxy-benzoyloxy)-phenyl methacrylate],
Poly(tetrahydrofurfuryl methacrylate),
Poly[2-(triphenylmethoxy)ethyl methacrylate], Poly(cetyl
methacrylate), Poly(2,3-epoxypropyl methacrylate),
Poly(pentachlorophenyl methacrylate), Poly(pentafluorophenyl
methacrylate), Poly[6-(anisyloxycarbonylphenoxy)hexyl
methacrylate], Poly(ethyl-alpha-bromoacrylate),
Poly[1-(2-N-cyclohexyl-N-methyl-carbamoyloxy)ethyl methacrylate],
Poly[1-(2-N,N-diethylcarbamoyloxy)ethyl methacrylate],
Poly[(2-N,N-diethylcarbamoyloxy)-2-methylethyl methacrylate],
Poly(n-docosyl methacrylate), Poly(2,5-dimethylpyrozolyl
methacrylate), Poly[11-(hexadecyl-dimethylammonio)-undecyl
methacrylate], Poly[2-(4-methyl-1-piperazinylcarbonyloxy)ethyl
methacrylate], Poly[(2-morpholino-carbonyloxy)ethylmethacrylate],
Poly[1-(1-nonyloxy-4-phenoxycarbonyl)phenyl methacrylate],
Poly(1,2,2,6,6-pentamethyl-4-piperidyl methacrylate),
Poly(propionyloxyethyl methacrylate),
Poly[3-(8-oxy]-7,7,9,9-tetramethyl-2,4-dioxo-1,3,8-triazaspiro(4,5)-dec-3-
-yl)propyl methacrylate], Poly(n-stearyl methacrylate),
Poly[4-(1,1,3,3-tetramethylbutyl)phenyl methacrylate], Poly(o-tolyl
methacrylate), Poly(p-tolyl methacrylate),
Poly(2,4,5-trichlorophenyl methacrylate), Poly(n-tridecyl
methacrylate), Poly(triphenylmethyl methacrylate), Poly(trityl
methacrylate), Poly(tetrahydro-4H-pyranyl-2-methacrylate),
Poly(tridecyl methacrylate), Poly[2-(triphenylmethoxy)ethyl
methacrylate],
Poly[2-(4-methyl-1-piperazinylcarbonyloxy)-2-methylethyl
methacrylate],
Poly(p-methoxyphenyl-oxycarbonyl-p-phenoxyhexamethylene
methacrylate), Poly(diphenyl-2-pyridylmethyl methacrylate),
Poly(diphenyl-4-pyridylmethyl methacrylate), Poly(triphenylmethyl
methacrylate),
Poly(hexyleneoxyphenylenecarboxyphenyleneoxymethylene
methacrylate),
Poly[4-(1,1,3,3-tetramethylbutyl)phenylmethacrylate], Poly(glycidyl
methacrylate), Poly(2,2,6,6-tetramethyl-4-piperidinyl
methacrylate), Poly[(2,2-dimethyl-1,3-dioxolane-4-yl)methyl
methacrylate], Poly(alpha-alpha-dimethylbenzyl methacrylate),
Poly(1,1-diphenylethyl methacrylate), Poly(2,3-epithiopropyl
methacrylate), Poly(dicyclopentadienyltitanate dimethacrylate),
Poly(diethylaminoethyl methacrylate), Poly(5-oxo-pyrrolidinylmethyl
methacrylate), Poly(ethyl-alpha-bromoacrylate),
Poly(isopropyl-alpha-bromoacrylate),
Poly(methyl-alpha-bromoacrylate),
Poly(n-pentyl-alpha-bromoacrylate),
Poly(n-propyl-alpha-bromoacrylate), Poly(methyl
alpha-trifluoromethylacrylate), Poly(phenyl alpha-bromoacrylate),
Poly(sec-butyl-alpha-bromoacrylate),
Poly(cyclohexyl-alpha-bromoacrylate),
Poly(methyl-alpha-bromomethacrylate), Poly(butyl chloroacrylate),
Poly(sec-butyl chloroacrylate), Poly(methyl chloroacrylate),
Poly(isobutyl chloroacrylate), Poly(isopropyl chloroacrylate),
Poly(cyclohexyl chloroacrylate), Poly(2-chloroethyl
chloroacrylate),
Poly[1-methoxycarbonyl-1-methoxycarbonylmethylene)ethylene],
Poly(methyl chloroacrylate), Poly(ethyl alpha-chloroacrylate),
Poly(methyl beta-chloroacrylate), Poly(cyclohexyl
alpha-ethoxyacrylate), Poly(methyl fluoroacrylate), Poly(methyl
fluoromethacrylate), Poly(methyl phenylacrylate), Poly(propyl
chloroacrylate), Poly(methyl cyanoacrylate), Poly(ethyl
cyanoacrylate), Poly(butylcyanoacrylate), Poly(sec-butyl
thiolacrylate), Poly(isobutyl thiolacrylate), Poly(ethyl
thioacrylate), Poly(methyl thioacrylate), Poly(butyl thioacrylate),
Poly(isopropyl thiolacrylate), Poly(propyl thiolacrylate),
Poly(phenyl thiomethacrylate), Poly(cyclohexyl thiomethacrylate),
Poly(o-methylphenylthio methacrylate),
Poly(nonyloxy-1,4-phenyleneoxycarbonylphenyl methacrylate),
Poly(4-methyl-2-N,N-dimethyl aminopentyl methacrylate),
Poly[alpha-(4-chlorobenzyl)ethyl acrylate],
Poly[alpha-(4-cyanobenzyl)ethyl acrylate],
Poly[alpha-(4-methoxybenzyl)ethyl acrylate], Poly(alpha-acetoxy
ethyl acrylate), Poly(ethyl alpha-benzylacrylate), Poly(methyl
alpha-benzylacrylate), Poly(methyl alpha-hexylacrylate), Poly(ethyl
alpha-fluoroacrylate), Poly(methyl alpha-fluoroacrylate),
Poly(methyl alpha-isobutylacrylate), Poly(methyl
alpha-isopropylacrylate), Poly(methyl alpha-methoxyacrylate),
Poly(butyl alpha-phenylacrylate), Poly(chloroethyl
alpha-phenylacrylate), Poly(methyl alpha-phenylacrylate),
Poly(propyl alpha-phenylacrylate), Poly(methyl
alpha-propylacrylate), Poly(methyl alpha-sec-butylacrylate),
Poly(methyl alpha-trifluoromethylacrylate), Poly(ethyl
alpha-acetoxyacrylate), Poly(ethyl beta-ethoxyacrylate),
Poly(methacryloyl chloride), Poly(methacryloylactone),
Poly(meethylenebutyrolactone), Poly(acryloylpyrrolidone),
Poly[butyl N-(4-carbethoxyphenyl)itaconamate], Poly[ethyl
N-(4-carbethoxyphenyl)itaconamate], Poly[methyl
N-(4-carbethoxyphenyl)itaconamate], Poly[propyl
N-(4-carbethoxyphenyl)itaconamate], Poly[ethyl
N-(4-chlorophenyl)itaconamate], Poly[methyl
N-(4-chlorophenyl)itaconamate], Poly[propyl
N-(4-chlorophenyl)itaconamate], Poly[butyl
N-(4-methoxyphenyl)itaconamate], Poly[ethyl
N-(4-methoxyphenyl)itaconamate], Poly[methyl
N-(4-methoxyphenyl)itaconamate], Poly[propyl
N-(4-methoxyphenyl)itaconamate], Poly[butyl
N-(4-methylphenyl)itaconamate], Poly[ethyl
N-(4-methylphenyl)itaconamate], Poly[methyl
N-(4-methylphenyl)itaconamate], Poly[propyl
N-(4-methylphenyl)itaconamate], Poly[butyl N-phenyl itaconamate],
Poly[ethyl N-phenyl itaconamate], Poly[methyl N-phenyl
itaconamate], Poly[propyl N-phenyl itaconamate], Poly(diamyl
itaconate), Poly(dibutyl itaconate), Poly(diethyl itaconate),
Poly(dioctyl itaconate), Poly(dipropyl itaconate), Polystyrene,
Poly[(p-t-butyl)-styrene], Poly[(o-fluoro)-styrene],
Poly[(p-fluoro)-styrene], Poly[(alpha-methyl)-styrene],
Poly[(alpha-methyl)(p-methyl)-styrene], Poly[(m-methyl)-styrene],
Poly[(o-methyl)-styrene], Poly[(o-methyl)(p-fluoro)-styrene],
Poly[(p-methyl)-styrene], Poly(trimethylsilylstyrene),
Poly(beta-nitrostyrene), Poly(4-acetylstyrene),
Poly(4-acetoxystyrene), Poly(4-p-anisoylstyrene),
Poly(4-benzoylstyrene), Poly[(2-benzoyloxymethyl)styrene],
Poly[(3-(4-biphenylyl)styrene], Poly[(4-(4-biphenylyl)styrene],
Poly(5-bromo-2-butoxystyrene), Poly(5-bromo-2-ethoxystyrene),
Poly(5-bromo-2-isopentyloxystyrene),
Poly(5-bromo-2-isopropoxystyrene), Poly(4-bromostyrene),
Poly(2-butoxycarbonylstyrene), Poly(4-butoxycarbonylstyrene),
Poly(4-[(2-butoxyethoxy)methyl]styrene),
Poly(2-butoxymethylstyrene), Poly(4-butoxymethylstyrene),
Poly[4-(sec-butoxymethyl)styrene], Poly(4-butoxystyrene),
Poly(5-t-butyl-2-methylstyrene), Poly(4-butylstyrene),
Poly(4-sec-butylstyrene), Poly(4-t-butylstyrene),
Poly(4-butyrylstyrene), Poly(4-chloro-3-fluorostyrene),
Poly(4-chloro-2-methylstyrene), Poly(4-chloro-3-methylstyrene),
Poly(2-chlorostyrene), Poly(3-chlorostyrene),
Poly(4-chlorostyrene), Poly(2,4-dichlorostyrene),
Poly(2,5-dichlorostyrene), Poly(2,6-dichlorostyrene),
Poly(3,4-dichlorostyrene), Poly(2-bromo-4-trifluoromethylstyrene),
Poly(4-cyanostyrene), Poly(4-decylstyrene), Poly(4-dodecylstyrene),
Poly(2-ethoxycarbonylstyrene), Poly(4-ethoxycarbonylstyrene),
Poly[4-(2-ethoxymethyl)styrene], Poly(2-ethoxymethylstyrene),
Poly(4-ethoxystyrene),
Poly[4-(2-diethylaminoethoxycarbonyl)styrene],
Poly(4-diethylcarbamoylstyrene),
Poly[4-(1-ethylhexyloxymethyl)styrene], Poly(2-ethylstyrene),
Poly(3-ethylstyrene), Poly(4-ethyl styrene),
Poly[4-(pentadecafluoroheptyl)styrene],
Poly(2-fluoro-5-methylstyrene), Poly(4-fluorostyrene),
Poly(3-fluorostyrene), Poly(4-fluoro-2-trifluoromethyl styrene),
Poly(p-fluoromethyl styrene), Poly(2,5-difluorostyrene),
Poly(2,3,4,5,6,-pentafluorostyrene), Poly(perfluorostyrene),
Poly(alpha,beta,beta-trifluorostyrene), Poly(4-hexadecylstyrene),
Poly(4-hexanoylstyrene), Poly(2-hexyloxycarbonylstyrene),
Poly(4-hexyloxycarbonylstyrene), Poly(4-hexyloxymethylstyrene),
Poly(4-hexylstyrene), Poly(4-iodostyrene),
Poly(2-isobutoxycarbonylstyrene), Poly(4-isobutoxycarbonylstyrene),
Poly(2-isopentyloxycarbonylstyrene),
Poly(2-isopentyloxymethylstyrene), Poly(4-isopentyloxystyrene),
Poly(2-isopropoxycarbonylstyrene),
Poly(4-isopropoxycarbonylstyrene), Poly(2-isopropoxymethylstyrene),
Poly(4-isopropylstyrene), Poly(4-isopropyl-alpha-methylstyrene),
Poly(4-trimethylsilyl-alpha-methylstyrene),
Poly(2,4-diisopropylstyrene), Poly(2,5-diisopropylstyrene),
Poly(beta-methylstyrene), Poly(2-methoxymethylstyrene),
Poly(2-methoxycarbonylstyrene), Poly(4-methoxycarbonylstyrene),
Poly(4-methoxymethylstyrene), Poly(4-methoxy-2-methylstyrene),
Poly(2-methoxystyrene), Poly(4-methoxystyrene),
Poly(4-N,N-dimethylamino styrene),
Poly(2-methylaminocarbonylstyrene),
Poly(2-dimethylaminocarbonylstyrene),
Poly(4-dimethylaminocarbonylstyrene),
Poly[2-(2-dimethylaminoethoxycarbonyl)styrene],
Poly[4-(2-dimethylaminoethoxycarbonyl)styrene],
Poly(2-methylstyrene), Poly(3-methylstyrene),
Poly(4-methylstyrene), Poly(4-methoxystyrene),
Poly(2,4-dimethylstyrene), Poly(2,5-dimethylstyrene),
Poly(3,4-dimethylstyrene), Poly(3,5-dimethylstyrene),
Poly(2,4,5-trimethylstyrene), Poly(2,4,6-trimethylstyrene),
Poly(3-[bis(trimethylsiloxy)boryl]styrene),
Poly(4-[bis(trimethylsiloxy)boryl]styrene),
Poly(4-morpholinocarbonylstyrene),
Poly[4-(3-morpholinopropionyl)styrene], Poly(4-nonadecylstyrene),
Poly(4-nonylstyrene), Poly(4-octadecylstyrene),
Poly(4-octanoylstyrene), Poly[4-(octyloxymethyl)styrene],
Poly(2-octyloxystyrene), Poly(4-octyloxystyrene),
Poly(2-pentyloxycarbonylstyrene), Poly(2-pentyloxymethylstyrene),
Poly(2-phenethyloxymethylstyrene), Poly(2-phenoxycarbonylstyrene),
Poly(4-phenoxystyrene), Poly(4-phenylacetylstyrene),
Poly(2-phenylaminocarbonylstyrene), Poly(4-phenylstyrene),
Poly(4-piperidinocarbonylstyrene),
Poly[4-(3-piperidinopropionyl)styrene], Poly(4-propionylstyrene),
Poly(2-propoxycarbonylstyrene), Poly(4-propoxycarbonylstyrene),
Poly(2-propoxymethylstyrene), Poly(4-propoxymethylstyrene),
Poly(4-propoxystyrene), Poly(4-propoxysulfonylstyrene),
Poly(4-tetradecylstyrene), Poly(4-p-toluoylstyrene),
Poly(4-trimethylsilylstyrene),
Poly[2-(2-thio-3-methylpentyl)styrene],
Poly[9-(2-methylbutyl)-2-vinyl carbazole],
Poly[9-(2-methylbutyl)-3-vinyl carbazole], Poly(3-sec-butyl-9-vinyl
carbazole), Poly[p-(p-tolylsulfinyl)styrene],
Poly(4-valerylstyrene), Poly[(4-t-butyl-dimethylsilyl)oxy styrene],
Poly(4-isopropyl-2-methyl styrene),
Poly[1-(4-formylphenyl)ethylene], Poly(alpha-methoxystyrene),
Poly(alpha-methylstyrene), Poly(p-octylamine sulfonate styrene),
Poly(m-divinylbenzene), Poly(p-divinylbenzene), Polybutadiene
(1,4-addition), Polybutadiene (1,2-addition),
(2-t-butyl)-cis-1,4-poly-1,3-butadiene,
(2-chloro)-trans-1,4-poly-1,3-butadiene,
(2-chloro)-cis-1,4-poly-1,3-butadiene,
(1-cyano)-trans-1,4-poly-1,3-butadiene,
(1-methoxy)-trans-1,4-poly-1,3-butadiene,
(2,3-dichloro)-trans-1,4-poly-1,3-butadiene,
(2,3-dimethyl)-trans-1,4-poly-1,3-butadiene,
(2,3-dimethyl)-cis-1,4-poly-1,3-butadiene,
(2-methyl)-cis-1,4-poly-1,3-butadiene,
(2-methyl)-trans-1,4-poly-1,3-butadiene,
(2-methyl-3-chloro)-trans-1,4-poly-1,3-butadiene,
(2-methylacetoxy)-trans-1,4-poly-1,3-butadiene,
(2-propyl)-trans-1,4-poly-1,3-butadiene,
Poly(2-decyl-1,3-butadiene), Poly(2-heptyl-1,3-butadiene),
Poly(2-isopropyl-1,3-butadiene), Poly(2-t-butyl-1,3-butadiene),
[1,4-(4,4'-diphenyleneglutarate)]-1,4-poly-1,3-butadiene,
Poly(2-chloromethyl-1,3-butadiene),
Poly(ethyl-1-carboxylate-1,3-butadiene),
Poly(1-diethylamino-1,3-butadiene), Poly(diethyl
1,4-carboxylate-1,3-butadiene), Poly(1-acetoxy-1,3-butadiene),
Poly(1-ethoxy-1,3-butadiene),
Poly(2-phthalidomethyl-1,3-butadiene),
Poly(2,3-bis(diethylphosphono-1,3-butadiene),
Poly(hexafluoro-1,3-butadiene), Poly(2-fluoro-1,3-butadiene),
Poly(1-phthalimido-1,3-butadiene),
Poly(1,4-poly-1,3-cyclohexylene), 1,12-poly-1,11-dodecadiyne,
1,2-poly-1,3-pentadiene, (4-methyl)-1,2-poly-1,4-pentadiene,
Poly(perfluoro-1,4-pentadiene), Poly(1-ferrocenyl-1,3-butadiene),
Poly(perfluorobutadiene), Poly(1-phenylbutadiene),
Poly(spiro-2,4-hepta-4,6-diene), Poly(1,1,2-trichlorobutadiene),
Poly(1,3-pentadiene), 1,4-poly-1,3-heptadiene,
(6-methyl)-trans-1,4-poly-1,3-heptadiene,
(5-methyl)-trans-1,4-poly-1,3-heptadiene,
(3,5-dimethyl)-1,4-poly-1,3-heptadiene,
(6-phenyl)-1,4-poly-1,3-heptadiene, 1,4-poly-trans-1,3-hexadiene,
(5-methyl)-trans-1,4-poly-1,3-hexadiene,
(5-phenyl)-trans-1,4-poly-1,3-hexadiene,
trans-2,5-poly-2,4-hexadiene,
(2,5-dimethyl)-trans-2,5-poly-2,4-hexadiene, Poly(1,5-hexadiene),
1,4-poly-1,3-octadiene, 1,4-poly-chloroprene, 1,4-poly-isoprene,
Poly(hexatriene), Poly(trichlorohexatriene),
2,5-poly-2,4-hexadienoic acid, diisopropyl ester,
2,5-poly-2,4-hexadienoic acid, butyl ester,
2,5-poly-2,4-hexadienoic acid, ethyl ester,
2,5-poly-2,4-hexadienoic acid, isoamyl ester,
2,5-poly-2,4-hexadienoic acid, isobutyl ester,
2,5-poly-2,4-hexadienoicacid, isopropyl ester,
2,5-poly-2,4-hexadienoic acid, methyl ester,
2,5-poly-2,4-hexadiyne,
[1,6-di(N-carbazoyl))-2,5-poly-2,4-hexadiyne,
1,9-poly-1,8-nonadiyne, 1,4-poly-1,3-octadene,
1,2-poly-1,3-pentadiene, (4-methyl)-1,2-poly-1,3-pentadiene,
1,4-poly-1,3-pentadiene, (2-methyl)-1,4-poly-1,3-pentadiene,
2,5-poly-5-phenyl-2,4-pentadienoic acid, butyl ester,
2,5-poly-5-phenyl-2,4-pentadienoic acid, methyl ester,
Poly(4-trans-4-ethoxy-2,4-pentadienoate),
Poly(trans-4-ethoxy-2,4-pentadienonitrile),
1,24-poly-1,11,13,23-tetracisatetrayne, Poly(3-hydroxybutyric
acid), Poly(10-hydroxycapric acid),
Poly(3-hydroxy-3-trichloromethyl-propionic acid),
Poly(2-hydroxyacetic acid), Poly(dimethyl-2-hydroxyacetic acid),
Poly(diethyl-2-hydroxyacetic acid), Poly(isopropyl-2-hydroxyacetic
acid), Poly(3-hydroxy-3-butenoic acid), Poly(6-hydroxy-carproic
acid), Poly(5-hydroxy-2-(1,3-dioxane)-carprylic acid],
Poly(7-hydroxynanthic acid), Poly[(4-methyl)-7-hydroxynanthic
acid], Poly[4-hydroxymethylene-2-(1,3-dioxane)-carprylic acid],
Poly(5-hydroxy-3-oxavaleric acid),
Poly(2,3,4-trimethoxy-5-hydroxyvaleric acid),
Poly(2-hydroxypropionic acid), Poly(3-hydroxypropionic acid),
Poly(2,2-bischloromethyl-3-hydroxypropionic acid),
Poly(3-chloromethyl-3-hydroxypropionic acid),
Poly(2,2-butyl-3-hydroxypropionic acid),
Poly(3-dichloromethyl-3-hydroxypropionic acid),
Poly(2,2-diethyl-3-hydroxypropionic acid),
Poly(2,2-dimethyl-3-hydroxypropionic acid),
Poly(3-ethyl-3-hydroxypropionic acid),
Poly(2-ethyl-2-methyl-3-hydroxypropionic acid),
Poly(2-ethyl-2-methyl-1,1-dichloro-3-hydroxypropionic acid),
Poly(3-isopropyl-3-hydroxypropionic acid),
Poly(2-methyl-3-hydroxypropionic acid),
Poly(3-methyl-3-hydroxypropionic acid),
Poly(2-methyl-2-propyl-3-hydroxypropionic acid),
Poly(3-trichloromethyl-3-hydroxypropionic acid),
Poly(carbonoxide-alt-ethylene),
Poly(oxycarbonyl-1,5-dimethylpentamethylene),
Poly(oxycarbonylethylidene), Poly(oxycarbonylisobutylidene),
Poly(oxycarbonylisopentylidene), Poly(oxycarbonylpentamethylene),
Poly(oxycrabonyl-3-methylhexamethylene),
Poly(oxycarbonyl-2-methylpentamethylene),
Poly(oxycarbonyl-3-methylpentamethylene),
Poly(oxycarbonyl-4-methylpentamethylene),
Poly(oxycarbonyl-1,2,3-trimethyloxytetramethylene),
Poly(2-mercaptocarproic acid), Poly(4-methyl-2-mercaptocarproic
acid), Poly(2-mercaptoacetic acid), Poly(2-methyl-2-mercaptoacetic
acid), Poly(3-mercaptopropionoic acid),
Poly(2-phthalimido-3-mercaptopropionoic acid),
Poly[2-(p-toluenesulfonamido)-3-mercaptopropionic acid],
Poly(thiodipropionic anhydride), Poly(ethyl alpha-cyanocinnamate),
Poly(cinnamonitrile), Poly(alpha-cyanocinnamonitrile),
Poly(N-methyl citraconimide), Poly(methyl alpha-acetyl crotonate),
Poly(ethyl alpha-carbethoxy crotonate), Poly(ethyl
alpha-chlorocrotonate), Poly(ethyl alpha-cyanocrotonate),
Poly(methyl alpha-methoxycrotonate), Poly(methyl
alpha-methylcrotonate), Poly(ethyl crotonate), Poly(diethyl
fumarate), Poly(vinyl acetalacetate), Poly(vinyl chloroacetate),
Poly(vinyl dichloroacetate), Poly(vinyl trichloroacetate),
Poly(trifluorovinyl acetate), Poly(propenyl acetate),
Poly(2-chloropropenyl acetate), Poly(2-methylpropenyl acetate),
Poly(vinyl chloroacetate), Poly(vinyl benzoate),
Poly(p-t-butylvinyl benzoate), Poly(vinyl 4-chlorobenzoate),
Poly(vinyl 3-trimethylsilylbenzoate), Poly(vinyl
4-trimethylsilylbenzoate), Poly(p-acryloyloxyphenyl benzoate),
Poly(vinyl butyrate), Poly(vinyl 1,2-phenylbutyrate), Poly(vinyl
caproate), Poly(vinyl cinnamate), Poly(vinyl decanoate), Poly(vinyl
dodecanoate), Poly(vinylformate), Poly(methyl allyl fumarate),
Poly(vinyl hexanoate), Poly(vinyl 2-ethylhexanoate), Poly(vinyl
hexadeconoate), Poly(vinyl isobutyrate), Poly(vinyl isocaproate),
Poly(vinyl laurate), Poly(vinyl myristate), Poly(vinyl octanoate),
Poly(methyl allyl oxalate), Poly(octyl allyl oxalate),
Poly(1-vinyl-palmitate), Poly(t-butyl-4-vinyl perbenzoate),
Poly(vinyl propionoate), Poly(vinyl pivalate), Poly(vinyl
stearate), Poly(2-chloropropenyl acetate), Poly(vinyl
hendecanoate), Poly(vinyl thioacetate), Poly(vinylhydroquinone
dibenzoate), Poly(vinyl isocyanate), Poly(N-vinyl-ethyl carbamate),
Poly(N-vinyl-t-butyl carbamate), Poly(N,N-diethyl vinyl carbamate),
Poly(2-chloro-propenyl acetate), Poly(vinylhydroquinone
dibenzoate), Poly(ethyl trans-4-ethoxy-2,4-pentadienoate),
Poly(triallyl citrate), Poly(vinyl 12-ketostearate), Poly(vinyl
2-ethylhexanoate), Poly(vinylene carbonate), Poly(divinyl adipate),
Poly(vinyl hexadecanoate), Poly(vinyl pelargonate), Poly(vinyl
thioisocyanate), Poly(vinyl valerate),
Poly(diallyl-beta-cyanoethylisocyanurate), Poly(diallylcyanamide),
Poly(triallyl citrate), Poly(triallyl cyanurate), Poly(triallyl
isocyanurate), Poly[3-(1-cyclohexenyl)isopropenyl acetate),
Poly(isopropenyl acetate), Poly(isopropenylisocyanate), Poly(vinyl
diethyl phosphate), Poly(allyl acetate), Poly(vinyl
phenylisocyanate), Poly(benzylvinylether), Poly(butylvinylether),
Poly(2-methylbutylvinylether), Poly(sec-butylvinylether),
Poly(1-methyl-sec-butylvinylether), Poly(t-butylvinylether),
Poly(butylthioethylene), Poly(1-butoxy-2-chloroethylene),cis,
Poly(1-butoxy-2-chloroethylene),trans,
Poly(1-chloro-2-isobutoxyethylene),trans,
Poly(1-isobutoxy-2-methylethylene),trans, Poly(ethylvinyl ether),
Poly(2-chloroethylvinyl ether), Poly(2-bromoethylvinyl ether),
Poly(vinylbutyl sulfonate), Poly(2-methoxyethylvinyl ether),
Poly(2,2,2-trifluoroethylvinyl ether), Poly(isobutylvinylether),
Poly(isopropylvinylether), Poly(methylvinylether), Poly(octylvinyl
ether), Poly(alpha-methylvinylether), Poly(n-pentylvinylether),
Poly(propylvinylether), Poly(1-methylpropylvinylether),
Poly(decylvinyl ether), Poly(dodecylvinyl ether),
Poly(isobutylpropenyl ether), Poly(cyclohexyloxyethylene),
Poly(hexadecyloxyethylene), Poly(octadecyloxyethylene),
Poly(1-bornyloxyethylene), Poly(1-cholesteryloxyethylene),
Poly(1,2-5,6-diisopropylidene-alpha-D-glucofuranosyl-3-oxyethylene),
Poly(1-menthyloxyethylene), Poly(1-alpha-methylbenzyloxyethylene),
Poly[3-beta-(styryloxy)methane], Poly(2-phenylvinyl 2-methylbutyl
ether), Poly(2-phenylvinyl 3-methylpentyl ether),
Poly[(2-ethylhexyloxy)ethylene], Poly(ethylthioethylene),
Poly(dodecafluorobutoxyethylene),
Poly(2,2,2-trifluoroethoxytrifluoroethylene),
Poly[1,1-bis(trifluoromethoxy)difluoroethylene],
Poly(1,1-difluoro-2-trifluoromethoxymethylene),
Poly(1,2-difluoro-1-trifluoromethoxymethylene),
Poly(hexafluoromethoxyethylene),
Poly[(heptafluoro-2-propoxy)ethylene], Poly(hexyloxyethylene),
Poly(isobutoxyethylene), Poly(isopropenyl methyl ether),
Poly(isopropoxyethylene), Poly(methoxyethylene),
Poly(2-methoxypropylene), Poly(2,2-dimethylbutoxyethylene),
Poly(methylthioethylene), Poly(neopentyloxyethylene),
Poly(octyloxyethylene), Poly(pentyloxyethylene),
Poly(propoxyethylene), Poly(1-acetyl-1-fluoroethylene),
Poly(4-bromo-3-methoxybenzoylethylene),
Poly(4-t-butylbenzoylethylene), Poly(4-chlorobenzoylethylene),
Poly(4-ethylbenzoylethylene), Poly(4-isopropylbenzoylethylene),
Poly(4-methoxybenzoylethylene), Poly(3,4-dimethylbenzoylethylene),
Poly(4-propylbenzoylethylene), Poly(p-toluoylethylene), Poly(vinyl
isobutyl sulfide), Poly(vinyl methyl sulfide), Poly(vinyl phenyl
sulfide), Poly(vinyl ethyl sulfoxide), Poly(vinyl ethyl sulfide),
Poly(t-butyl vinyl ketone), Poly(isopropenyl methyl ketone),
Poly(methyl vinyl ketone), Poly(phenyl vinyl ketone),
Poly(2-methylbutyl vinyl ketone), Poly(3-methylpentyl vinyl
ketone), Poly(isopropenylisocyanate), Poly(vinyl chloromethyl
ketone), Poly(vinyl 2-chlorocyclohexyl ketone), Poly(vinyl
4-chlorocyclohexyl ketone), Poly(2-chloroacetaldehyde),
Poly(2,2-dichloroacetaldehyde), Poly(2,2,2-trichloroacetaldehyde),
Poly(2-butene oxide), Poly(2-methyl-2-butene oxide), Poly(butadiene
oxide), Poly(butyraldehyde), Poly(crotonaldehyde),
Poly(valeraldehyde), Poly(1,3-cyclobutyleneoxymethylene oxide),
Poly[(2,2,4,4-tetramethyl)-1,3-cyclobutyleneoxymethylene oxide],
Poly(decamethylene oxide), Poly(dodecamethylene oxide),
Poly(ethylene trimethylene oxide),
Poly(1,1-bischloromethyl-ethylene oxide),
Poly(bromomethyl-ethyleneoxide), Poly(t-butyl-ethyleneoxide),
Poly(chloromethyl-ethylene oxide), Poly(1,2-dichloromethyl-ethylene
oxide), Poly(1-fluoroethylene oxide),
Poly(isopropyl-ethyleneoxide), Poly(neopentyl-ethyleneoxide),
Poly(tetrafluoro-ethylene oxide), Poly(tetramethyl-ethylene oxide),
Poly(ethyleneoxymethylene oxide), Poly(heptaldehyde),
Poly(hexamethyleneoxide), Poly(hexamethyleneoxymethylene oxide),
Poly(isobutyleneoxide), Poly(isobutyraldehyde),
Poly(isophthalaldehyde), Poly(isopropylideneoxide),
Poly(isovaleraldehyde), Poly(methyleneoxypentamethylene oxide),
Poly(methyleneoxytetramethyleneoxide),
Poly(methyleneoxynonamethylene oxide),
Poly(methyleneoxyoctamethylene oxide),
Poly(methyleneoxytetradecamethyleneoxide), Poly(nonaldehyde),
Poly(decamethylene oxide), Poly(nonamethyleneoxide),
Poly(octamethyleneoxide), Poly(trimethylene oxide),
Poly(3,3-bisazidomethyl-trimethyleneoxide),
Poly(3,3-bischloromethyl-trimethyleneoxide),
Poly(3,3-bisbromomethyl-trimethyleneoxide),
Poly(3,3-bisethoxymethyl-trimethylene oxide),
Poly(3,3-bisiodomethyl-trimethylene oxide),
Poly(2,2-bistrifluoromethyl-trimethylene oxide),
Poly(3,3-dimethyl-trimethylene oxide),
Poly(3,3-diethyl-trimethylene oxide),
Poly(3-ethyl-3-methyl-trimethylene oxide), Poly(caprylaldehyde),
Poly(propionaldehyde), Poly(3-methoxycarbonyl-propionaldehyde),
Poly(3-cyano-propionaldehyde), Poly(propylene oxide),
Poly(2-chloromethyl-propylene oxide),
Poly[3-(1-naphthoxy)-propylene oxide],
Poly[3-(2-naphthoxy)-propylene oxide], Poly(3-phenoxy-propylene
oxide), Poly[3-(o-chloro-phenoxy)propylene oxide],
Poly[3-(p-chloro-phenoxy)propylene oxide],
Poly[3-(dimethyl-phenoxy)propylene oxide],
Poly[3-(o-isopropyl-phenoxy)propylene oxide],
Poly[3-(p-methoxy-phenoxy)propylene oxide],
Poly[3-(m-methyl-phenoxy)propylene oxide],
Poly[3-(o-methyl-phenoxy)propylene oxide],
Poly[3-(o-phenyl-phenoxy)propylene oxide],
Poly[3-(2,4,6-trichloro-phenoxy)propylene oxide],
Poly(3,3,3-trifluoro-propylene oxide), Poly(tetramethylene oxide),
Poly(cyclopropylidenedimethylene oxide), Poly(styrene oxide),
Poly(allyloxymethylethylene oxide), Poly(butoxymethylethylene
oxide), Poly(butylethyleneoxide), Poly(4-chlorobutylethyleneoxide),
Poly(2-chloroethylethyleneoxide),
Poly(2-cyanoethyloxymethyleneoxide), Poly(t-butylethylene oxide),
Poly(2,2-bischloromethyltrimethylene oxide), Poly(decylethylene
oxide), Poly(ethoxymethylethyleneoxide),
Poly(2-ethyl-2-chloromethyltrimethylene oxide),
Poly(ethylethyleneoxide),
Poly[1-(2,2,3,3,-tetrafluorocyclobutyl)ethylene oxide),
Poly(octafluorotetramethylene oxide),
Poly[1-(heptafluoro-2-propoxymethyl)ethylene],
Poly(hexylethyleneoxide), Poly[(hexyloxymethyl)ethylene oxide],
Poly(methyleneoxy-2,2,3,3,4,4-hexafluoro-pentamethylene oxide),
Poly(methyleneoxy-2,2,3,3,4,4,5,5-octafluoro-hexamethylene oxide),
Poly(1,1-dimethylethylene oxide), Poly(1,2-dimethylethylene oxide),
Poly(1-methyltrimethylene oxide), Poly(2-methyltrimethylene oxide),
Poly(methyleneoxytetramethylene oxide), Poly(octadecylethylene
oxide), Poly(trifluoropropylene oxide),
Poly(1,1-difluoroethyliminotetrafluoroethylene oxide),
Poly(trifluoromethyliminotetrafluoro oxide), Poly(1,2-hexylene
oxide), Poly(ethylenethioethylene oxide), Poly(difluoromethylene
sulfide), Poly(methylenethiotetramethylene sulfide),
Poly(1-ethylethylene sulfide), Poly(ethylmethylethylene sulfide),
Poly(2-ethyl-2-methyltrimethylene sulfide),
Poly(ethylene.trimethylene.sulfide), Poly(t-butylethylene sulfide),
Poly(isopropylethylene sulfide), Poly(hexamethylene sulfide),
Poly(1,2-cyclohexylene sulfide), Poly(1,3-cyclohexylene sulfide),
Poly(1,2-cyclohexylene sulfone), Poly(1,3-cyclohexylene sulfone),
Poly(hexamethylene sulfone), Poly(pentamethylene sulfide),
Poly(pentamethylene sulfone), Poly(propylene sulfide),
Poly(isobutylene sulfide), Poly(isopropylidene sulfide),
Poly(2-butene sulfide), Poly(hexamethylenethiopentamethylene
sulfide), Poly(hexamethylenethiotetramethylene sulfide),
Poly(trimethylene sulfide), Poly(1-methyltrimethylene sulfide),
Poly(3-methyl-6-oxo-hexamethylene sulfide),
Poly(1-methyl-3-oxo-trimethylene sulfide), Poly(6-oxohexamethylene
sulfide), Poly(2,2-dimethyl-trimethylene sulfide),
Poly(trimethylene sulfone), Poly(2,2-dimethyltrimethylene sulfone),
Poly(2,2-diethyltrimethylene sulfone),
Poly(2,2-dipentyltrimethylene sulfone), Poly(tetramethylene
sulfide), Poly(tetramethylene sulfone),
Poly(ethylenethiohexamethylene sulfide),
Poly(ethylenethiotetramethylene sulfide),
Poly(pentamethylenethiotetramethylene sulfide), Poly(tetramethylene
sulfide), Poly(decamethylene sulfide), Poly(p-tolyl vinyl
sulfoxide), Poly(decamethylene disulfide),
Poly(heptamethylenedisulfide), Poly(hexamethylenedisulfide),
Poly(nonamethylene disulfide), Poly(octamethylene disulfide),
Poly(pentamethylene disulfide),
Poly(octamethylenedithiotetramethylene disulfide),
Poly(oxyethylenedithioethylene),
Poly(oxyethylenetetrathioethylene), Poly(dimethylketene),
Poly(thiocarbonyl-3-methylpentamethylene),
Poly(thiocarbonyl-2-methylpentamethylene),
Poly(thiocarbonyl-1-methylethylene),
Poly(thiocarbonyl-1-p-methoxybenzenesulfonylethylene),
Poly(thiocarbonyl-1-tosylaminoethylene),
Poly(thiocarbonyl-1-p-chlorobenzenesulfoamidoethylene),
Poly(butylethyleneamine), Poly(ethylethylene amine),
Poly(isobutylethylene amine), Poly(1,2-diethylethylene amine),
Poly(1-butyl-2-ethylethylene amine),
Poly(2-ethyl-1-pentylethylene), Poly(N-formyl-isopropylethylene),
Poly(isopropylethylene amine), Poly(N-formylpropylene amine),
Poly(ethylene trimethylene amine), Poly(N-acetyl-ethylene amine),
Poly(N-benzoyl-ethylene amine), Poly[N-(p-chloro-benzoyl)-ethylene
amine], Poly(N-butyryl-ethyleneamine),
Poly[N-[4-(4-methylthiophenoxy)-butyryl]-ethyleneamine],
Poly(N-cyclohexanecarbonyl-ethylene amine),
Poly(N-dodecanoyl-ethylene amine), Poly(N-heptanoyl-ethyleneamine),
Poly(N-hexanoyl-ethyleneamine), Poly(N-isobutyryl-ethylene amine),
Poly(N-isovaleryl-ethylene amine), Poly(N-octanoyl-ethylene amine),
Poly(N-2-naphthoyl-ethylene amine), Poly(N-p-toluoyl-ethylene
amine), Poly(N-perfluorooctaoyl-ethylene amine),
Poly(N-perfluoropropionyl-ethylene amine),
Poly(N-pivaloyl-ethyleneamine), Poly(N-valeryl-ethyleneamine),
Poly(trimethyleneamine), Polysilane, Poly(di-N-hexyl-silane),
Poly(di-N-pentyl-silane), Poly(vinyltriethoxysilane),
Poly(vinyltrimethoxysilane), Poly(vinyltrimethylsilane), Poly(vinyl
methyldiacetoxysilane), Poly(vinyl methyldiethoxysilane),
Poly(vinylphenyldimethylsilane), Polysiloxane,
Poly(diethylsiloxane), Poly(dimethylsiloxane),
Poly(diphenylsiloxane), Poly(dipropylsiloxane),
Poly(pentaphenyl-p-toluoyltrsiloxane),
Poly(phenyl-p-toluoylsiloxane), Polytphthalocyaninato-siloxane),
Poly(propylmethylsiloxane), Poly(ethylmethylsiloxane),
Poly(methyloctylsiloxane),
Poly(3,3,3-trifluoropropylmethylsiloxane),
Poly(vinylmethylsiloxane), Polysilylene, Poly(dimethylsilylene),
Poly(diphenylsilylene), Poly(dimethyldiallylsilane),
Poly[oxydi(pentafluorophenyl)silylenedi(oxydimethylsilylene)],
Poly[oxymethylchlorotetrafluorophenylsilylenedi(oxydimethylsilylene)],
Poly(oxymethylpentafluorophenylsilylene),
Poly(oxymethylpentafluorophenylsilyleneoxydimethylsilylene,
Poly[oxymethylpentafluorophenylsilylenedi(oxydimethylsilylene)],
Poly(oxymethyl-3,3,3-trifluoropropylsilylene),
Poly(oxymethylphenylsilylene),
Poly[tri(oxydimethylsilylene)oxy(methyl)trimethylsiloxysilylene],
Poly[tri(oxydimethylsilylene)oxy(methyl)-2-phenyl-ethylsilylene],
Poly[(4-dimethylaminophenyl)methylsilylenetrimethylene],
Poly[(4-dimethylaminophenyl)phenylsilylenetrimethylene],
Poly[(methyl)phenylsilylenetrimethylene],
Poly(1,1-dimethylsilazane), Poly(dimethylsilylenetrimethylene),
Poly(di-p-tolylsilylenetrimethylene), Poly(phosphazene),
Poly(bis-beta-naphthoxy-phosphazene),
Poly(bis-phenoxy-phosphazene),
Poly(di-p-methyl-bis-phenoxy-phosphazene),
Poly(di-p-chloro-bis-phenoxy-phosphazene),
Poly(di-2,4-dichloro-bis-phenoxy-phosphazene),
Poly(di-p-phenyl-bis-phenoxy-phosphazene),
Poly(di-m-trifluoromethyl-phosphazene),
Poly(di-methyl-phosphazene), Poly(dich-oro-phosphazene),
Poly(diethoxy-phosphazene), Poly[bis(ethylamino)phosphazene],
Poly[bis(2,2,2-trifluoroethoxy)phosphazene],
Poly[bis(3-trifluoromethylphenoxy)phosphazene],
Poly[bis(1H,1H-pentadecafluorooctyloxy)phosphazene],
Poly[bis(1H,1H-pentafluoropropoxy)phosphazene],
Poly(dimethoxy-phosphazene), Poly[bis(phenylamino)phosphazene],
Poly[bis(piperidino)phosphazene], Poly(diethylpropenyl phosphate),
Poly(diethylisopropenyl phosphate), Poly[vinyl
bis(chloroethyl)phosphate], Poly(vinyldisethylphosphate),
Poly(vinyldiethyl phosphate), Poly(vinyldiphenyl phosphate),
Poly(alpha-bromovinyl diethyl phosphonate),
Poly(alpha-carboethoxyvinyl diethyl phosphonate),
Poly(alpha-carbomethoxyvinyl diethyl phosphonate), Poly(isopropenyl
dimethyl phosphonate), Poly[vinyl bis(2-chloroethyl)phosphonate],
Poly(vinyl dibutyl phosphonate), Poly(vinyl diethyl phosphonate),
Poly(vinyldiisobutyl phosphonate), Poly(vinyl diisopropyl
phosphonate), Poly(vinyl dimethyl phosphonate), Poly(vinyl diphenyl
phosphonate), Poly(vinyl dipropyl phosphonate),
Poly[2-(4-vinylphenyl)ethyl diethyl phosphonate),
Poly(4-vinylphenyl diethyl phosphonate), and Poly(diphenylvinyl
phosphine oxide).
[0075] Method of Manufacture
[0076] A method of responsive microgel synthesis and production is
further an object of the present invention. The method of the
present invention involves a single synthetic step, which is
advantageous for scale-up of responsive microgel fabrication. The
synthesis of the microgels described herein involves a free-radical
copolymerization of a vinyl monomer with a divinyl cross-linker
with simultaneous hydrogen abstraction from a polymer present in
the reaction system. The hydrogen abstraction leads to generation
of macro-radicals that lead to the grafting of the amphiphilic
copolymer `dangling chains` onto the growing microgel network. The
series of reactions that occur simultaneously and yield a
responsive microgel of the present invention are shown in FIG. 4
(scheme of the one-step synthesis of responsive microgels). See,
e.g., Examples I and II.
[0077] A preferred chain-transfer reaction to covalently bond the
nonionic copolymer to the ionizable network is a free-radical
polymerization (using a redox free-radical initiator) of an
ionizable monomer and a divinyl cross-linker.
[0078] A method of making the responsive microgel covalently
cross-linked polymer network (graft-comb copolymer) of the present
invention, for example, comprises the steps of: a) providing, an
ionizable monomer, a divinyl cross-linker, a free radical, and a
nonionic copolymer; and, b) copolymerizing the ionizable monomer
with the divinyl cross-linker to produce an ionizable network,
while c) abstracting hydrogen from the nonionic copolymer with the
free radical to progress a chain transfer reaction wherein the
nonionic copolymer is covalently bonded onto the ionizable network
to produce a responsive microgel as defined herein.
[0079] Divinyl cross-linker as used herein refers to a reactive
chemical having at least two ethylenic double bonds capable of
participating in at least two growing polymer chains. Examples of
cross-linkers of this type, which are normally used as crosslinkers
in polymerization reactions, are N,N'-methylenebisacrylamide,
polyethylene glycol diacrylates and polyethylene glycol
dimethacrylates which are derived in each case from polyethylene
glycols with a molecular weight of from 106 to 8500, preferably 400
to 2000, trimethylolpropane triacrylate, trimethylolpropane
trimethacrylate, ethylene glycol diacrylate, propylene glycol
diacrylate, butanediol diacrylate, hexanediol diacrylate,
hexanediol dimethacrylate, diacrylates and dimethacrylates of block
copolymers of ethylene oxide and propylene oxide, polyhydric
alcohols such as glycerol or pentaerythritol which are esterified
two or three times with acrylic acid or methacrylic acid,
triallylamine, tetraallylethylenediamine, divinylbenzene, diallyl
phthalate, polyethylene glycol divinyl ethers of polyethylene
glycols with a molecular weight of from 126 to 4000,
trimethylolpropane diallyl ether, butanediol divinyl ether,
pentaerythritol triallyl ether and/or divinylethyleneurea.
Water-soluble crosslinkers are preferably used, e.g.
N,N'-methylenebisacrylamide, oligoethylene glycol diacrylates and
oligoethylene glycol dimethacrylates derived from adducts of 2 to
400 mol of ethylene oxide and 1 mol of a diol or polyol, vinyl
ethers of adducts of 2 to 400 mol of ethylene oxide and 1 mol of a
diol or polyol, ethylene glycol diacrylate, ethylene glycol
dimethacrylate or triacrylates and trimethacrylates of adducts of 6
to 20 mol of ethylene oxide and one mol of glycerol,
pentaerythritol triallyl ether and/or divinylurea.
[0080] Also suitable as crosslinkers are compounds, which contain
at least one polymerizable ethylenically unsaturated group and at
least one other functional group. The functional group in these
crosslinkers must be able to react with the functional groups,
essentially the carboxyl groups in the monomers of the backbone.
Examples of suitable functional groups are hydroxyl, amino, epoxy
and aziridino groups.
[0081] Also suitable as crosslinkers are those compounds which have
at least two functional groups able to react with carboxyl and
other functional groups in the monomers used. The suitable
functional groups have already been mentioned above, i.e. hydroxyl,
amino, epoxy, isocyanate, ester, amide and aziridino groups.
Examples of such crosslinkers are ethylene glycol, diethylene
glycol, triethylene glycol, tetraethylene glycol, polyethylene
glycol, glycerol, polyglycerol, propylene glycol, polypropylene
glycol, block copolymers of ethylene oxide and propylene oxide,
sorbitan fatty acid esters, ethoxylated sorbitan fatty acid esters,
trimethylolpropane, pentaerythritol, polyvinyl alcohol, sorbitol,
polyglycidyl ethers such as ethylene glycol diglycidyl ether,
polyethylene glycol diglycidyl ether, glycerol diglycidyl ether,
glycerol polyglycidyl ether, diglycerol polyglycidyl ether,
polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether,
pentaerythritol polyglycidyl ether, propylene glycol diglycidyl
ether and polypropylene glycol diglycidyl ether, polyaziridine
compounds such as 2,2-bishydroxymethylbutanol
tris[3-(1-aziridinyl)propionate], 1,6-hexamethylenediethyleneurea,
4,4'-methylenebis(phenyl)-N,N'-diethyleneurea, halo epoxy compounds
such as epichlorohydrin and a-methylfluorohydrin, polyisocyanates
such as 2,4-tolylene diisocyanate and hexamethylene diisocyanate,
alkylene carbonates such as 1,3-di-oxolan-2-one and
4-methyl-1,3-dioxolan-2-one, polyquaternary amines such as
condensates of dimethylamine with epichlorohydrin, homo- and
copolymers of diallyldimethylammonium chloride, and homo- and
copolymers of dimethylaminoethyl (meth)acrylate, which are, where
appropriate, quaternized with, for example, methyl chloride.
[0082] Other suitable crosslinkers are polyvalent metal ions able
to form ionic crosslinks. Examples of such crosslinkers are
magnesium, calcium, barium and aluminum ions. A preferred
crosslinker of this type is sodium aluminate. These crosslinkers
are added, for example, as hydroxides, carbonates or bicarbonates
to the aqueous polymerizable solution.
[0083] Other suitable crosslinkers are multifunctional bases which
are likewise able to form ionic crosslinks, for example polyamines
or their quaternized salts. Examples of polyamines are
ethylenediamine, diethylenetriamine, triethylenetetramine,
tetraethylenepentamine, pentaethylenehexamine and
polyethyleneimines, and polyvinylamines with molecular weights of
up to 4,000,000 in each case.
[0084] In a preferred embodiment of the invention, divinyl
crosslinkers are used. These can be hydrophobic or most preferably
amphiphilic or hydrophilic. Apart from polyvalent metal ions, all
the water-insoluble crosslinkers which are described above and can
be assigned to the various groups are suitable for producing gels.
Some preferred hydrophobic crosslinkers are diacrylates or
dimethacrylates or divinyl ethers of alkanediols with 2 to 25
carbon atoms (branched, linear, with any suitable arrangement of OH
groups) such as 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol,
neopentyl glycol, 1,9-nonanediol or 1,2-dodecanediol, di-, tri- or
polypropylene glycol diacrylates or dimethacrylates, allyl
acrylate, allyl methacrylate, divinylbenzene, glycidyl acrylate or
glycidyl methacrylate, allyl glycidyl ether and bisglycidyl ethers
of the alkanediols listed above.
[0085] Examples of suitable hydrophilic crosslinkers are
N,N'-methylenebisacrylamide, polyethylene glycol diacrylates or
dimethacrylates with a molecular weight from 200 to 4000,
divinylurea, triallylamine, diacrylates or dimethacrylates of
adducts of from 2 to 400 mol of ethylene oxide and 1 mol of a diol
or polyol or the triacrylate of an adduct of 20 mol of ethylene
oxide and 1 mol of glycerol and vinyl ethers of adducts of from 2
to 400 mol of ethylene oxide and 1 mol of a diol or polyol.
[0086] The polymerization initiators which can be used are all
initiators which form free radicals under the polymerization
conditions and which are normally used in the preparation of
responsive gels. It is also possible to initiate the polymerization
by the action of electron beams on the polymerizable aqueous
mixture. However, the polymerization can also be started in the
absence of initiators of the abovementioned type by the action of
high-energy radiation in the presence of photoinitiators.
[0087] Polymerization initiators which can be used are all
compounds which decompose to free radicals under the polymerization
conditions, eg. peroxides, hydroperoxides, hydrogen peroxide,
persulfates, azo compounds and the redox catalysts. Initiators
soluble in the mixture of the monomer and amphiphilic copolymer are
preferably used. It is advantageous in some cases to use mixtures
of various polymerization initiators, e.g. most preferably mixtures
of lauroyl peroxide or benzoyl peroxide hydrogen peroxide with
2,2'-azobis(2,4-dimethylpentanenitrile) or
4,4'-azobis(4-cyanovaleric acid). Examples of suitable organic
peroxides are acetylacetone peroxide, methyl ethyl ketone peroxide,
tertbutyl hydroperoxide, cumene hydroperoxide, tert-amyl
perpivalate, tert-butyl perpivalate, tert-butyl perneohexanoate,
tert-butyl perisobutyrate, tert-butyl per-2-ethylhexanoate,
tert-butyl perisononanoate, tert-butyl permaleate, tert-butyl
perbenzoate, di(2-ethylhexyl)peroxydicarbonate, dicyclohexyl
peroxydicarbonate, di(4-tert-butylcyclohexyl)peroxydicarbonate,
dimyristyl peroxydicarbonate, diacetyl peroxydicarbonate, allyl
peresters, cumyl peroxyneodecanoate, tert-butyl
per-3,5,5-trimethylhexanoate, acetyl cyclohexylsulfonyl peroxide,
dilauroyl peroxide, dibenzoyl peroxide and tert-amyl
perneodecanoate. Also suitable polymerization initiators are
water-soluble azo initiators, eg.
2,2'-azobis(2-amidinopropane)dihydrochloride,
2,2'-azobis(N,N'-dimethyleneisobutyramidine)dihydrochloride,
2-(carbamoylazo)isobutyronitrile,
2,2'-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride and
4,4,-azobis(4-cyanovaleric acid). Polymerization initiators are
used in conventional amounts, e.g. in amounts of from 0.01 to 5,
preferably 0.1 to 2.0, % of the weight of the monomers to be
polymerized.
[0088] Also suitable as initiators are redox catalysts. The redox
catalysts contain as oxidizing component at least one of the
abovementioned peroxy compounds and as reducing component, for
example, ascorbic acid, glucose, sorbose, ammonium or alkali metal
bisulfite, sulfite, thiosulfate, hyposulfite, pyrosulfite or
sulfide, metal salts such as iron(II) ions or silver ions, or
sodium hydroxymethylsulfoxylate. The reducing component preferably
used in the redox catalyst is ascorbic acid or sodium sulfite.
Based on the amount of monomers used in the polymerization, for
example, from 3.times.10.sup.-6 to 1 mol % of the reducing
component of the redox catalyst system and from 0.001 to 5.0 mol %
of the oxidizing component of the redox catalyst are used.
[0089] If the polymerization is initiated by the action of
high-energy radiation, photoinitiators are normally used as
initiator. These may be, for example, alpha-splitters,
H-abstracting systems or else azides. Examples of initiators of
these types are benzophenone derivatives such as Michler's ketone,
phenanthrene derivatives, fluorene derivatives, anthraquinone
derivatives, thioxanthone derivatives, coumarin derivatives,
benzoin ethers and derivatives thereof, azo compounds like the
free-radical formers mentioned above, substituted
hexaarylbisimidazoles or acylphosphine oxides. Examples of azides
are: 2-(N,N-dimethylamino)ethyl 4-azidocinnamate,
2-(N,N-dimethylamino)ethyl-4-azidonaphthyl ketone,
2-(N,N-dimethylamino)ethyl 4-azidobenzoate, 5-azido-1-naphthyl
2-(N,N-dimethylamino)ethyl sulfone,
N-(4-sulfonylazidophenyl)maleimide,
N-acetyl-4-sulfonylazidoaniline, 4-sulfonylazido-aniline,
4-azidoaniline, 4-azidophenacyl bromide, p-azidobenzoic acid,
2,6-bis(p-azidobenzylidene)cyclohexanone and
2,6-bis(p-azidobenzylidene)-4-methylcyclohexanone. The
photoinitiators are, if employed, normally used in amounts of from
0.01 to 5% of the weight of the monomers to be polymerized.
[0090] In one embodiment, it is preferred to use free-radical
initiators capable of abstracting tertiary and secondary hydrogens
from the backbone of the amphiphilic polymer of the present
invention.
[0091] Methods of Use
[0092] One of the major concerns in the delivery of drugs is the
bioavailability of the drug. Depending upon the nature of the drug
and the route of delivery, the bioavailability may be very low due
to, for example, the degradation of oral-delivered drugs by
hepato-gastrointestinal first-pass elimination or rapid clearance
of the drug from the site of application. The net result is that
frequent dosing may be required with higher than needed amounts of
drug, which can lead to undesired side effects. Thus, it is desired
by the pharmaceutical industry to have ways of administering drugs
such that their availability can be controlled in an even dosing
manner, the amounts of drugs can be kept as low as possible to
minimize side effects, and dosing regime can be kept to a minimum
to provide greater convenience to the subject, thus promoting
greater compliance with appropriate dosing.
[0093] The responsive microgels of the present invention are useful
in a wide variety of chemo-mechanical applications in that they
display diverse phase transition characteristics. A method, for
example, of delivering at least one therapeutic or cosmetic agent
to a mammalian subject is a preferred embodiment of the invention
which comprises administering a responsive microgel of the present
invention to the subject which comprises at least one such
agent.
[0094] A method of delivering an effective amount at least one
therapeutic agent to a patient is a preferred method of the
invention which comprises administering an effective amount of a
responsive microgel of the present invention which comprises at
least one therapeutic agent. Therapeutic regimens for the
prevention and/or treatment of cancer frequently requires, for
example, the administration of an effective amount of a cationic,
hydrophobic, and/or amphiphilic compound, individually or in
combinations. The responsive microgel of the present invention is
particularly suited for therapeutic administration of these types
of agents or entities. The responsive microgels are provided as a
long-term delivery device for therapeutic agents and to enhance the
therapeutic profile. The responsive microgels provide improved and
substantially linear sustained release of therapeutic agents to
improve and prolong the bioavailability of the agent. The
reversibly gelling responsive microgel of this invention has the
physico-chemical characteristics that make it a suitable delivery
vehicle for conventional small chemical drugs as well as new
macromolecular (e.g., peptides) drugs or therapeutic products.
[0095] The responsive microgel of the present invention is
particularly suited for oral administration. The responsive
microgel of the present invention may also be employed to deliver
therapeutic entities (including cosmetic agents), for example, by
intranasal, ocular, pulmonary, colonic, vaginal, as well as topical
administration. The temperature-responsive mode of solute
solubilization, for example, by microgels of the present invention
is useful for medicinal as well as cosmetic formulations. Preferred
therapeutic entities for use in the present invention include but
are not limited to doxorubicin, mitoxantrone, mitomycin C, as well
as the Taxanes including but not limited to (paclitaxel
(TAXOL.RTM.), and docetaxel (TAXOTERE.RTM.)).
[0096] Examples of therapeutic entities that might be utilized in a
delivery application of the invention include literally any
hydrophilic or hydrophobic biologically active compound.
Preferably, though not necessarily, the drug is one that has
already been deemed safe and effective for use by the appropriate
governmental agency or body. For example, drugs for human use
listed by the FDA under 21 C.F.R. 330.5, 331 through 361; 440-460;
drugs for veterinary use listed by the FDA under 21 C.F.R. 500-582,
incorporated herein by reference, are all considered acceptable for
use in the present responsive microgel.
[0097] Drugs that are not themselves liquid at body temperature can
be incorporated into the responsive microgel of the present
invention. Moreover, peptides and proteins which may normally be
rapidly degraded by tissue-activated enzymes such as peptidases,
can be passively protected in the microgels described herein.
[0098] A responsive microgel which comprises at least one
therapeutic entity is particularly preferred. A responsive microgel
which comprises at least one anticancer agent is a preferred
embodiment of the present invention wherein, for example, at least
one anticancer agent is selected from the group consisting of (a
steroidal antiandrogen, a non steroidal antiandrogen, an estrogen,
diethylstilbestrol, a conjugated estrogen, a selective estrogen
receptor modulator (SERM), a taxane, and a LHRH analog). Non
steroidal antiandrogen as referred to herein includes but is not
limited to the group consisting essentially of (finasteride
(PROSCAR.RTM.), flutamide (4'-nitro-3'-trifluorormethyl
isobutyranilide), bicalutamide (CASODEX.RTM.), and nilutamide).
SERM as referred to herein includes but is not limited to the group
consisting essentially of (tamoxifen, raloxifene, droloxifene, and
idoxifene). LHRH analog as referred to herein includes but is not
limited to the group consisting essentially of (goserelin acetate
(ZOLADEX.RTM.), and leuprolide acetate (LUPRON.RTM.)).
[0099] A method of prevention or treatment of a tumor is provided
comprising administering a therapeutically effective amount of a
responsive microgel which comprises at least one therapeutic entity
to a patient wherein the patient is either at risk of developing a
tumor or already exhibits a tumor. A method of prevention or
treatment of a tumor is provided wherein at least one agent
described herein--or a stereoisomeric mixture thereof,
diastereomerically enriched, diastereomerically pure,
enantiomerically enriched or enantiomerically pure isomer thereof,
or a prodrug of such compound, mixture or isomer thereof, or a
pharmaceutically acceptable salt of the compound, mixture, isomer
or prodrug--is administered in a therapeutically effective amount
comprised within a responsive microgel of the present invention to
a patient wherein the patient is either at risk of developing a
tumor or already exhibits a tumor. Methods of employing the
responsive microgel of the present invention for the prevention or
treatment of a tumor is provided wherein at least one agent is
comprised within the microgel selected from the group consisting of
(a steroidal antiandrogen, a non steroidal antiandrogen, an
estrogen, diethylstilbestrol, a conjugated estrogen, a selective
estrogen receptor modulator (SERM), a taxane, and a LHRH analog)
and an effective amount of the microgel is administered to a
patient in need of treatment.
[0100] The term therapeutic entity includes pharmacologically
active substances that produce a local or systemic effect in a
mammal. The term thus means any substance intended for use in the
diagnosis, cure, mitigation, treatment or prevention of disease or
in the enhancement of desirable physical or mental development and
conditions in a mammal.
[0101] Therapeutic entities for employment with the responsive
microgels described herein therefore include small molecule
compounds, polypeptides, proteins, nucleic acids, and
PLURONIC.RTM., for example, as described herein (e.g., and for the
formation of mixed micelles).
[0102] Examples of proteins include antibodies, enzymes, growth
hormone and growth hormone-releasing hormone,
gonadotropin-releasing hormone, and its agonist and antagonist
analogues, somatostatin and its analogues, gonadotropins such as
luteinizing hormone and follicle-stimulating hormone, peptide-T,
thyrocalcitonin, parathyroid hormone, glucagon, vasopressin,
oxytocin, angiotensin I and II, bradykinin, kallidin,
adrenocorticotropic hormone, thyroid stimulating hormone, insulin,
glucagon and the numerous analogues and congeners of the foregoing
molecules.
[0103] Classes of pharmaceutically active compounds which can be
loaded onto responsive microgel compositions of the invention
include, but are not limited to, anti-AIDS substances, anti-cancer
substances, antibiotics, immunosuppressants (e.g. cyclosporine)
anti-viral substances, enzyme inhibitors, neurotoxins, opioids,
hypnotics, antihistamines, tranquilizers, anti-convulsants, muscle
relaxants and anti-Parkinson substances, anti-spasmodics and muscle
contractants, miotics and anti-cholinergics, antiglaucoma
compounds, anti-parasite and/or anti-protozoal compounds,
anti-hypertensives, analgesics, anti-pyretics and anti-inflammatory
agents such as NSAIDs, local anesthetics, ophthalmics,
prostaglandins, anti-depressants, anti-psychotic substances,
anti-emetics, imaging agents, specific targeting agents,
neurotransmitters, proteins, cell response modifiers, and
vaccines.
[0104] A more complete listing of classes of compounds suitable for
loading into polymers using the present methods may be found in the
Pharmazeutische Wirkstoffe (Von Kleemann et al. (eds) Stuttgart/New
York, 1987, incorporated herein by reference). Examples of
particular pharmaceutically active substances are presented
below:
[0105] Anti-AIDS substances are substances used to treat or prevent
Autoimmune Deficiency Syndrome (AIDS). Examples of such substances
include CD4, 3'-azido-3'-deoxythymidine (AZT),
9-(2-hydroxyethoxymethyl)-guanine acyclovir( ), phosphonoformic
acid, 1-adamantanamine, peptide T, and 2',3' dideoxycytidine.
[0106] Anti-cancer substances are substances used to treat or
prevent cancer. Examples of such substances include methotrexate,
cisplatin, prednisone, hydroxyprogesterone, medroxyprogesterone
acetate, megestrol acetate, diethylstilbestrol, testosterone
propionate, fluoxymesterone, vinblastine, vincristine, vindesine,
daunorubicin, doxorubicin, hydroxyurea, procarbazine,
aminoglutethimide, mechlorethamine, cyclophosphamide, melphalan,
uracil mustard, chlorambucil, busulfan, carmustine, lomusline,
dacarbazine (DTIC: dimethyltriazenomidazolecarboxamide),
methotrexate, fluorouracil, 5-fluorouracil, cytarabine, cytosine
arabinoxide, mercaptopurine, 6-mercaptopurine, thioguanine.
[0107] Antibiotics are art recognized and are substances which
inhibit the growth of or kill microorganisms. Antibiotics can be
produced synthetically or by microorganisms. Examples of
antibiotics include penicillin, tetracycline, chloramphenicol,
minocycline, doxycycline, vanomycin, bacitracin, kanamycin,
neomycin, gentamycin, erythromicin and cephalosporins.
[0108] Anti-viral agents are substances capable of destroying or
suppressing the replication of viruses. Examples of anti-viral
agents include a-methyl-P-adamantane methylamine,
1,-D-ribofuranosyl-1,2,4-triazole-3 carboxamide,
9->2-hydroxy-ethoxy!methylguanine, adamantanamine,
5-iodo-2'-deoxyuridine, trifluorothymidine, interferon, and adenine
arabinoside.
[0109] Enzyme inhibitors are substances which inhibit an enzymatic
reaction. Examples of enzyme inhibitors include edrophonium
chloride, N-methylphysostigmine, neostigmine bromide, physostigmine
sulfate, tacrine HCl, tacrine, 1-hydroxy maleate, iodotubercidin,
p-bromotetramisole, 10-(alpha-diethylaminopropionyl)-phenothiazine
hydrochloride, calmidazolium chloride,
hemicholinium-3,3,5-initrocatechol, diacylglycerol kinase inhibitor
I, diacylglycerol kinase inhibitor II, 3-phenylpropargylamine,
N.sup.6-monomethyl-L-arginine acetate, carbidopa,
3-hydroxybenzylhydrazine HCl, hydralazine HCl, clorgyline HCl,
deprenyl HCl,L(-)-, deprenyl HCl,D(+)-, hydroxylamine HCl,
iproniazid phosphate, 6-MeO-tetrahydro-9H-pyrido-indole, nialamide,
pargyline HCl, quinacrine HCl, semicarbazide HCl, tranylcypromine
HCl, N,N-diethylaminoethyl-2,2-diphenylvalerate hydrochloride,
3-isobutyl-1-methylxanthne, papaverine HCl, indomethacind,
2-cyclooctyl-2-hydroxyethylamine hydrochloride,
2,3-dichloro-a-methylbenzylamine PCMB),
8,9-dichloro-2,3,4,5-tetrahydro-1H-2-benzazepine hydrochloride,
p-aminoglutethimide, p-aminoglutethimide tartrate,R(+)-,
p-aminoglutethimide tartrate,S(-)-, 3-iodotyrosine,
alpha-methyltyrosine,L-, alpha-methyltyrosine,D L-, acetazolamide,
dichlorphenamide, 6-hydroxy-2-benzothiazolesulfonamide, and
allopurinol.
[0110] Neurotoxins are substances which have a toxic effect on the
nervous system, e.g. nerve cells. Neurotoxins include adrenergic
neurotoxins, cholinergic neurotoxins, dopaminergic neurotoxins, and
other neurotoxins. Examples of adrenergic neurotoxins include
N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine hydrochloride.
Examples of cholinergic neurotoxins include acetylethylcholine
mustard hydrochloride. Examples of dopaminergic neurotoxins include
6-hydroxydopamine HBr,
1-methyl-4-(2-methylphenyl)-1,2,3,6-tetrahydro-pyridine
hydrochloride, 1-methyl-4-phenyl-2,3-dihydropyridinium perchlorate,
N-methyl-4-phenyl-1,2,5,6-tetrahydropyridine HCl,
1-methyl-4-phenylpyridinium iodide.
[0111] Opioids are substances having opiate like effects that are
not derived from opium. Opioids include opioid agonists and opioid
antagonists. Opioid agonists include codeine sulfate, fentanyl
citrate, hydrocodone bitartrate, loperamide HCl, morphine sulfate,
noscapine, norcodeine, normorphine, thebaine. Opioid antagonists
include nor-binaltorphimine HCl, buprenorphine, chlornaltrexamine
2HCl, funaltrexamione HCl, nalbuphine HCl, nalorphine HCl, naloxone
HCl, naloxonazine, naltrexone HCl, and naltrindole HCl.
[0112] Hypnotics are substances which produce a hypnotic effect.
Hypnotics include pentobarbital sodium, phenobarbital,
secobarbital, thiopental and mixtures, thereof, heterocyclic
hypnotics, dioxopiperidines, glutarimides, diethyl isovaleramide,
a-bromoisovaleryl urea, urethanes and disulfanes.
[0113] Antihistamines are substances which competitively inhibit
the effects of histamines. Examples include pyrilamine,
chlorpheniramine, tetrahydrazoline, and the like.
[0114] Lubricants are substances that increase the lubricity of the
environment into which they are delivered. Examples of biologically
active lubricants include water and saline.
[0115] Tranquilizers are substances which provide a tranquilizing
effect. Examples of tranquilizers include chloropromazine,
promazine, fluphenzaine, reserpine, deserpidine, and
meprobamate.
[0116] Anti-convulsants are substances which have an effect of
preventing, reducing, or eliminating convulsions. Examples of such
agents include primidone, phenyloin, valproate, Chk and
ethosuximide.
[0117] Muscle relaxants and anti-Parkinson agents are agents which
relax muscles or reduce or eliminate symptoms associated with
Parkinson's disease. Examples of such agents include mephenesin,
methocarbomal, cyclobenzaprine hydrochloride, trihexylphenidyl
hydrochloride, levodopa/carbidopa, and biperiden.
[0118] Anti-spasmodics and muscle contractants are substances
capable of preventing or relieving muscle spasms or contractions.
Examples of such agents include atropine, scopolamine,
oxyphenonium, and papaverine.
[0119] Miotics and anti-cholinergics are compounds which cause
bronchodilation. Examples include echothiophate, pilocarpine,
physostigmine salicylate, diisopropylfluorophosphate, epinephrine,
neostigmine, carbachol, methacholine, bethanechol, and the
like.
[0120] Anti-glaucoma compounds include betaxalol, pilocarpine,
timolol, timolol salts, and combinations of timolol, and/or its
salts, with pilocarpine.
[0121] Anti-parasitic, -protozoal and -fungals include ivermectin,
pyrimethamine, trisulfapyrimidine, clindamycin, amphotericin B,
nystatin, flucytosine, natamycin, and miconazole.
[0122] Anti-hypertensives are substances capable of counteracting
high blood pressure. Examples of such substances include
alpha-methyldopa and the pivaloyloxyethyl ester of
alpha-methyldopa.
[0123] Analgesics are substances capable of preventing, reducing,
or relieving pain. Examples of analgesics include morphine sulfate,
codeine sulfate, meperidine, and nalorphine.
[0124] Anti-pyretics are substances capable of relieving or
reducing fever and anti-inflammatory agents are substances capable
of counteracting or suppressing inflammation. Examples of such
agents include aspirin (salicylic acid), indomethacin, sodium
indomethacin trihydrate, salicylamide, naproxen, colchicine,
fenoprofen, sulindac, diflunisal, diclofenac, indoprofen and sodium
salicylamide.
[0125] Local anesthetics are substances which have an anesthetic
effect in a localized region. Examples of such anesthetics include
procaine, lidocain, tetracaine and dibucaine.
[0126] Ophthalmics include diagnostic agents such as sodium
fluorescein, rose bengal, methacholine, adrenaline, cocaine, and
atropine. Ophthalmic surgical additives include alpha-chymotrypsin
and hyaluronidase.
[0127] Prostaglandins are art recognized and are a class of
naturally occurring chemically related, long-chain hydroxy fatty
acids that have a variety of biological effects.
[0128] Anti-depressants are substances capable of preventing or
relieving depression. Examples of anti-depressants include
imipramine, amitriptyline, nortriptyline, protriptyline,
desipramine, amoxapine, doxepin, maprotiline, tranylcypromine,
pheneizine, and isocarboxazide.
[0129] Anti-psychotic substances are substances which modify
psychotic behavior. Examples of such agents include phenothiazines,
butyrophenones and thioxanthenes.
[0130] Anti-emetics are substances which prevent or alleviate
nausea or vomiting. An example of such a substance includes
dramamine.
[0131] In topical skin care applications, a variety of active
substances may be advantageously employed. By way of example only
suitable active agents which may be incorporated into the cosmetic
composition include anti-aging active substances, anti-wrinkle
active substances, hydrating or moisturizing or slimming active
substances, depigmenting active substances, substances active
against free radicals, anti-irritation active substances, sun
protective active substances, anti-acne active substances,
firming-up active substances, exfoliating active substances,
emollient active substances, and active substances for the treating
of skin disorders such as dermatitis and the like.
[0132] Imaging agents are agents capable of imaging a desired site,
e.g. tumor, in vivo. Examples of imaging agents include substances
having a label which is detectable in vivo, e.g. antibodies
attached to fluorescent labels. The term antibody includes whole
antibodies or fragments thereof.
[0133] Specific targeting agents include agents capable of
delivering a therapeutic agent to a desired site, e.g. tumor, and
providing a therapeutic effect. Examples of targeting agents
include agents which can carry toxins or other agents which provide
beneficial effects. The targeting agent can be an antibody linked
to a toxin, e.g. ricin A or an antibody linked to a drug.
[0134] Neurotransmitters are substances which are released from a
neuron on excitation and travel to either inhibit or excite a
target cell. Examples of neurotransmitters include dopamine,
serotonin, q-aminobutyric acid, norepinephrine, histamine,
acetylcholine, and epinephrine.
[0135] Cell response modifiers are chemotactic factors such as
platelet-derived growth factor (PDGF). Other chemotactic factors
include neutrophil-activating protein, monocyte chemoattractant
protein, macrophage-inflammatory protein, platelet factor, platelet
basic protein, and melanoma growth stimulating activity; epidermal
growth factor, transforming growth factor (alpha), fibroblast
growth factor, platelet-derived endothelial cell growth factor,
insulin-like growth factor, nerve growth factor, and bone
growth/cartilage-inducing factor (alpha and beta), or other bone
morphogenetic protein.
[0136] Other cell response modifiers are the interleukins,
interleukin inhibitors or interleukin receptors, including
interleukin 1 through interleukin 10; interferons, including alpha,
beta and gamma; hematopoietic factors, including erythropoietin,
granulocyte colony stimulating factor, macrophage colony
stimulating factor and granulocyte-macrophage colony stimulating
factor; tumor necrosis factors, including alpha and beta;
transforming growth factors (beta), including beta-1, beta-2,
beta-3, inhibin, and activin; and bone morphogenetic proteins.
[0137] As those skilled in the art will appreciate, the foregoing
list is exemplary only. Because the responsive microgel of the
present invention is suited for application under a variety of
physiological conditions, a wide variety of pharmaceutical agents
may be loaded onto the responsive microgels described herein and
administered.
[0138] Formulations
[0139] Tablet Excipients. It has been demonstrated that standard
pharmaceutical processes, such as lyophilization and air-drying can
process the responsive microgel of the invention. The reversible
thermal viscosifying responsive microgel may be reconstituted with
water, phosphate buffer or calcium chloride solution, without loss
or degradation of rheological properties. Thus, it is contemplated
that the responsive microgel of the invention may also be
incorporated as excipients into tablets or granules for oral
delivery, for example. The responsive microgel may be coated on an
outer surface of the tablet or may be introduced in powder form
into the tablet along with the active agent and other ingredients.
The poloxamer:poly(acrylic acid) composition may be used to promote
bioadhesion of the tablet and its contents with the mucosal lining
of the gastro-intestinal tract to extend transit time.
[0140] Also, when incorporated as a powder, the slow dissolution
rate of the end-modified responsive microgel makes it a suitable
excipient to sustained release tableting formulation. The addition
of such responsive microgel would yield to a slow release of the
incorporated drug.
[0141] Injectibles. The end-modified responsive microgel
composition of the invention is well-suited for use in injectable
applications. A depot formulation may be prepared and administered
at low viscosity to a subdermal or intramuscular site, for example.
The responsive microgel will viscosify and form a depot site, which
will slowly release the active agent. The reversible thermally
viscosifying responsive microgel, upon contact with body fluids
including blood or the like, undergoes gradual release of the
dispersed drug for a sustained or extended period (as compared to
the release from an isotonic saline solution). This can result in
prolonged delivery (over, say 1 to 2,000 hours, preferably 2 to 800
hours) of effective amounts (say, 0.0001 mg/kg/hour to 10
mg/kg/hour) of the drug. This dosage form can be administered as is
necessary depending on the subject being treated, the severity of
the affliction, the judgment of the prescribing physician, and the
like.
[0142] Preparation of Pharmaceutic Compositions May be Accomplished
with Reference to any of the pharmaceutic formulation guidebooks
and industry journals which are available in the pharmaceutic
industry. These references supply standard formulations which may
be modified by the addition or substitution of the reversible
viscosifying composition of the present invention into the
formulation. Suitable guidebooks include Pharmaceutics and
Toiletries Magazine, Vol. 111 (March, 1996); Formulary: Ideas for
Personal Care; Croda, Inc, Parsippany, N.J. (1993); and
Pharmaceuticon: Pharmaceutic Formulary, BASF, which are hereby
incorporated in their entirety by reference.
[0143] The pharmaceutic composition may be in any form. Suitable
forms will be dependant, in part, of the intended mode and location
of application. Ophthalmic and otic formulations are preferably
administered in droplet or liquid form; nasal formulations are
preferable administered in droplet or spray form, or may be
administered as a powder (as a snuff); vaginal and rectal
formulations are preferably administered in the form of a cream,
jelly or thick liquid; veterinary formulations may be administered
as a cream, lotion, spray or mousse (for application to fur or
exterior surface); esophageal and buccal/oral cavity applications
are preferably administered from solution or as a powder; film
forming applications or dermal applications may be administered as
a lotions, creams, sticks, roll-ons formulations or pad-applied
formulations.
[0144] Exemplary drugs or therapeutics delivery systems which may
be administered using the aqueous responsive composition
compositions of the invention include, but are in no way limited
to, mucosal therapies, such as esophageal, otic, rectal, buccal,
oral, vaginal, and urological applications; topical therapies, such
as wound care, skin care and teat dips; and
intravenous/subcutaneous therapies, such as intramuscular,
intrabone (e.g., joints), spinal and subcutaneous therapies, tissue
supplementation, adhesion prevention and parenteral drug delivery.
In addition, further applications include transdermal delivery and
the formation of depots of drug following injection. It will be
appreciated that the ionic nature of the biocompatible component of
the responsive composition provides an adhesive interaction with
mucosal tissue.
[0145] The responsive microgels of the present invention may be
understood with reference to the following examples, which are
provided for the purposes of illustration of example embodiments,
and are not intended to limit the scope of the claims appended
hereto.
EXAMPLES
Example I
Drug Release from Responsive Microgels of Polyether-Modified
Poly(Acrylic Acid)
[0146] PLURONIC.RTM. F127 NF, L92 and L61 were obtained from BASF
Corp. (Mount Olive, N.J.) and used as received. The properties of
these PLURONIC.RTM. surfactants are presented in Table 1:
TABLE-US-00005 TABLE 1 Properties of the PLURONIC .RTM. surfactants
used in this study. M. Yu. Kozlov, Macromolecules, 2000, 33,
3305-3313; M. J. Kositza, et al., Langmuir, 1999, 15, 322-325; BASF
Catalog. Number Number Hydrophilic- Cloud point Critical micelle
Nominal of PO of EO lipophilic in water at 1 concentration at
Copolymer MW units units balance wt %, .degree. C. 25.degree. C., M
L61 2000 30 6 3 32 1.1 .times. 10.sup.-4 L92 3650 60 16 6 69 8.8
.times. 10.sup.-5 F127 12600 65 200 22 >100 2.8 .times.
10.sup.-6
[0147] Materials
[0148] A fluorescent dye, 5-(4,6-dichlorotriazinyl)aminofluorescein
(DCTAF, 99%) was obtained from Molecular Probes, Inc. (Eugene,
Oreg.). Acrylic acid (99%, vinyl monomer), ethylene glycol
dimethacrylate (98%, divinyl cross-linker, EGDMA), dodecane (99+%,
solvent), 4,4'-azobis(4-cyanovaleric acid) (75+%, azo initiator),
and lauroyl peroxide (97%, redox initiator) were purchased from
Aldrich Chemical Co. and used as received.
Poly(vinylpyrrolidinone-co-1-hexadecene) (Ganex V-216) (dispersion
stabilizer) was obtained from International Specialty Products
(Wayne, N.J.). Doxorubicin hydrochloride of 99% purity was obtained
from Hande Tech USA (Houston, Tex.), a subsidiary of Yunnan Hande
Technological Development Co. (Kunming, P. R. China). All other
chemicals, gases and organic solvents of the highest purity
available were obtained from commercial sources.
[0149] Microgel Synthesis
[0150] Synthesis was carried out on a laboratory scale in an
adiabatic mode. Acrylic acid (vinyl monomer) (40 mL) was partially
neutralized by addition of 5 M NaOH aqueous solution (0.5 mL).
PLURONIC.RTM. F127 or L92 (24 g) was dissolved in the resulting
solution under nitrogen and a desired amount of ethylene glycol
dimethacrylate (EGDMA) (divinyl cross-linker) was added. Amounts of
EGDMA were set such that resulted in 1 mol % relative degree of
cross-linking of the microgels [cross-linking mol
%=100.times.(number of mols of EGDMA/the number of mols of acrylic
acid)]. Lauroyl peroxide (redox initiator) (100 mg) and
4,4'-azobis(4-cyanovaleric acid) (azo initiator) (100 mg) were
dissolved in 2 mL of acrylic acid (vinyl monomer) and added to the
solution of PLURONIC.RTM. in acrylic acid. The resulting solution
was deaerated by nitrogen bubbling for 0.5 h and added to a
3-necked 0.5-mL flask containing 1 wt % solution of Ganex V-216
(dispersion stabilizer) in dodecane (solvent) (200 mL). The flask
was vigorously stirred by a mechanical stirrer and deaerated by
constant nitrogen purge from the bottom. Then the flask was heated
to 70.degree. C. using an oil bath and kept at that temperature
under stirring and nitrogen purge. After about 1 h, formation of
white particles was observed on the flask walls. The reaction was
continued at 70.degree. C. for another 3 h. Then the reactor was
disassembled, and the contents of the reactor were filtered using
Whatman filter paper (retention size 10 .mu.m). The microgel
particles were extensively washed by hexane and dried under vacuum.
Spherical particles were observed under microscope. Particle sizing
was performed in hexane using a ZetaPlus Zeta Potential Analyzer
(Brookhaven Instruments Co.). Typical batches of particles made
with PLURONIC.RTM. F127 and L92 were measured to have effective
median diameter of 13 .mu.m (polydispersity 1.4) and 6 .mu.m
(polydispersity 1.3), respectively.
[0151] In order to ascertain the grafting of PLURONIC.RTM. segments
onto cross-linked poly(acrylic acid) [poly(vinyl monomer)]
networks, a particulate sample was suspended in 1 M NaOH for 3 days
and lyophilized. The sample was then placed into a Soxhlet
extractor charged with dichloromethane and kept under reflux for 2
days. The wash-outs were collected, evaporated under vacuum, and
weighed. Preliminary experiments demonstrated negligible solubility
of poly(sodium acrylate), and total solubility of the
PLURONIC.RTM., respectively, in dichloromethane. The fraction of
the PLURONIC.RTM. washed from the particles was negligible, within
experimental error (.+-.5% of the initial PLURONIC.RTM. content).
Hence, for all practical purposes, the overall composition of the
microgels in the present study corresponded to that set in the
reactor. That is, the weight ratio of PLURONIC.RTM. to poly(acrylic
acid) [poly(vinyl monomer)] in the particles was 43:57.
[0152] Synthesis of Labeled PLURONIC.RTM. L61
[0153] The DCTAF-labeled PLURONIC.RTM. L61 was synthesized and
purified essentially as described by Ahmed, F., et al., S.
Langmuir, 2001, 17, 537-546. Stock solutions of 6 w/v %
PLURONIC.RTM. L61 were prepared by dissolving the polymer in 0.1 M
sodium bicarbonate solution at pH=9.30. A stock solution of 20 g/L
5-DTAF was prepared by dissolving the fluorescein probe in dimethyl
sulfoxide (DMSO). The 5-DTAF solution was diluted in 0.1 M sodium
bicarbonate solution and added to the PLURONIC.RTM. block copolymer
solution such that the molar ratio of 5-DTAF to PLURONIC.RTM. was
1:1. The reaction was allowed to proceed in the dark at room
temperature overnight. To separate the labeled PLURONIC.RTM. from
the excess unreacted 5-DTAF, the size exclusion chromatography was
applied. Sephadex G-25 beads (Aldrich Chemical Co.) swollen in
boiling 0.05 M NaCl solution were first packed into a Chromaflex
column (ID, 2.5 cm, length, 60 cm) (Kimble/Kontes, Vineland, N.J.).
The column was then primed by washing with 0.05 M NaCl solution,
followed by passage of 1 bed volume of 6 w/v % unlabeled
PLURONIC.RTM. in sodium bicarbonate solution and 2-3 bed volumes of
0.05 M NaCl solution. A 250 .mu.L sample of the reaction mixture
was then added to the column, and the labeled product was eluted
with NaCl solution. The yellow bands moving down the length of the
column were separated and the PLURONIC.RTM.-containing fraction was
concentrated using a Centricon centrifugal filter device (Millipore
Corp., Bedford, Mass.) with a molecular weight cutoff of 1500. The
samples were centrifuged at ca. 5000.times.g for 1 h. The retentate
containing labeled PLURONIC.RTM. was lyophilized and kept at
-20.degree. C. in the dark. Given the dye molar extinction
coefficient of 83000 M.sup.-1 cm.sup.-1 and molecular weight of
495.3, the efficiency of the DCTAF dye conjugation with
PLURONIC.RTM. molecule was estimated to be 2.4-3.0%.
[0154] Solute Loading onto Microgels
[0155] The loading level of doxorubicin or PLURONIC.RTM. L61
labeled with DCTAF into microgels was measured using a Millipore
Ultrafree-MC Centrifugal Filter Device (Millipore Corp.). A
microgel was suspended in Tris buffer (10 mM, pH 7.0) and 1 mL of
the suspension (40 mg gel/mL buffer) were equilibrated with 6.0 mM
stock solution of a drug (9 mL) for 72 h while shaking. Shaking was
performed using a KS10 orbital shaker (BEA-Enprotech Corp., Hyde
Park, Mass.) in an environmental chamber at 37.degree. C. After
equilibration, the microgel particles were filtered off by
centrifugation (10000.times.g, 0.5 h) and supernatant was assayed
for drug concentration. A Shimadzu Model 1600 PC spectrophotometer
with a temperature-controlled quartz cuvette (path length 1 cm) was
used for electronic absorption measurements. The extinction
coefficients of doxorubicin (.lamda.=482 nm) was determined to be
12300 M.sup.-1 cm.sup.-1. Assuming the average molecular weight of
2000, the extinction coefficients of the DCTAF-labeled
PLURONIC.RTM. (.lamda.=492 nm) was measured at pH 7.0 to be 2600
M.sup.-1 cm.sup.-1. The drug uptake was calculated from the
absorbance readings in the appropriately diluted stock solution and
in the system equilibrated with microgel. The U values were
measured in triplicate for each drug and gel, respectively. In a
control series of experiments, equilibration of 24 .mu.mol/mL
doxorubicin with microgels for 1 week yielded U values close
(within experimental error) to the ones obtained with 6 .mu.mol/mL
solutions under otherwise identical conditions (see above). This
ensured equilibrium U values. The gels equilibrated with
corresponding drugs were snap-frozen in liquid nitrogen,
lyophilized, and stored at -70.degree. C. in the dark. In the
subsequent release studies, the dry gel powders of known U were
reconstituted with Tris buffer (10 mM, pH 7.0) to result in the
known concentration of the gel and drug.
[0156] Release Studies
[0157] Drug release from microgels loaded with either DCTAF-labeled
PLURONIC.RTM. or doxorubicin was studied using the dynamic dialysis
technique of Gupta, P. K., et al., J. Pharm. Sci., 1987, 76,
141-145. A Teflon-made, thermostatted dynamic dialyzer consisted of
two chambers, separated by a dialysis membrane (cellulose ester,
working area A=0.35 cm.sup.2, molecular weight cut-off 100 kDa,
Spectrum Laboratories). A cylindrical feed chamber (volume
V.sub.f=5.0 mL) containing drugs or drug-loaded gels was vigorously
stirred by a magnetic bar, while a receiver chamber had an inlet
and outlet for a constant flow of the receiver solution. The
receiver solution (Tris buffer, 10 mM, pH 7.0) was circulated along
the dialysis membrane using a P625/275 peristaltic pump (Instech
Laboratories). Concentration of the drug in the receiver solution
was monitored online by passing through a thermostatted quartz
cuvette (path length 1.0 cm). Concentration of solutes was measured
periodically using a Shimadzu Model RF-5301 PC
spectrofluorophotometer (slit widths 3.0 nm). The dialyzer was
maintained at 37.degree. C. by submersion in a water bath. The flow
rate through the receiver chamber was maintained at 1.5 mL/min. In
a series of preliminary experiments, it was established that at
this flow rate the doxorubicin transport becomes flow
rate-independent, and yet the flow of the PLURONIC.RTM. solution
affords avoiding any foaming. The total volume of the receiver
solution (V.sub.r), including the chamber, cuvette, and 0.093''
tubing, was 98 mL in all experiments.
[0158] Permeability of the dialysis membrane was determined by
loading a certain amount (q.sub.f.sup.0) of either doxorubicin or
PLURONIC.RTM. solution into the feed chamber and measuring the
kinetics of release. The dialysis membrane had been soaked in the
corresponding solute solution for 48 h prior to the kinetic
measurement. To remove excess solute, the membrane was gently wiped
up by a paper tissue on both sides immediately prior to the loading
into the dialyzer. The membrane thickness (.delta.) was measured
microscopically in the receiver solution upon completion of the
dialysis experiment and was typically in the order of 100 .mu.m.
Solving the 1.sup.st Fick's law expression for the diffusion across
the dialysis membrane Flux = d q r d t = D .times. A .function. ( C
f - C r ) .delta. ( 1 ) ##EQU2## yields an expression that allows
for an estimation of the apparent diffusion coefficient (D): ln
.left
brkt-bot.q.sub.f.sup.0-C.sub.r(V.sub.f+V.sub.r)=lnq.sub.f.sup.0-Kt
(2) where K=DA(V.sub.f+V.sub.r)/V.sub.fV.sub.r.delta. (3) Herein,
q(t) and C(t) are the drug quantity and concentration,
respectively, and subscripts f and r designate the feed and
receiver solution, respectively.
[0159] Having defined the ranges of concentrations where the
diffusion coefficient of either doxorubicin or PLURONIC.RTM. was
independent of the drug initial concentration C.sub.f.sup.0, we
used the microgel loading that did not exceed these ranges. A known
mass of microgel particles with a known loading (U, see above)
suspended in 10 mM Tris buffer (pH 7.0) was placed in the feed
chamber resulting in an initial drug quantity in the system,
Q.sub.o. Assuming that the drug decay in the microgel particles can
be approximated by a single-exponential (i.e., first-order)
kinetics Q(t)=Q.sub.oe.sup.-K.sup.1.sup.t, the Fick's law
expression (1) can be rewritten as Flux = d C r d t = DA .delta.
.times. .times. V r .function. [ Q 0 V f .times. ( 1 - e - K 1
.times. t ) - C r .function. ( V r V f + 1 ) ] ( 4 ) ##EQU3## and
solved with respect to C.sub.r as follows: C r = .times. Q 0 V f +
V r [ 1 - e - Kt - DA .function. ( V f + V r ) .delta. .times.
.times. V f .times. V r .function. ( K - K 1 ) .times. e - Kt -
.times. DA .function. ( V f + V r ) .delta. .times. .times. V f
.times. V r .function. ( K - K 1 ) .times. e - K 1 .times. t ] ( 5
) ##EQU4##
[0160] At long dialysis times and Kt>>K.sub.1t, eq(5) can be
simplified: ln .function. [ Q 0 V f + V r - C r ] = ln .function. [
DAQ 0 .delta. .times. .times. V f .times. V r .function. ( K - K 1
) ] - K 1 .times. t ( 6 ) ##EQU5## Equation (6) indicates that a
plot of ln [Q.sub.o/(V.sub.f+V.sub.r)-C.sub.r] vs time should be a
straight line that yields K.sub.1. We used equations (2) and (3) to
calculate the permeability of the dialysis membrane in experiments
without microgels, and equation (6) to estimate K.sub.1 in
experiments with drug-loaded microgels.
[0161] Results
[0162] Kinetics of the release of doxorubicin and PLURONIC.RTM. L61
through dialysis membrane with and without microgels are compared
in FIG. 5 (Kinetics of cumulative release of doxorubicin (circles)
and PLURONIC.RTM. L61 (triangles) through the dialysis membrane
with (filled points) and without (open points) microgels in the
feed chamber at 37.degree. C. Receiver chamber comprised 10 mM Tris
buffer (pH 7.0) in all cases. Initial doxorubicin concentration in
the feed 110 .mu.g/mL (open circles) and 20 mg/mL (filled circles),
initial PLURONIC.RTM. L61 concentration in the feed 20 mg/mL (open
triangles) and 22 mg/mL (filled triangles). Microgels used in the
feed were composed of PLURONIC.RTM. F127 and poly(acrylic
acid)).
[0163] As shown in FIG. 5, loading of the corresponding drugs into
microgels affected the kinetics of release greatly. Without
microgels, almost 100% of the drug was released within less than a
day, while the drugs loaded into microgels exhibited slow,
sustained release kinetics.
[0164] In the control experiments, we measured permeability of the
dialysis membrane for doxorubicin and PLURONIC.RTM. L61 without
loading into microgels. A range of initial drug concentrations in
the feed solutions was explored, in order to verify the
independence of the effective membrane permeability of the
q.sub.f.sup.0, as is required if the change of the solute size
(i.e. aggregation and/or micellization) is absent. FIG. 6
illustrates kinetics of the drug diffusion through the dialysis
membrane as functions of the initial drug concentrations in the
feed. The effective membrane permeability constant, K, was found
from the slopes of the corresponding linear fits using equation
(2). Thus obtained K values were equal to 0.70.+-.0.048(4) and
0.41.+-.0.019(3) h.sup.-1 .mu.g.sup.-1 for doxorubicin and
PLURONIC.RTM. L61, respectively. Given very close K values
(standard error below 7% and 5% for doxorubicin and PLURONIC.RTM.
L61, respectively) obtained within the studied ranges of
C.sub.f.sup.0 we concluded that aggregation was absent within those
ranges. Using mean K and measured membrane thickness (.delta.)
values, we obtained the effective diffusion coefficients (D) of
2.4.times.10.sup.-5 and 1.4.times.10.sup.-5 cm.sup.2/s for
doxorubicin and PLURONIC.RTM. L61, respectively (eqn (3)). These
values are reasonably close to D of the corresponding solutes in
water, indicating that the chosen dialysis membrane does not
constitute any significant diffusional barrier to these solutes in
their non-aggregated state. FIG. 6 shows the kinetics of
doxorubicin and PLURONIC.RTM. L61 release through the dialysis
membrane from an aqueous feed solution at 37.degree. C., expressed
in terms of equation (2). Numbers stand for C.sub.f.sup.0,
.mu.g/mL. Corresponding linear fits (R.sup.2>0.99 in all cases)
were used to calculate (eqn(2)) the effective membrane permeability
constant, K.
[0165] Having defined the membrane permeability, we proceeded to
the drug release study from the microgels. Kinetics of doxorubicin
release from the microgels are shown in FIG. 7. The effective
release constants (K.sub.1) for doxorubicin were measured to be
(14.2.+-.0.36).times.10.sup.-3 and (22.8.+-.0.49).times.10.sup.-3
h.sup.-1 .mu.g.sup.-1 for microgels based on PLURONIC.RTM.
F127-PAA-EGDMA and PLURONIC.RTM. L92-PAA-EGDMA, respectively. FIG.
7 shows the kinetics of doxorubicin release through the dialysis
membrane from microgels at 37.degree. C., expressed in terms of
equation (6). Numbers stand for C.sub.f.sup.0 in .mu.g/mL. The
datapoints were fitted to linear fits (R.sup.2>0.98 in all
cases) with the slopes used to calculate (eqn(6)) the effective
release constant, K.sub.1. In A, the gels used in feed consisted of
PLURONIC.RTM. F127 and PAA, whereas in B, the gels consisted of
PLURONIC.RTM. L92 and PAA. The effective degree of the gel
cross-linking was 1 mol % throughout.
[0166] Kinetics of PLURONIC.RTM. L61 release are presented in FIG.
8 which shows the release through the dialysis membrane from
microgels at 37.degree. C., expressed in terms of equation (6).
Numbers stand for C.sub.f.sup.0 in .mu.g/mL. The datapoints were
fitted to linear fits (R.sup.2>0.97 in all cases) with the
slopes used to calculate (eqn(6)) the effective release constant,
K.sub.1. In A, the gels used in feed consisted of PLURONIC.RTM.
F127 and PAA, whereas in B, the gels consisted of PLURONIC.RTM. L92
and PAA. The effective degree of the gel cross-linking was 1 mol %
throughout.
[0167] The effective release constants (K.sub.1) for the
PLURONIC.RTM. were measured to be (2.1.+-.0.18).times.10.sup.-3 and
(0.44.+-.0.046).times.10.sup.-3 h.sup.-1 .mu.g.sup.-1 for microgels
based on PLURONIC.RTM. F127-PAA-EGDMA and PLURONIC.RTM.
L92-PAA-EGDMA, respectively. FIG. 8 shows that a very slow,
sustained release of the PLURONIC L61.RTM. was achieved within at
least 10 days, with cumulative concentrations reached in the
receiver solution (C.sub.r) that did not exceed 10-14% of the
initial loading, C.sub.f.sup.0. The exceptionally low release rate
of the PLURONIC.RTM. L61 can be explained by the formation of mixed
micelles between added PLURONIC.RTM. L61 and PLURONIC.RTM.
covalently grafted to the PAA network in the process of synthesis.
Such mixed, immobile micelles can provide thermodynamically stable
environment for the PLURONIC.RTM. solute, making its effective
partition coefficient between micelles and water to be very low.
This notion is supported by the observation that the release rate
from the gels from L92-PAA-EGDMA was about 5-fold higher than from
the gels containing PLURONIC.RTM. F127 bonded to PAA. Formation of
stable mixed micelles between relatively hydrophobic PLURONIC.RTM.
L61 and L92 can be favored than between PLURONIC.RTM. L61 and
relatively hydrophilic F127 (for PLURONIC.RTM. properties, see
Table 1, supra).
Example II
Microgel Synthesis
[0168] Nonionic copolymer PLURONIC.RTM. F127 NF was obtained from
BASF Corp. and used without further treatment. It has a formula
EO.sub.100PO.sub.65EO.sub.100, nominal molecular weight 12600,
molecular weight of PPO segment 3780, 70 wt % of EO, and cloud
point above 100oC. Acrylic acid (99%) (vinyl monomer), ethylene
glycol dimethacrylate (EGDMA) (98%) (divinyl cross-linker),
dodecane (99+%) (solvent), and 4,4'-azobis(4-cyanovaleric acid)
(75+%) (azo initiator) were purchased from Aldrich Chemical Co. and
used as received. Lauroyl peroxide (97%) (redox initiator) was
obtained from Fluka Chemie AG, Switzerland.
Poly(vinylpyrrolidinone-co-1-hexadecene) (Ganex V-216) (dispersion
stabilizer) was obtained from International Specialty Products and
used as received. All other chemicals, gases and organic solvents
of the highest purity available were obtained from commercial
sources.
[0169] Synthesis was carried out on a laboratory scale in an
adiabatic mode. Acrylic acid (vinyl monomer) (40 mL) was partially
neutralized by addition of 5M NaOH aqueous solution (0.5 mL).
PLURONIC.RTM. F127 NF (23.4 g) was dissolved in the resulting
solution under nitrogen and a desired amount of ethylene glycol
dimethacrylate (EGDMA) (divinyl cross-linker) was added. Amounts of
EGDMA ranged from 1.1 .mu.L to 1.1 mL and the molar ratio of the
EGDMA to acrylic acid set in the reaction mixture designates the
degree of cross-linking of the microgels in what follows. Lauroyl
peroxide (100 mg) and 4,4'-azobis(4-cyanovaleric acid) (100 mg)
were dissolved in 2 mL of acrylic acid and added to the solution of
PLURONIC.RTM. F127 NF in acrylic acid. The resulting solution was
deaerated by nitrogen bubbling for 0.5 h and added to a 3-necked
0.5-mL flask containing 1 wt % solution of Ganex V-216 in dodecane
(200 mL). The flask was vigorously stirred by a mechanical stirrer
and deaerated by constant nitrogen purge from the bottom. Then the
flask was heated to 70.degree. C. using an oil bath and kept at
that temperature under stirring and nitrogen purge. After about 1
h, formation of white particles was observed on the flask walls.
The reaction was continued at 70.degree. C. for another 3 h. Then
the reactor was disassembled, and the contents of the reactor were
filtered using Whatman filter paper (retention size 10 micron). The
microgel particles were extensively washed by hexane and dried
under vacuum.
[0170] Spherical particles were observed under microscope. Particle
sizing was performed in hexane using a ZetaPlus Zeta Potential
Analyzer (Brookhaven Instruments Co.). A typical batch containing 1
mol % cross-linking was measured to have effective
Example III
Microgel Superabsorbent Properties
[0171] The ability of microgels to absorb water was estimated using
a volumetric method. Single microgel particles were placed into
glass capillary tubes (internal diameter 1-1.2 mm) using suction
pressures applied by an Ultramicro Accropet filler/dispenser via
rubber connector. The tubes were placed into a homemade glass
thermostatted cuvet and observed under an inverted microscope
equipped with a microscaler and a video monitor. Similar
experimental setup was described in Eichenbaum, G. M., et al.,
Macromolecules, 1998, 31, 5084-5093. The boundaries of the
spherical particles were fitted with the microscaler and a particle
diameter was measured with an accuracy of .+-.0.5 .mu.m or better.
Initially, a diameter of a dry particle (d.sub.o) was measured,
then the capillary tube was gently filled with deionized water (pH
adjusted by 5 M NaOH) immersed into a reservoir of the same
solution. The diameter of the swollen particle (d.sub.s) was
measured at a given temperature. The particles were allowed to
swell for 24 h, after which no changes in the particle size were
observed at any temperature. The equilibrium volume ratio
S=V/V.sub.o was defined as S=(d.sub.s/d.sub.o).sup.3. Measurements
at given pH and temperature were conducted with 5 different
particles in different capillary tubes. Average S values are
reported throughout.
[0172] The results of equilibrium swelling experiments with
microgels cross-linked by EGDMA are shown in FIG. 9. The length of
subchain (i.e. length of the chain between cross-links) N defined
as in Bromberg, L., et al., J. Chem. Phys., 1997, 106, 2906-2910.
N=[a.sup.6c.sub.xl(c.sub.xl+c.sub.m)].sup.-1 where
a=10v.sub.xlv.sub.m, v.sub.xl=0.2 M.sup.-1 is the molar volume of
the cross-linker (EGDMA), and v.sub.m=0.063 M.sup.-1 is the molar
volume of the monomer (acrylic acid).
[0173] FIG. 9. Equilibrium swelling of microgel particles in
deionized water as a function of the length of subchain. pH 7.0.
The results shown in FIG. 9 indicate that at 15.degree. C.,
swelling of the microgels corresponds to the swelling of other
superabsorbents and is governed by elasticity of the permanent
cross-links and osmotic term corresponding to the electrostatic
repulsion of the chains. At 15.degree. C., the swelling ratio S
scales as S.varies.N.sup.0.6, which according to the Flory-Huggins
theory is indicative of the Gaussian chain statistics, typical for
covalently cross-linked gels. However, at 37.degree. C., elasticity
of the microgel becomes higher due to the appearance of additional
cross-links (PLURONIC.RTM. chains with hydrophobic poly(ethylene
oxide) segments). The swelling ratio scales as S.varies.N.sup.x,
with x<0.6 meaning non-Gaussian chain statistics. Overall, the
results in FIG. 9 show i) high absorbency (swelling ratio in DI
water up to 300 and higher), and ii) useful temperature sensitivity
of water uptake.
Example IV
pH-Sensitivity of Microgel Swelling
[0174] Experiments were conducted as described in Example III,
except the microgel particles were allowed to equilibrium swell at
a certain pH.sub.o and temperature to yield a d.sub.o. Then the
aqueous solution was gently removed from the glass tube by filter
paper and the tube with the microgel particle was immersed into a
solution of different pH.sub.x and equilibrated there overnight.
Finally, the tube with the microgel particle filled with the
solution of pH.sub.x was inserted into the cuvet and thermostatted
at desired temperature to yield an equilibrium microgel diameter
d.sub.x. The equilibrium volume ratio S=V.sub.x/V.sub.o was defined
as S=(d.sub.x/d.sub.o).sup.3. FIG. 10 shows quilibrium swelling of
microgel particles in deionized water at 15.degree. and 37.degree.
C. as a function of pH. Degree of cross-linking in molar percent is
indicated. Results in FIG. 10 show dramatic increase in swelling
above pH 3.8-4.1, corresponding to pKa of poly(acrylic acid).
Hence, our microgels would be collapsed at pH 1-2 and fully swollen
at pH 7.4. This is a useful property applicable in oral or colonic
drug delivery.
Example V
Temperature-Sensitivity of Microgel Swelling
[0175] Experiments were conducted as described in Example IV and
the results are shown in FIG. 11 illustrating equilibrium swelling
of microgel particles in deionized water at pH 7.0 as a function of
temperature. Degree of cross-linking in molar percent is indicated.
These results demonstrate useful temperature-sensitivity of the
microgel swelling.
Example VI
Temperature-Sensitivity of Solubilization of Hydrophobic
Compounds
[0176] Solubilization of pyrene, a well-known hydrophobic
fluorescent probe, was used to reveal formation of aggregates
within microgel particles capable of solubilizing hydrophobic
compounds. The microgel particles were suspended in DI water and pH
of the suspension was adjusted to 7.0 using 10 M NaOH. A stock
solution of 1 mM pyrene in absolute methanol was prepared, from
which 1-3 .mu.L were added to an aerated 1 wt % suspension
resulting in 0.6 .mu.M pyrene concentration. The sample was then
allowed to equilibrate for 20 min at a given temperature and
emission (.mu..sub.ex=335 nm) spectra were recorded using a
stirred, thermostatted quartz cell with a 1-cm path length. The
spectra were measured under controlled temperature conditions using
a Shimadzu Model RF-5301 PC spectrofluorophotometer (slit widths of
1.5 nm). The ratio of the intensities of the first (373 nm) to the
third (384 nm) vibronic peak (I.sub.1/I.sub.3) in the emission
spectra of the monomer pyrene were used to estimate the polarity of
the pyrene microenvironment. For comparison, 1 wt % solutions of
PLURONIC.RTM. F 127 NF were prepared and studied in the same
fashion. The effect of temperature on I.sub.1/I.sub.3 of pyrene in
microgel suspension (1 mol % cross-linking) or in polymer solutions
is presented in FIG. 12. FIG. 12 shows the effect of temperature on
the ratio of the first-to-the-third vibronic band intensities
(I.sub.1/I.sub.3) of pyrene in 1 wt % microgel suspension or in 1
wt % PLURONIC.RTM. F127 solution. Microgel with 1 mol %
cross-linking is designated F127-PAA-EGDMA. pH 7.0 throughout. As
is seen, in 1.0% PLURONIC.RTM. F127 solutions, for example, the
I.sub.1/I.sub.3 sharply declines above 20.degree. C., which is the
critical micellization temperature (CMT). Alexandridis, P., et al.,
J. Am. Oil Chem. Soc. 1995, 72, 823. At temperatures below CMT, the
I.sub.1/I.sub.3 is only slightly below the I1/I3 in water,
indicating high polarity of the pyrene environment and lack of
solubilization. The microgel suspension has I1/I3 values that are
significantly less than in the corresponding Pluronic solution,
indicating lesser polarity and higher capability of solubilization
throughout the temperature range. The I1/I3 in microgel suspension
is low at T<20.degree. C. (which corresponds to the critical
micellization temperature of PLURONIC.RTM.) and increases in the
temperature range 20-26.degree. C. Above 26.degree. C., the
I.sub.1/I.sub.3 decreases. At low temperatures, hydrophobic domains
exist in the microgels that are getting solubilized into
hydrophobic micelle-like aggregates of Pluronic within microgels.
Once micelles are formed above 26.degree. C., they provide a
hydrophobic environment for the pyrene. The temperature-responsive
mode of solute solubilization by microgels is useful for medicinal
and cosmetic formulations.
Example VII
Loading of Ionic and Hydrophobic Drugs
[0177] Water-Soluble Solutes
[0178] The maximum loading level of doxorubicin, mitoxantrone, and
mitomycin C, for example, into microgels was measured using a
Millipore Ultrafree-MC Centrifugal Filter Device (Millipore, Co.).
A microgel was suspended in Tris buffer (5 mM, pH 7.0) and 50 .mu.L
of the suspension (2 mg gel/mL buffer) was equilibrated with 3.0 mM
stock solution of a drug (450 .mu.L) for 16 h while shaking 44, 45.
Shaking was performed using a KS 10 orbital shaker (BEA-Enprotech
Corp., Hyde Park, Mass.) in an environmental chamber at 37.degree.
C. In the case of doxorubicin, pH of the microgel suspensions
equilibrated with the stock drug solution was varied by addition of
small amounts of 5 M NaOH or HCl solutions, and temperature was
varied from 15 to 45.degree. C. After equilibration, the microgel
particles were filtered off by centrifugation (10000.times.g, 0.5
h) and supernatant was assayed for drug concentration. A Shimadzu
Model 1600 PC spectrophotometer with a temperature-controlled
quartz quvette (path length 1 cm) was used for electronic
absorption measurements. The extinction coefficients of doxorubicin
(.lamda.=482 nm) and mitoxantrone (.lamda.=614 nm) were determined
at pH 7.0 to be 12200 and 22100 M.sup.-1 cm.sup.-1, respectively.
The concentration of mitomycin C was assayed by HPLC using a
Capcell Pak MF Ph-1 (100.times.4.6 mm I.D., particle size 5 .mu.m)
column (Phenomenex, Torrance, Calif.). The HPLC was a
Hewlett-Packard 1090 system with an autosampler and a variable
wavelength UV detector controlled by the HPLC Chemstation software
(Hewlett-Packard). Deionized water was used as a mobile phase (flow
rate, 1 mL/min, injection volume, 25 .mu.L), and detection was
carried out at 365 nm 47. Typical retention time of the mitomycin C
was 4.88 min.
[0179] The drug uptake was expressed as:
[0180] U (mmol drug/g gel)=[(Ac-Ar)/Ac]VCs/Mgel, where Ac and Ar
are the absorbance or HPLC readings in the appropriately diluted
stock solution and in the system equilibrated with microgel,
respectively, V=0.5 ml is the total volume of the system, Cs=3
.mu.mol/mL is the concentration of the stock solution, and Mgel=0.1
mg is the microgel mass. The U values were measured in triplicate
for each drug and for each temperature, pH, and gel, respectively.
In a control series of experiments, equilibration of 6 .mu.mol/mL
doxorubicin with microgels for 1 week yielded U values close
(within experimental error) to the ones obtained with 3 .mu.mol/mL
solutions under otherwise identical conditions. This ensured
equilibrium U values.
[0181] Hydrophobic Solutes
[0182] The loading of taxol into microgels was measured by
equilibrating taxol adsorbed onto steel beads with the 1 wt %
suspension of microgels (pH 7.0). Stainless steel beads (1-3 mm
diameter) were soaked in 10 mM solution of taxol in acetonitrile,
following by stripping off the solvent in a rotary evaporator. The
beads were used in order to enhance the area of contact between
microgel suspension and taxol. The beads were separated into
several fractions. One fraction was added to a polypropylene vial
containing the microgel suspension (0.5 mL) and the vial was gently
shaken in a horizontal position in an environmental chamber at 20
or 37.degree. C. Then the beads were recovered from the suspension
by using a magnet. The beads were then dried under vacuum and
placed into acetonitrile (0.5 mL), where taxol was extracted after
shaking overnight. The solvent fraction was assayed for taxol
concentration using HPLC. The control fraction of loaded beads was
subjected to the extraction without equilibration with the microgel
suspension. The solubility of taxol in water was measured at
37.degree. C. by sonicating 5 mg of the drug suspension in 0.5 ml
water placed in a polypropylene vial for 15 s followed by
centrifugation at 10000 g for 3 min. The supernatant was then
removed, evaporated under vacuum, the taxol traces were dissolved
in acetonitrile and assayed by HPLC. Taxol concentrations were
measured in triplicate using HPLC system described above. The
chromatography assay comprised the use of a Capcell Pak C18 UG 120
(150.times.4.6 mm I.D., particle size 3 .mu.m) column (Phenomenex),
acetonitrile-0.1% phosphoric acid in DI water (55:45 v/v, 1.3
mL/min) as a mobile phase, and UV detection at 227 nm.
[0183] Typical retention time of the taxol peak was 3.46 min.
[0184] Results
[0185] Three cationic and one uncharged drugs were loaded onto the
microgels. All of these compounds are currently in clinical use as
anticancer drugs. Doxorubicin, mitoxantrone, and mitomycin C are
mono-, di-, and trivalent cationic weak bases, respectively. FIG.
13 shows the equilibrium uptake of doxorubicin by microgels
(crosslinking (XL)=1 mol %) as a function of pH at 37.degree.
C.
[0186] Table 2 lists molecular weights, n-octanol-to-water
partition coefficients (P), and equilibrium uptake of the drugs
into the microgels characterized by XL=1 mol % and maximum
ion-exchange capacity of 6.12 mmol/g (measured by bulk titration as
described herein). All of the uptake values in Table 2 were less
than or equal to maximum microgel capacity for protons. A
pronounced dependence was observed with the weak bases: the
smaller, more hydrophilic, and more charged solutes had the higher
loading into the microgels. TABLE-US-00006 TABLE 2 Properties of
anticancer drugs and their equilibrium uptake by the PLURONIC
.RTM.-PAA microgels (cross-linking ratio, XL = 1 mol %,
ion-exchange capacity, 6.12 mmol/g) at pH 7.0. Drug MW .sup.a Log P
Charge Uptake .+-. SD, mmol/g Mitomycin C 334.1 -0.4 3 5.31 .+-.
1.86 (37.degree. C.) Mitoxantrone 444.2 .sup. 0.24 .sup.b 2 3.70
.+-. 0.56 (37.degree. C.) Doxorubicin 543.5 1.85 1 2.97 .+-. 0.33
(20.degree. C.) 2.26 .+-. 0.37 (37.degree. C.) Taxol 853.3 4 0
(2.27 .+-. 0.90) .times. 10'.sup.-3 (20.degree. C.) (6.97 .+-.
0.87) .times. 10'.sup.-3 (37.degree. C.) .sup.a Molecular weights
are given for free bases, and not hydrochloride salts. .sup.b
Calculated using ClogP Program.
[0187] The characteristic increase in taxol loading capacity at
temperatures above CMT provides additional evidence to the
mechanism of taxol solubilization into micelle-like aggregates
within microgels. The micelles in PLURONIC.RTM.-PAA solutions
typically have solubilizing capacity higher than the small
hydrophobic domains existing below CMT. The solubilizing capacity
of the microgels for taxol is at least equal to that of
PLURONIC.RTM.-PAA micelles for other hydrophobic solutes such as
steroid hormones. The ability of microgels to effectively load and
hold taxol, combined with mucoadhesive properties is a feature
important for localized delivery.
[0188] General trends important for drug loading via ion-exchange
mechanism were studied using the potent chemotherapeutic drug
doxorubicin. As the degree of carboxyl group ionization increases
with pH, the ion-exchange capacity of the microgels increase,
reaching about half of the maximum capacity found by titration,
indicating that the loading of doxorubicin can be limited by the
available free volume of the network. Notably, the pH-dependencies
of the equilibrium swelling and doxorubicin loading coincide.
Similar result was observed with poly(methacrylic acid) microgels.
The effects of steric "crowding" of the drug within the microgel
network and the availability of the carboxyls for the ion-exchange
are highlighted by the effects of temperature and cross-linking
density. The collapse of the microgels at elevated temperature due
to the appearance of physical cross-links leads to lesser volume of
the microgel network available for hosting the drug, and thus lower
equilibrium loading at higher temperatures. Analogously, the longer
subchain allowing for the looser network and higher swelling leads
to the higher equilibrium loading of doxorubicin. The very high
overall capacity of the microgels for doxorubicin (2 M and higher),
will allow proper chemotherapeutic drug delivery. Microgels loaded
with both taxol and doxorubicin, for example, is a feature
embodiment of the microgels described herein.
Example VIII
Doxorubicin Transport Study Across Gastrointestinal Caco-2 Layers
Materials and Cell Culture
[0189] Caco-2 cells (American Type Culture Collection, Rockville,
Md.) were maintained at 37.degree. in Dulbecco's Modified Eagle
Medium (DMEM) containing
N-(2-hydroxyethyl)piperazine-N'-(2-ethanesulfonic acid) (HEPES, 25
mM), glucose (4.5 g/L), and supplemented with 10% (v/v) fetal
bovine serum, 1% nonessential amino acids, L-glutamine (2 mM),
penicillin (100000 U/L), and streptomycin (100 mg/L), in an
atmosphere of 10% CO.sub.2 and 90% relative humidity. The cell line
(passage numbers from 70 to 85) was subcultured by trypsinization
every week and the medium was replaced every other week. Cells were
passaged at 90% confluency using a 0.25% trypsin/0.20% ethylene
diamine tetraacetic acid (EDTA) solution. All cell culture products
were received from GIBCO.TM. (Invitrogen Corporation, Carlsbad,
Calif.). Hank's balanced salt solution (HBSS, composition:
KH.sub.2PO.sub.4, 0.44 mM; KCl, 5.37 mM; Na.sub.2HPO.sub.4, 0.34
mM; NaCl, 136.9 mM; D-glucose 5.55 mM) buffered with 30 mM HEPES at
pH 7.2, 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium
bromide, and Verapamil were obtained from Sigma Chemical Co. (St.
Louis, Mo.). D-[1-.sup.14C]-mannitol (250 mCi/mmol, 99+%
radiochemical purity, MW 182.2) was obtained from PerkinElmer Life
Sciences (Boston, Mass.). Carbopol.RTM. 934 NF polymer was received
from Noveon, Inc. (Cleveland, Ohio). Microgels comprising
copolymers of poly(acrylic acid) and Pluronic F127 NF or Pluronic
L92 cross-linked by ethylene glycol dimethacrylate at effective
cross-linking density of 0.1 mol % were synthesized by a
free-radical suspension polymerization as described previously [9].
The microgels were purified from admixtures of acrylic acid and
unattached Pluronic by Soxhlet extraction and dialysis [9]. The
purified microgels were analyzed for residual unattached Pluronic
as follows. A microgel suspension (10 wt %, 50 g) in deionized
water was dialyzed for a week at 4.degree. C. against deionized
water (0.5 L) using a Spectra/Por.RTM. cellulose ester membrane
(molecular weight cut-off 100,000, Spectrum.RTM., Laguna Hills,
Calif.). Then the dialysis bag was withdrawn and the dialyzate was
lyophilized to dryness in 40-mL polypropylene tubes. Then the tubes
were rinsed, with brief sonication, with total of 5 mL
dimethylformamide, thereby concentrating the wash-outs, if any,
100-fold. The wash-outs were analyzed for the presence of Pluronic
using HPLC. Liquid chromatography was performed using a
Hewlett-Packard model 1050 chromatograph, a Dynamax model RI-1
analytical refractive index detector, and two PLgel 5 .mu.m mixed
`D` columns in series. The analyses of the residual solids were run
in DMF at 1.0 mL/min flow rate using poly(ethylene glycol)
standards kit (Polysciences, Inc., Warrington, Pa.) for molecular
weight calibration. The eluent was DMF (HPLC grade) at a flow rate
of 1 mL min.sup.-1. In the control assays, a 20 .mu.g/mL
concentration or lower of either Pluronic F127 or L92 could be
detected. However, no Pluronic could be detected in the wash-outs,
which means that the concentration of the unattached Pluronic was
less than 0.01 wt % of the total Pluronic bonded onto microgels.
The weight ratio of Pluronic to poly(acrylic acid) in purified
microgels used in this study was determined as described elsewhere
[7] to be 45:55. The microgels equilibrium swollen in deionized
water (pH adjusted to 7.0) were subjected to particle sizing using
an AccuSizer 780/SPOS (Christison Scientific Equipment Ltd.,
Gateshead, UK). The mean populations of the F127-PAA-EGDMA and
L92-PAA-EGDMA microgels were of 54.+-.22 and 23.+-.9 .mu.m size,
respectively.
[0190] Transepithelial Transport of Doxorubicin
[0191] The drug-containing samples for the transport experiments
were prepared as follows. A freeze-dried microgel was autoclaved at
121.degree. C. for 15 min and suspended in serum-free DMEM, where
it was allowed to equilibrate at 37.degree. C. under gentle
stirring overnight in sterile conditions. The suspension was
centrifuged at 8000.times.g for 0.5 h and the supernatant was
removed. The pellet was weighed and resuspended in fresh portion of
serum-free DMEM of a known weight. Known amount of doxorubicin and
Pluronic were dissolved in the suspension, which was allowed to
equilibrate at 37.degree. C. overnight, then snap-frozen and
lyophilized. The powders were kept at -70.degree. C. Before the
transport experiments, a known amount of powder was reconstituted
in DMEM and was allowed to equilibrate at 37.degree. C. overnight.
The composition of the drug-containing samples tested in the
transport experiments is given in Table 3. TABLE-US-00007 TABLE 3
Composition of the drug-containing donor media used in
transepithelial transport experiments in the apical or basolateral
compartments. .sup.a Microgel Concentration of additive Microgel
concentration, (beyond doxorubicin), No. composition .sup.b
.mu.g/mL .mu.g/mL .sup.c 1 None (Control) 0 None 2 None 0 100
(Pluronic L61) 0 (Verapamil) 3 None 0 100 (Pluronic L92) 0
(Verapamil) 4 L92-PAA-EGDMA 100 None 5 L92-PAA-EGDMA 100 100
(Pluronic L61) 0 (Verapamil) 6 L92-PAA-EGDMA 100 100 (Pluronic L92)
0 (Verapamil) 7 F127-PAA-EGDMA 100 0 8 F127-PAA-EGDMA 100 100
(Pluronic L61) 0 (Verapamil) 9 F127-PAA-EGDMA 100 100 (Pluronic
L92) 0 (Verapamil) 10 None 0 0 (Pluronic) 9 (Verapamil) 11
L92-PAA-EGDMA 100 0 (Pluronic) 9 (Verapamil) 12 F127-PAA-EGDMA 100
0 (Pluronic) 9 (Verapamil) .sup.a Initial concentration of
doxorubicin in the donor compartment was 100 .mu.g/mL in all
experiments .sup.b Degree of cross-linking, XL = 0.1 mol %
throughout .sup.c Concentrations of added Pluronic L61 and L92 were
arbitrarily chosen to result in effective Pluronic concentrations
just below CMC [40, 41]. Concentration of added Verapamil was 20
.mu.M [27].
[0192] Cells were seeded at a density of (2-4).times.10.sup.4
cells/cm.sup.2 on top of Transwell.TM. polycarbonate filters (pore
size, 0.4 .mu.m; diameter, 24.5 mm; growth area, 4.71 cm.sup.2)
from Costar (Cambridge, Mass.). The cells were grown for 3 weeks
prior to the transport experiments and trans-epithelial electrical
resistance (TEER) was measured using a Millicell-ERS device
(Millipore, Bedford, Mass.) equipped with rod-shaped electrodes.
The TEER data were corrected for background readings contributed by
the blank filter and culture medium. Typical values of TEER were
800-850 .OMEGA.cm.sup.2. Then the monolayers were rinsed twice by
serum-free DMEM and the transport experiment commenced by replacing
the medium at either the basolateral or the apical side of the
monolayer with 2.5 mL of the serum-free DMEM containing doxorubicin
(with or without microgels, see Table 3). Simultaneously, the
medium on the other side was refreshed. The monolayers were
incubated at 37.degree. C. in 10% CO.sub.2 atmosphere. Samples of
200 .mu.L were taken from each side intermittently, and the drug
concentration was measured in the samples withdrawn from the side
opposite to the side of the drug application. The volumes withdrawn
were immediately replaced with equal volumes of serum-free DMEM
pre-equilibrated at 37.degree. C. Each experiment was repeated four
times. The TEER values were measured after the completion of each
transport experiment and were shown to be equal to the initial TEER
values obtained prior to the commencement of the experiment. The
doxorubicin concentration was assayed using a Shimadzu Model
RF-5301 PC spectrofluorophotometer (.lamda..sub.excitation 480 nm,
.lamda..sub.emission 580 nm). Additionally, the concentration of
doxorubicin in the medium was measured by HPLC using a Capcell Pak
UG C18 (100.times.4.6 mm I.D., particle size 5 .mu.m) column and a
Universal Guard Cartridge System (Phenomenex, Torrance, Calif.).
The HPLC was a Hewlett-Packard 1090 system with an autosampler and
a ZETALIF laser induced fluorescence detector (ESA, Inc.,
Chelmsford, Mass.). Water/acetonitrile (70/30, pH 4) was used as
the mobile phase (flow rate, 1 mL/min, injection volume, 5 .mu.L),
and detection was carried out using an Argon Ion laser (488 nm, 10
mW). Surface tension in microgel suspensions was measured using the
Wilhelmy plate method (Sigma 701 automatic tensiometer, KSV
Instruments, Ltd.). Temperature was controlled to .+-.0.05 C using
a circulating water bath. The platinum Wilhelmy plate was washed
with acetone, rinsed in Milli-Q water, and flamed until red-hot
before each measurement.
[0193] The apparent permeability of the Caco-2 monolayer (P.sub.a,
cm/s) was calculated from the linearized time course of the
doxorubicin fractional transport (dI.sub.1t/dt in the fluorescence
assay and dC.sub.t/dt in the HPLC assay) normalized to the
effective surface area of the filter (A=4.71 cm.sup.2) and the
initial fluorescence emission intensity reading (I.sub.o) or
initial doxorubicin concentration (C.sub.o) in the donor
(basolateral or apical) compartment of volume V=2.5 cm.sup.3: P a =
d I t / d t AI 0 .times. V = d C t / d t AC 0 .times. V ##EQU6##
Excellent correlation was obtained between permeability values
determined via fluorescence and HPLC assay (FIG. 14).
[0194] Transport Via Paracellular Route
[0195] The effect of microgel addition on paracellular permeability
of the Caco-2 cell layers was estimated via permeability of
mannitol, a neutral molecule, which is absorbed exclusively by
passive diffusion through the paracellular route [42].
[0196] To attenuate the effect of PAA on the transepithelial
transport, the experiments were conducted in calcium- and
magnesium-free HBSS. Prior to the commencement of the transport
experiments, the culture DMEM was replaced with an equal volume of
HBSS and the cells were allowed to equilibrate for 1 h. Donor
suspensions (2.5 mL total) containing 0.1 or 0.5 mg/mL microgels or
Carbopol 934NF pre-equilibrated with .sup.14C-mannitol in HBSS
(initial specific activity of 0.2 .mu.Ci/mL) were used to replace
the HBSS on the apical side, and the experiment commenced after 10
min of initial equilibration. Permeability experiments were
conducted at pH 7.2, 37.degree. C., 5% CO.sub.2, and 90% relative
humidity The TEER was measured following equilibration as described
above for doxorubicin transport. TEER measurements were also
performed during the experiment with 0.5 mg/mL polymer loading in
order to check the effect of polymers on the opening, if any, of
the tight intercellular junctions at time intervals of 0 (i.e. 10
min after adding the polymers), 30, 60, 90, 120, 150, 180, 210, and
240 min. The samples withdrawn prior to the 30-min time interval
were not included in the P.sub.m calculation to ensure steady-state
kinetics. The withdrawn samples of .sup.14C-mannitol were mixed
with 3 ml of MicroScint.TM. scintillation cocktail and the amount
of radioactive marker transported at each time interval was
determined using a TopCount NXT scintillation counter (PerkinElmer
Life Sciences, Boston, Mass.). For negative control, no polymer was
applied to the monolayers. Samples of 200 .mu.L were withdrawn from
the basolateral chamber at predetermined time intervals of 0, 5,
15, 30, 60, 90, 120, 180, 210, and 240 min and replaced with equal
volumes of fresh HBSS. After completion of the transport studies,
the polymers were removed carefully and monolayers were rinsed with
HBSS and the culture medium (DMEM) was applied on the monolayers.
The monolayers were allowed to regenerate for 2 days at 37.degree.
C. in an atmosphere of 95% air and 5% CO.sub.2 at 90% relative
humidity. TEER was monitored at 5, 6, 24, and 48 h during the
recovery period. Control transport experiments were also conducted
across Transwell.TM. filters without Caco-2 cells to determine the
filter permeability (P.sub.filter). The permeability of Caco-2 cell
monolayers (P.sub.m) was estimated by correcting the effective
permeability (P.sub.eff) for filter permeability (P.sub.filter)
according to the expression
P.sub.eff.sup.-1=P.sub.m.sup.-1+P.sub.filter.sup.-1.
[0197] Flow Cytometry
[0198] Intracellular accumulation of doxorubicin in Caco-2 cells
via P-gp-mediated efflux was studied by flow cytometry. Caco-2
cells (3.times.10.sup.5/cm.sup.2) were seeded into 24-well plates
and incubated for 3 weeks as described above. Cells were rinsed
twice with phosphate-buffered saline (PBS) and pre-incubated for 30
min at 37.degree. C. in 100 .mu.g/mL PBS suspension of microgels,
Carbopol 934NF, or Pluronic L61 or L92 (pH 7.4). At the end of the
30-min incubation period, doxorubicin was added to the culture
medium to result in its concentration of 1 .mu.g/mL. Following 3-h
incubation at 37.degree. C., the cells were washed twice with
ice-cold PBS. Then the cells were rinsed with 1 mM EDTA and 0.25%
trypsin solution, collected into centrifuge tubes and centrifuged
at 1000.times.g for 15 min, and finally resuspended in cold PBS. An
aliquot of cells was kept on ice for analysis of dye or drug
uptake.
[0199] Samples were analyzed on a FACScan flow cytometer (Becton
Dickinson Immunocytometry Systems, San Jose, Calif.) equipped with
a Spectra Physics 15-mW argon laser (.lamda..sub.ex=488 nm) and a
red 585/42 band pass filter/FL2 fluorescence detector. All flow
cytometric data were acquired and analyzed with the CellQuest
software (Becton Dickinson). Scattering signals were measured,
collected, and corrected for, in the linear scale mode. The
logarithmically amplified fluorescence emission intensity was
converted to a linear scale and expressed in arbitrary units
relative to the control sample fluorescence intensity. The negative
control was performed in drug-free medium to measure the cell
auto-fluorescence. The control experiment was performed as
described above, but with microgel-free PBS in the pre-incubation
stage. At least 10.sup.4 cells were analyzed in each sample. Each
experiment was repeated six times.
[0200] Colorimetric Cytotoxicity Assay
[0201] 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide
(MTT) assay comprises cleavage of the tetrazolium salt to a dark
blue product (formazan) by mitochondrial dehydrogenases in living
but not in dead cells [43]. Caco-2 cells used for MTT assay were
seeded onto 96 well culture plates at seeding density of
5.times.10.sup.4 cells per well in DMEM culture medium. The cells
were cultured in an atmosphere of 95% air and 5% CO.sub.2 at
37.degree. C. and 90% humidity for 48 h. The culture medium was
subsequently replaced with HBSS and microgel suspension was added
to the wells to result in a 0.5 mg/mL effective polymer
concentration in each well. As negative control no polymer was
added to the wells, and as an internal reference, 0.5 mg/mL
Carbopol in HBSS was applied to the cells. After adding the
polymers, Caco-2 cells were further incubated at 37.degree. C. for
4 h. The polymers were then removed, a 5 mg/ml MTT solution in PBS
was added to each well and the cells were incubated for another 4 h
at 37.degree. C. The reaction product was then solubilized in
dimethylsulfoxide before quantifying the color of the reaction
product using an Emax precision microplate reader (Molecular
Devices Co., Sunnyvale, Calif.) at 590 nm. In each MTT assay every
microgel was tested in five replicates in microplate wells.
[0202] Statistical Analysis
[0203] All experiments were conducted at least in triplicate. The
data were analyzed by Student's t-test at .alpha.=0.05. A
one-tailed t-test (Microsoft Excel.RTM.) (P<0.01) was used to
identify significant differences between permeability results with
additives and in the control experiments.
[0204] Example Results
[0205] The apparent permeabilities of the Caco-2 cell layers to
doxorubicin obtained in the transport experiments are collected in
Table 4 infra. As is seen, doxorubicin exhibited highly polarized
transport, with the active efflux exceeding the passive influx
4.6-fold in the case when no additives were used. However,
microgels and Pluronics (especially Pluronic L92), as well as their
combinations lowered the active efflux of doxorubicin from Caco-2
cells as much as 2.4-3.2-fold. Pluronic L61 is known to be a potent
doxorubicin efflux suppressor at concentrations up to CMC [37, 40].
At concentrations above CMC, the effects of Pluronics generally
plateau and then decay [34, 37, 40]. Surface tension of 1100
.mu.g/mL suspensions of L92-PAA-EGDMA and F127-PAA-EGDMA microgels
(XL=0.1 mol %) at 37.degree. C. (deionized water, pH adjusted to
7.4) was measured to be 38.5 and 40.4 mN/m, respectively. That is,
due to the numerous Pluronic chains exposed to the aqueous
environment, the microgels exhibit surface activity comparable to
the one of the hydrophobic Pluronic L61 or L92. Therefore, it can
be hypothesized, with some certainty, that Pluronic-PAA copolymers,
which are surface-active and solubilize lipids [14, 17, 44], can
affect the membrane proteins in a fashion analogous to Pluronics.
Verapamil, a known non-selective inhibitor of the P-gp, showed most
dramatic effect on P.sub.a.sup.b.fwdarw.a values (Table 4).
Notably, this effect was not significantly neutralized by the
presence of anionic microgels, indicating that the apparent ion
exchange kinetics of the organic base (Verapamil) between microgels
and the donor solutions were sufficiently rapid.
[0206] The passive influx of doxorubicin into Caco-2 cells was
enhanced by all studied additives, with the microgels exhibiting
the most pronounced effects (up to 2.5-fold increase in
P.sub.a.sup.a.fwdarw.b, Table 4). It has been shown that absorption
enhancers such as surfactants can act by improving drug absorption
via paracellular (primarily hydrophilic drugs) as well as
transcellular (mostly lipophilic drugs) routes [45]. Combination of
enhanced transcellular passive influx and suppressed P-gp-mediated
active influx leads to a significant accumulation of doxorubicin in
Caco-2 cells and in MDR cancer cells when Pluronics are applied at
concentrations below their CMC [38, 39]. No significant enhancement
of the paracellular drug absorption by the "unimeric" Pluronics
(i.e. in the absence of their micelles) have been reported [40,
46]. On the other hand, surfactants are generally known to enhance
paracellular transport by opening the tight junctions through an
increase in the membrane pore radius, widening of the intercellular
space, contraction of calmodulin-dependent actin microfilaments, or
contraction of the perijunctional actomyosin ring [47-49]. In
addition, the high capacity of poly(acrylic acid) to bind Ca.sup.2+
can deplete this ion from the extracellular cell medium and thus
increase the paracellular permeability of the epithelial cell
layers [50, 51]. Indications exist that Pluronic-PAA can also bind
Ca.sup.2+ in biological milieu [52]. Therefore, it was important to
address the question to what extent the dramatic increase in the
net absorption by the Pluronic-PAA microgels (alone and in
combination with Verapamil, Table 4) is due to the enhancement of
the paracellular permeability and whether the microgels are toxic
to the cells. The flow cytometry study that was carried out to
estimate the effects of the microgels on the intracellular
accumulation of doxorubicin after 3-h incubation, showed
significant enhancement of the doxorubicin uptake. That is, the
enhancement factor was measured to be 2.03.+-.0.09 and 1.78.+-.0.08
for the L92-PAA-EGDMA and F127-PAA-EGDMA microgels, respectively.
In comparison, the enhancement factors for Carbopol, Pluronic L61,
and L92 were measured to be 1.15.+-.0.04, 1.52.+-.0.08, and
1.92.+-.0.09, respectively. Herein, we define the enhancement
factor as the ratio of the integrated fluorescence intensity in the
experiment with microgel to the intensity in the control
experiment, both corrected for natural cell fluorescence. Thus the
flow cytometry results demonstrated significant enhancement of the
intracellular uptake by both microgels and Pluronics alone and
hinted at the prevalence of the paracellular route. TABLE-US-00008
TABLE 4 Effect of microgels, Pluronic L61, Pluronic L92, and
Verapamil on doxorubicin transport.sup.a and absorption by Caco-2
cells. Treatment (Expt. No. in Table 1) P a b .fwdarw. a 10 6 ,
##EQU7## cm/s P a a .fwdarw. b 10 6 , ##EQU8## cm/s Net absorption
(secretion).sup.b, % Control (1) 2.81 .+-. 0.03 0.61 .+-. 0.04
(360) Pluronic L61 (2) 0.89 .+-. 0.04 1.12 .+-. 0.03 -21 Pluronic
L92 (3) 0.68 .+-. 0.04 1.17 .+-. 0.03 -42 L92-PAA-EGDMA (4) 1.12
.+-. 0.03 1.55 .+-. 0.03 -28 L92-PAA-EGDMA + Pluronic L61 (5) 0.95
.+-. 0.04 1.46 .+-. 0.03 -35 L92-PAA-EGDMA + Pluronic L92 (6) 0.59
.+-. 0.04 1.26 .+-. 0.04 -53 F127-PAA-EGDMA (7) 1.12 .+-. 0.04 1.32
.+-. 0.04 -15 F127-PAA-EGDMA + Pluronic L61 (8) 1.16 .+-. 0.03 1.44
.+-. 0.04 -19 F127-PAA-EGDMA + Pluronic L92 (9) 0.57 .+-. 0.03 1.23
.+-. 0.04 -54 Verapamil (10) 0.45 .+-. 0.05 0.88 .+-. 0.04 -49
L92-PAA-EGDMA + verapamil (11) 0.49 .+-. 0.05 1.39 .+-. 0.05 -65
F127-PAA-EGDMA + verapamil (12) 0.54 .+-. 0.05 1.29 .+-. 0.05 -58
.sup.aApparent permeabilities with P .ltoreq. 0.05 b .times.
Calculated .times. .times. using .times. .times. the .times.
.times. formula : .times. Net .times. .times. effect = 100 P a b
.fwdarw. a - P a a .fwdarw. b P a a .fwdarw. b ##EQU9##
[0207] Integrity of Caco-2 cell monolayers and opening of tight
junctions can be assessed by measuring the flux of small
hydrophilic radiolabeled molecules such as .sup.14C-mannitol across
the monolayers, as well as by TEER [53]. Transport of
.sup.14C-mannitol across Caco-2 monolayers was assessed in the
presence of microgels as well as benign polymer widely used in oral
applications (Carbopol 934NF), using HBSS as a negative control. As
measured by radioactivity count, total cumulative transport of
.sup.14C-mannitol was relatively minor in all instances and did not
exceed 3.5% of initial concentration in the donor compartment (FIG.
15).
[0208] Using the relative release kinetics, the effective
permeability (P.sub.eff) of monolayers was calculated as described
in Experimental section (Table 5). As is seen, at concentrations of
0.1 mg/mL (as in Table 4) either Carbopol or microgels did not
significantly enhance the P.sub.eff. At concentrations of 0.5
mg/mL, the microgels and Carbopol significantly increased the
P.sub.eff as compared to the negative control, but the differences
between the microgels and Carbopol were insignificant. This is an
important result indicating that although our microgels do result
in the enhancement of the intracellular doxorubicin transport
(Table 4), they do not provoke any dramatic changes in the
paracellular permeability. The microgels compared favorably with
Carbopol (lightly cross-linked poly(acrylic acid)), which is an
industry standard in formulations that require adhesion to
gastrointestinal tissues [54, 55]. TABLE-US-00009 TABLE 5 Effective
permeability (P.sub.eff) of Caco-2 cell monolayers (mean .+-. S.D.
of 3-4 experiments) for .sup.14C-mannitol. Polymer concentration,
P.sub.eff .times.10.sup.7, Permeability Sample/Additive mg/mL cm/s
ratio .sup.a Control 0 2.74 .+-. 0.44 1.0 Carbopol 0.1 3.36 .+-.
0.75 1.2 0.5 5.05 .+-. 1.45 1.8 L92-PAA-EGDMA 0.1 3.39 .+-. 0.92
1.2 0.5 3.89 .+-. 0.83 1.4 F127-PAA-EGDMA 0.1 4.43 .+-. 1.39 1.6
0.5 7.58 .+-. 1.26 2.8 .sup.a Relative to the Control experiment (P
.ltoreq. 0.05).
[0209] The observed tendency of added polymers (at 0.5 mg/mL level)
to increase permeability of Caco-2 layers might be an indication
that the polymers affect the integrity of cell membrane. Therefore,
the reversibility of this effect is an important issue when
screening these polymers as penetration enhancers. Herein, it was
observed that after removing the polymers from the monolayers, TEER
values completely recovered to initial values within 2 days,
indicating that the effects, if any, of microgels on tight
junctions are fully reversible (FIG. 16). It should be noted that
at 0.1 mg/mL level, where microgels exhibited significant effects
on the net absorption of doxorubicin (Table 4), the TEER was not
significantly affected, which is an evidence that the transport
across the Caco-2 monolayers in the presence of microgels is
dominated by the transcellular, and not paracellular, pathway.
[0210] The MTT assay showed no toxic effects caused by mucosal
application of the microgels in comparison with the negative
control: 99.+-.12, 97.+-.11 and 97.+-.15% of the cells were viable
after application of microgels L92-PAA-EGDMA, F127-PAA-EGDMA, and
Carbopol, respectively. Using the MTT assay, the polymer-treated
cells were able to metabolize the mitochondrial substrate MTT by
conversion into formazan crystals. This metabolic activity of cells
is an appropriate technique for assessing the number of viable
cells, since damaged or dead cells are devoid of any mitochondrial
dehydrogenase activity [56]. Thus the Caco-2 cell monolayers
appeared to be viable after 4 h application of microgels and no
damage was observed at the intracellular level. Overall, the effect
of microgels on mitochondrial dehydrogenase activity revealed their
benign nature.
[0211] By inhibiting the P-gp-mediated doxorubicin efflux from the
cells and enhancing the passive influx, the lightly cross-linked
Pluronic-PAA microgels enhance the overall absorption of the drug
by the cells. Notably, this effect is more pronounced that with a
known penetration enhancer, Pluronic L61, and is comparable to the
other relatively hydrophobic copolymer, Pluronic L92. Microgels
exhibit synergism with Verapamil, a non-selective inhibitor of the
P-gp. Judging by .sup.14C-mannitol permeability, the microgels do
not damage cells, so that no meaningful enhancement of the
paracellular transport is observed. Any effect of microgels on
trans-epithelial electrical resistance appears to be fully
reversible. Notably, materials comprising slightly cross-linked
poly(acrylic acid) have demonstrated no systemic absorption in
gastrointestinal transit experiments both in vitro and in vivo [57,
58].
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[0271] All publications and patents mentioned in this specification
are herein incorporated by reference. Various modifications and
variations of the described composition of matter, methods of
manufacture and methods of use of the invention will be apparent to
those skilled in the art without departing from the scope and
spirit of the invention. Although the invention has been described
in connection with specific preferred embodiments, it should be
understood that the invention as claimed should not be unduly
limited to such specific embodiments. Indeed, various modifications
of the described modes for carrying out the invention which are
obvious to those skilled in polymer chemistry and formulation are
intended to be within the scope of the following claims.
* * * * *