U.S. patent application number 11/344689 was filed with the patent office on 2006-08-10 for polymer particle delivery compositions and methods of use.
This patent application is currently assigned to MediVas, LLC. Invention is credited to Zaza D. Gomurashvili, Ramaz Katsarava, Hong Li, William G. Turnell.
Application Number | 20060177416 11/344689 |
Document ID | / |
Family ID | 56290776 |
Filed Date | 2006-08-10 |
United States Patent
Application |
20060177416 |
Kind Code |
A1 |
Turnell; William G. ; et
al. |
August 10, 2006 |
Polymer particle delivery compositions and methods of use
Abstract
The present invention provides biodegradable polymer particle
delivery compositions based on polymers, such as polyester amide
(PEA) and polyester urethane (PEUR) polymers, that contain amino
acids in the polymer. The polymer particle delivery compositions
can be formulated as a liquid dispersion of polymer particles with
the bioactive agents dispersed in the particle or conjugated
attached to polymer molecules or particle surfaces. The bioactive
agents can include drugs, polypeptides, DNA and cells for
cell-based therapies using particles sized for local, mucosal or
circulatory delivery. Methods of treating a disease by
administering to a subject the polymer particle delivery
composition, which incorporates a bioactive agent suitable for
treatment of the disease, or its symptoms, are also included.
Inventors: |
Turnell; William G.; (San
Diego, CA) ; Li; Hong; (San Diego, CA) ;
Gomurashvili; Zaza D.; (San Diego, CA) ; Katsarava;
Ramaz; (Tbilisi, GA) |
Correspondence
Address: |
DLA PIPER RUDNICK GRAY CARY US, LLP
4365 EXECUTIVE DRIVE
SUITE 1100
SAN DIEGO
CA
92121-2133
US
|
Assignee: |
MediVas, LLC
San Diego
CA
|
Family ID: |
56290776 |
Appl. No.: |
11/344689 |
Filed: |
January 31, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10362848 |
Oct 14, 2003 |
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11344689 |
Jan 31, 2006 |
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60654715 |
Feb 17, 2005 |
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60684670 |
May 25, 2005 |
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60737401 |
Nov 14, 2005 |
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60687570 |
Jun 3, 2005 |
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60759179 |
Jan 13, 2006 |
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60719950 |
Sep 22, 2005 |
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Current U.S.
Class: |
424/78.27 ;
514/44R |
Current CPC
Class: |
A61P 19/06 20180101;
Y10S 977/788 20130101; A61K 9/1647 20130101; A61K 47/593 20170801;
A61K 47/595 20170801; A61K 9/1075 20130101; A61P 1/00 20180101;
Y10S 977/773 20130101; A61K 47/34 20130101; A61K 47/59 20170801;
C07K 16/2821 20130101; C08L 77/12 20130101; A61P 31/00 20180101;
Y10S 977/906 20130101; C12N 15/88 20130101; A61K 9/5031 20130101;
A61P 29/00 20180101; A61K 9/5153 20130101; A61P 27/16 20180101;
A61P 27/02 20180101 |
Class at
Publication: |
424/078.27 ;
514/044 |
International
Class: |
A61K 48/00 20060101
A61K048/00; A61K 31/785 20060101 A61K031/785 |
Claims
1. A polymer particle delivery composition in which a
therapeutically effective amount of at least one bioactive agent is
dispersed in a biodegradable polymer, wherein the polymer is a PEA
having a chemical formula described by structural formula (I),
##STR40## wherein n ranges from about 5 to about 150; R.sup.1is
independently selected from residues of
.alpha.,.omega.-bis(4-carboxyphenoxy)-(C.sub.1-C.sub.8) alkane,
3,3'-(alkanedioyldioxy)dicinnamic acid or
4,4'-(alkanedioyldioxy)dicinnamic acid, (C.sub.2 - C.sub.20)
alkylene, (C.sub.2-C.sub.20) alkenylene or a saturated or
unsaturated residues of therapeutic di-acids; the R.sup.3s within
an individual n monomer are independently selected from the group
consisting of hydrogen, (C.sub.1-C.sub.6) alkyl, (C.sub.2-C.sub.6)
alkenyl, (C.sub.2-C.sub.6) alkynyl, (C.sub.6-C.sub.10) aryl
(C.sub.1-C.sub.6) alkyl, -(CH.sub.2)C.sub.3, and
-CH.sub.2)C.sub.2S(CH.sub.2); and R.sup.4 is independently selected
from the group consisting of (C.sub.2-C.sub.20) alkylene,
(C.sub.2-C.sub.20) alkenylene, (C.sub.2-C.sub.8) alkyloxy,
(C.sub.2-C.sub.20) alkylene, bicyclic-fragments of
1,4:3,6-dianhydrohexitols of general structural formula(II), and
combinations thereof, (C.sub.2-C.sub.20) alkylene,
(C.sub.2-C.sub.20) alkenylene and saturated or unsaturated
therapeutic di-acid residues; ##STR41## ##STR42## wherein n ranges
from about 5 to about 150, m ranges about 0.1 to 0.9: p ranges from
about 0.9 to 0. 1; wherein R.sup.1is independently selected from
residues of
.alpha.,.omega.)-bis(4-carboxyphenoxy)-(C.sub.1-C.sub.8) alkane,
3,3'-(alkanedioyldioxy)dicinnamic acid or 4,4'-(alkanedioyldioxy)
dicinnamic acid, (C.sub.2-C.sub.20) alkylene, (C.sub.2-C.sub.20)
alkenylene or a saturated or unsaturated residues of therapeutic
di-acids; each R.sup.2 is independently hydrogen,
(C.sub.1-C.sub.12) alkyl or (C.sub.6-C.sub.10) aryl or a protecting
group; the R.sup.3S within an individual m monomer are
independently selected from the group consisting of hydrogen,
(C.sub.1-C.sub.6) alkyl, (C.sub.2-C.sub.6) alkenyl,
(C.sub.2-C.sub.6) alkynyl, (C.sub.6-C.sub.10) aryl
(C.sub.1-C.sub.6) alkyl, -CH.sub.2)C.sub.3, and
-CH.sub.2).sub.2S(CH.sub.2); and R.sup.4 is independently selected
from the group consisting of (C.sub.2-C.sub.20) alkylene,
(C.sub.2-C.sub.20) alkenylene, (C.sub.2-C.sub.8) alkyloxy,
(C.sub.2-C.sub.20) alkylene, bicyclic-fragments of
1,4:3,6-dianhydrohexitols of structural formula(II), and
combinations thereof, and residues of saturated or unsaturated
therapeutic diols; or a PEUR polymer having a chemical formula
described by structural formula (IV), ##STR43## and wherein n
ranges from about 5 to about 150; wherein the R .sup.3s within an
individual n monomer are independently selected from the group
consisting of hydrogen, (C.sub.1-C.sub.6) alkyl, (C.sub.2-C.sub.6)
alkenyl, (C.sub.2-C.sub.6) alkynyl, (C.sub.6-C.sub.10)
aryl(C.sub.1-C.sub.6) alkyl, -(CH.sub.2).sub.3, and
-(CH.sub.2).sub.2S(CH.sub.2); R.sup.4 is selected from the group
consisting of (C.sub.2-C.sub.20) alkylene, (C.sub.2-C.sub.20)
alkenylene or alkyloxy, and bicyclic-fragments of
1,4:3,6-dianhydrohexitols of structural formula (II); and R.sup.6
is independently selected from (C.sub.2-C.sub.20) alkylene,
(C.sub.2-C.sub.20) alkenylene or alkyloxy, bicyclic-fragments of
1,4:3,6-dianhydrohexitols of general formula (II), a residue of a
saturated or unsaturated therapeutic diol, and mixtures thereof. or
a PEUR polymer having a chemical structure described by general
structural formula (V) ##STR44## wherein n ranges from about 5 to
about 150, m ranges about 0.1 to about 0.9: p ranges from about 0.9
to about 0.1; R.sup.2 is independently selected from hydrogen,
(C.sub.6-C.sub.10) aryl (C.sub.1-C.sub.6) alkyl, or a protecting
group; the R.sup.3s within an individual m monomer are
independently selected from the group consisting of hydrogen,
(C.sub.1-C.sub.6) alkyl, (C.sub.2-C.sub.6) alkenyl,
(C.sub.2-C.sub.6) alkynyl, (C.sub.6-C.sub.10) aryl(C.sub.1-C.sub.6)
alkyl, -CH.sub.2).sub.3- as pyrrolidine-2-carboxylic acid and
-CH.sub.2).sub.2S(CH.sub.2); R.sup.4 is selected from the group
consisting of (C.sub.2-C.sub.20) alkylene, (C.sub.2-C.sub.20)
alkenylene or alkyloxy, and bicyclic-fragments of
1,4:3,6-dianhydrohexitols of structural formula (II); and R.sup.6
is independently selected from (C.sub.2-C.sub.20) alkylene,
(C.sub.2-C.sub.20) alkenylene or alkyloxy, bicyclic-fragments of
1,4:3,6-dianhydrohexitols of general formula (II), a residue of a
saturated or unsaturated therapeutic diol, and mixtures thereof. or
a biodegradable PEU polymer having a chemical formula described by
general structural formula (VI): ##STR45## wherein n is about 10 to
about 150; the R.sup.3s within an individual n monomer are
independently selected from hydrogen, (C.sub.1-C.sub.6) alkyl,
(C.sub.2-C.sub.6) alkenyl, (C.sub.2-C.sub.6) alkynyl,
(C.sub.6-C.sub.10) aryl (C.sub.1-C.sub.6) alkyl, -CH.sub.2).sub.3,
and -CH.sub.2).sub.2S(CH.sub.2); R.sup.4 is independently selected
from (C.sub.2-C.sub.20) alkylene, (C.sub.2-C.sub.20) alkenylene,
(C.sub.2-C.sub.8) alkyloxy (C.sub.2-C.sub.20) alkylene, a residue
of a saturated or unsaturated therapeutic diol; or a
bicyclic-fragment of a 1,4:3,6-dianhydrohexitol of structural
formula (II), and mixtures thereof; or PEU having a chemical
formula described by structural formula (VII) ##STR46## wherein m
is about 0.1 to about 1.0; p is about 0.9 to about 0.1; n is about
10 to about 150; each R.sup.2 is independently hydrogen,
(C.sub.1-C.sub.12) alkyl or (C.sub.6-C.sub.10) aryl; the R.sup.3s
within an individual m monomer are independently selected from
hydrogen, (C.sub.1-C.sub.6) alkyl, (C.sub.2-C.sub.6) alkenyl,
(C.sub.2-C.sub.6) alkynyl, (C.sub.6 -C.sub.10) aryl
(C.sub.1-C.sub.6)alkyl, -(CH.sub.2).sub.3, and
-CH.sub.2).sub.2S(CH.sub.2); each R.sup.4 is independently selected
from (C.sub.2-C.sub.20) alkylene, (C.sub.2-C.sub.20) alkenylene,
(C.sub.2-C.sub.8) alkyloxy (C.sub.2-C.sub.20) alkylene, a residue
of a saturated or unsaturated therapeutic diol; or a
bicyclic-fragment of a 1,4:3,6-dianhydrohexitol of structural
formula (II), and mixtures thereof.
2. The composition of claim 1, wherein the composition is
formulated for administration in the form of a liquid dispersion of
the polymer particles.
3. The composition of claim 1, wherein the composition is
lyophilized.
4. The composition of claim 1, wherein the polymer comprises at
least one hydrophilic side functional group.
5. The composition of claim 4, wherein the side functional group is
-COOH.
6. The composition of claim 1, wherein the polymer has the chemical
formula described by structural formula (I), (IV) or (VII) and
R.sub.3s in at least one monomer n is CH.sub.2Ph.
7. The composition of claim 1, wherein ##STR47##
8. The composition of claim 7, wherein R.sub.1is selected from
-CH.sub.2-CH=CH-CH.sub.2-,-(CH.sub.2).sub.4-,-(CH.sub.2).sub.6-,
and -(CH.sub.2).sub.8-.
9. The composition of claim I, wherein the 1
,4:3,6-dianhydrohexitol of structural formula (II) is derived from
D-glucitol, D-mannitol, or L-iditol.
10. The composition of claim 1, wherein the composition forms a
time release polymer depot when administered in vivo.
11. The composition of claim 1, wherein the composition biodegrades
over a period of twenty-four hours, about seven days, about thirty
days, or about 90 days.
12. The composition of claim 1, wherein the composition is in the
form of particles having an average diameter in the range from
about 10 nanometers to about 1000 microns.
13. The composition of claim 1, wherein the at least one bioactive
agent is conjugated to the polymer on the exterior of the
particles.
14. The composition of claim 13, wherein the bioactive agent is
selected from the group consisting of a targeting ligand, a drug,
an antigen and an antibody.
15. The composition of claim 1, further comprising a covering water
soluble molecule conjugated to the polymer on the exterior of the
particles.
16. The composition of claim 15, wherein the covering water soluble
molecule is selected from the group consisting of poly(ethylene
glycol) (PEG); phosphoryl choline (PC); glycosaminoglycans;
polysaccharides; poly(ionizable or polar amino acids); chitosan and
alginate.
17. The composition of claim 16, wherein the glycosaminoglycan is
heparin and the polysaccharide is polysialic acid.
18. The composition of claim 1, wherein a particle includes from
about 5 to about 150 molecules of bioactive agent per polymer
molecule chain.
19. The composition of claim 1, wherein a polymer molecule in the
particles has an average molecular weight in range from about 5,000
to about 300,000.
20. The composition of claim 1, wherein the at least one bioactive
agent is conjugated to a polymer molecule in the particles.
21. The composition of claim 1, wherein a polymer molecule has from
about 5 to about 70 molecules of bioactive agents attached
thereto.
22. The composition of claim 1, wherein the polymer is contained in
a polymer-bioactive agent conjugate having structural formula VIII:
##STR48## wherein n, m, p, R.sup.1, R.sup.3, and R.sup.4 are as
above, R.sup.5 is selected from the group consisting of --O-, -S-,
and -NR.sup.8-, wherein R.sup.8 is H or (C.sub.1-C.sub.8)alkyl; and
R.sup.7 is the bioactive agent.
23. The composition of claim 22, except that two or more molecules
of the polymer are crosslinked to provide an -R.sup.5-R.sup.7-
R.sup.5 conjugate.
24. The composition of claim 22, except that the bioactive agent is
covalently linked to two parts of a single polymer molecule of
structural formula IV through the
-R.sup.5-R.sup.7-R.sup.5-conjugate and R.sup.5 is independently
selected from the group consisting of--O-, -S-, and -NR.sup.8-,
wherein R.sup.8 is H or (C.sub.1-C.sub.8) alkyl; and R.sup.7 is the
bioactive agent.
25. The composition of claim 23, except that R.sup.1 is
independently (C.sub.2-C.sub.20) alkylene or (C.sub.2-C.sub.20)
alkenylene, and wherein one of R.sup.5 is --X-Y-, wherein X is
selected from the group consisting of (C.sub.1-C.sub.18) alkylene,
substituted alkylene, (C.sub.3-C.sub.8) cycloalkylene, substituted
cycloalkylene, 5-6 membered heterocyclic system containing 1-3
heteroatoms selected from the group consisting of O, N, and S,
substituted heterocyclic, (C.sub.2-C.sub.18) alkenyl, substituted
alkenyl, alkynyl, substituted alkynyl, C.sub.6 and C.sub.10 aryl,
substituted aryl, heteroaryl, substituted heteroaryl, alkylaryl,
substituted alkylaryl, arylalkynyl, substituted arylalkynyl,
arylalkenyl, substituted arylalkenyl, arylalkynyl, substituted
arylkynyl and wherein the substituents are selected from the group
consisting of H, F, Cl, Br, I, (C.sub.1-C.sub.6) alkyl, -CN,
-NO.sub.2, -OH, -O(C.sub.1-C.sub.4) alkyl, -S(C.sub.1-C.sub.6)
alkyl, -S[(=O)(C.sub.1-C.sub.6) alkyl],
-S[(O.sub.2)(C.sub.1`-C.sub.6) alkyl],-C[(=O)(C.sub.1-C.sub.6)
alkyl], CF.sub.3,-O[(CO)-(C.sub.1-C.sub.6) alkyl],
-S(OC.sub.2)[N(R.sup.9R.sup.10 )], -NH[(C=O)(C.sub.1-C.sub.6)
alkyl],-NH(C=O)N(R.sup.9R.sup.10), and -N(R.sup.9R.sup.10); wherein
R.sup.9 and R.sup.10 are independently H or (C.sub.1-C.sub.6)
alkyl; and Y is selected from the group consisting of --O-, -S-,
-S-S-, -S(O)-,-S(O.sub.2)-, -NR.sup.8-,
-C(=O)-,-OC(=O)-,-C(=O)O-,-OC(=O)NH-,-NR.sup.8C(=O)-,-C(=O)NR.sup.8-,-NR.-
sup.8C(=O)NR.sup.8-, -NR.sup.8C(=O)NR.sup.8-,
and-NR.sup.8C(=S)NR.sup.8-.
26. The composition of claim 25, except that each R.sup.5 is
-X-Y-.
27. The composition of claim 22, comprising four molecules of the
polymer, except that only two of the repeating units omit R.sup.7
and are crosslinked to provide a single
-R.sup.5-X-R.sup.5-conjugate, wherein X is selected from the group
consisting of (C.sub.1-C.sub.18) alkylene, substituted alkylene,
(C.sub.3-C.sub.8) cycloalkylene, substituted cycloalkylene, 5-6
membered heterocyclic system containing 1-3 heteroatoms selected
from the group consisting of O, N, and S, substituted heterocyclic,
(C.sub.2-C.sub.18) alkenyl, substituted alkenyl, alkynyl,
substituted alkynyl, C.sub.6 and C.sub.10aryl, substituted aryl,
heteroaryl, substituted heteroaryl, alkylaryl, substituted
alkylaryl, arylalkynyl, substituted arylalkynyl, arylalkenyl,
substituted arylalkenyl, arylalkynyl, substituted arylkynyl and
wherein the substituents are selected from the group consisting of
H, F, Cl, Br, I, (C.sub.1-C.sub.6) alkyl, -CN, -NO.sub.2, -OH,
-O(C.sub.1-C.sub.4) alkyl, -S(C.sub.1-C.sub.6) alkyl,
-S[(=O)(C.sub.1-C.sub.6) alkyl], -S[(O.sub.2)(C.sub.1-C.sub.6)
alkyl], -C[(=O)(C.sub.1-C.sub.6) alkyl],
CF.sub.3,-O[(CO)-(C.sub.1-C.sub.6) alkyl)],
-S(O.sub.2)[N(R.sub.9R.sub.10)], -NH[(C=O)(C.sub.1-C.sub.6) alkyl],
-NH(C=O)N(R.sup.9R.sup.10), and -N(R.sup.9R.sup.10); wherein
R.sup.9 and R.sup.10 are independently H or (C.sub.1-C.sub.6)
alkyl.
28. The composition of claim 22, except that two molecules of the
polymer are partially crosslinked to provide an
-R.sup.5-X-Y-R.sup.7-R.sup.5-conjugate.
29. The composition of claim 24, except that one molecule of the
polymer is covalently linked to the bioactive agent through an
-R.sup.5-R.sup.7-Y-X- R.sup.5-bridge, (Formula XI). ##STR49##
wherein, X is selected from the group consisting of
(C.sub.1-C.sub.18) alkylene, substituted alkylene,
(C.sub.3-C.sub.8) cycloalkylene, substituted cycloalkylene, 5-6
membered heterocyclic system containing 1-3 heteroatoms selected
from the group consisting of O, N, and S, substituted heterocyclic,
(C.sub.2-C.sub.18) alkenyl 1, substituted alkenyl, alkynyl,
substituted alkynyl, C.sub.6 and C.sub.10) aryl, substituted aryl,
heteroaryl, substituted heteroaryl, alkylaryl, substituted
alkylaryl, arylalkynyl, substituted arylalkynyl, arylalkenyl,
substituted arylalkenyl, arylalkynyl, substituted arylkynyl,
wherein the substituents are selected from the group consisting of
H, F, Cl, Br, I, (C.sub.1-C.sub.6) alkyl, -CN, -NO.sub.2, -OH,
-O(C.sub.1-C.sub.4) alkyl, -S(C.sub.1-C.sub.6) alkyl,
-S[(=O)(C.sub.1-C.sub.6) alkyl], -S[(O.sub.2)(C.sub.1-C.sub.6)
alkyl], -C[(=O)(C.sub.1-C.sub.6) alkyl], CF.sub.3,-O[(CO)-(C.sub.1
-C.sub.6)alkyl], -S(O.sub.2)[N(R.sup.9R.sup.10)],
-NH[(C=O)(C.sub.1-C.sub.6)alkyl], -NH(C=O)N(R.sup.9R.sup.10), and
-N(R.sup.11R.sup.12), wherein R.sup.1 is independently (C.sub.2
-C.sub.20) alkylene or (C.sub.2-C.sub.20) alkenylene, and R.sup.11
and R.sup.12 are independently H or (C.sub.1-C.sub.6) alkyl.
30. The composition of claim 28, except that one molecule of the
polymer is covalently linked to the bioactive agent through the
conjugate and R.sup.1 is (C.sub.2- C.sub.20) alkylene or
(C.sub.2-C.sub.20) alkenylene.
31. The composition of claim 1, wherein the composition forms a
time release polymer depot when administered in vivo.
32. The composition of claim 1, wherein the composition the
particles have an average diameter in the range from about 10
nanometers to about 1000 microns and the at least one bioactive
agent is dispersed in the particles.
33. The composition of claim 32, wherein the particles further
comprise a covering of the polymer.
34. The composition of claim 1, wherein a particle has from about 5
to about 150 molecules of the bioactive agent per polymer
molecule.
35. The composition of claim 1, wherein a polymer molecule has from
about 5 to about 70 molecules of bioactive agents attached
thereto.
36. The composition of claim 1, wherein the composition further
comprises a pharmaceutically acceptable vehicle.
37. The composition of claim 1, wherein the composition is in the
form of disperse droplets containing the particles in a mist.
38. The composition of claim 37, wherein the mist is produced by a
nebulizer.
39. The composition of claim 1, wherein the composition is
contained within a nebulizer actuatable to produce a mist
comprising dispersed droplets of the vehicle.
40. The composition of claim 1, wherein the composition is
contained within an injection device that is actuatable to
administer the composition by injection.
41. The composition of claim 1, wherein the bioactive agent is
hydrophilic and is selected from the group consisting of a
hydrophilic drug, peptide, protein, lipid, sugar, RNA and DNA.
42. The composition of claim 41, wherein the DNA is a gene
contained in an expression system suitable for expression of the
gene.
43. The composition of claim 42, wherein the expression system
comprises an adenovirus vector.
44. The composition of claim 1, wherein the particles encapsulate
an aqueous solution containing at least one smaller particle of the
polymer in which the at least one bioactive agent is dispersed.
45. The composition of claim 1, wherein the particles encapsulate
an aqueous solution containing the at least one bioactive
agent.
46. The composition of claim 1, wherein the bioactive agent is
contained in a polymer/bioactive agent mixture and the particles
further comprise a covering formed by a different polymer in which
the mixture is not soluble.
47. The composition of claim 1, wherein the polymer forms a
covering for the particles and the particles further comprise a
mixture of the bioactive agent and a different polymer in which the
mixture is not soluble.
48. The composition of claim 1, wherein the bioactive agent is
hydrophobic and is selected from the group consisting of a
hydrophobic drug, peptide, protein, lipid, fat and sugar.
49. A micelle-forming polymer particle delivery composition
comprising at least one bioactive agent dispersed in a
biodegradable polymer comprising a) a hydrophobic section
comprising a biodegradable polymer having a chemical structure
described by structural formula (I), and b) a water soluble section
comprising at least one block of ionizable poly(amino acid), or the
water soluble section comprises repeating alternating units of: i)
polyethylene glycol, polyglycosaminoglycan, or polysaccharide; and
ii) at least one ionizable or polar amino acid, wherein the
repeating alternating units have substantially similar molecular
weights and wherein the molecular weight of the polymer is in the
range from about 10 kD to 300kD.
50. The composition of claim 49, wherein the molecular weight of
the polymer is over 10 kD and at least one of the amino acid units
is an ionizable or polar amino acid selected from the group
consisting of serine, glutamic acid, aspartic acid, lysine and
arginine.
51. The composition of claim 49 wherein the repeating alternating
units have substantially similar molecular weights in the range
from about 300 D to about 700 D.
52. The composition of claim 49, further comprising a
pharmaceutically acceptable aqueous media with a pH value at which
at least a portion of the ionizable amino acids in the water
soluble chain are ionized, and wherein the composition forms
micelles.
53. The composition of claim 49, wherein the micelles have an
average size in the range from about 20 nm to about 200 nm.
54. The composition of claim 49, wherein the bioactive agent is
selected from the group consisting of a small molecule drug, a
peptide, a protein, lipid, sugar, DNA, cDNA or RNA.
55. The composition of claim 49, wherein the water soluble section
of the polymer has a molecular weight in the range from about 5 kD
to about 100 kD.
56. The composition of claim 49, wherein the complete water soluble
section of the polymer comprises ionizable or polar water soluble
poly(amino acids).
57. The composition of claim 49, wherein the hydrophobic section of
the polymer has a chemical structure described by structural
formula I.
58. The composition of claim 57, wherein the polymer comprises a
moiety selected from carboxylate phenoxy propene (CPP),
leucine-1,4:3,6-dianhydro-D-sorbitol (DAS), and combinations
thereof.
59. A method for treating a disease of interest in a subject by
administering to the subject in vivo a invention polymer particle
delivery composition of claim 1 in the form of a liquid dispersion
of polymer particles that incorporate at least one bioactive agent
selected to treat the disease, which particles biodegrade by
enzymatic action to release the bioactive agent over time.
60. A method of delivering polymer particles containing one or more
bioactive agents to a local site in the body in a subject in need
thereof, said method comprising injecting a dispersion of the
polymer particles to an in vivo site in the body of the subject
where the injected particles agglomerate to form a polymer depot of
particles of increased size, wherein the particles comprise a
polymer containing at least one amino acid and a non-amino acid
moiety per repeat unit of the polymer.
61. The method of claim 60, wherein the particles have an average
diameter in the range from about 1 .mu.m to about 200 .mu.m.
62. The method of claim 60, wherein the polymer has a chemical
formula described by structural formula (I).
63. The method of claim 60, wherein the injection is administered
intramuscularly, subcutaneously, intravenously, into the Central
Nervous System (CNS), into the peritoneum or intraorgan.
64. The composition of claim 1, wherein the composition is
formulated for intrapulmonary or gastroenteral delivery.
Description
RELATED APPLICATIONS
[0001] This application claims priority under .sctn.35 U.S.C.
119(e) from provisional application Ser. Nos. 60/654,715, filed
Feb. 17, 2005; 60/684,670, filed May 25, 2005; 60/737,401, filed
Nov. 14, 2005; 60/687,570, filed Jun. 3, 2005; 60/759,179, filed
Jan. 13, 2006; and 60/719,950, filed Sep. 22, 2005, and this
application is a continuation in part application under 35 U.S.C.
.sctn.120 of U.S. Ser. No. 10/362,848, filed Oct. 14, 2003 and U.S.
Pat. No. 6,503,538 B1, each of which is incorporated herein by
reference in its entirety.
FIELD OF THE INVENTION
[0002] The invention relates, in general, to drug delivery systems
and, in particular, to polymer particle delivery compositions that
can delivery a variety of different types of molecules in a time
release fashion.
BACKGROUND INFORMATION
[0003] FDA-approved controlled-delivery polymer wafer-Gliadel.RTM.
(Guilford Pharmaceutical Corp, Baltimore, Md.), is the combination
of a copolyanhydride matrix consisting of CPP and sebacic acid (in
20 to 80 molar ratios,) in which the anticancer agent is physically
admixed (W. Dang et al. J Contr. Rel. (1996) 42:83-92). Hydrolytic
degradation products of Gliadel.RTM. wafer (in addition to the
anticancer agent) are ultimately the starting di-acids: sebacic
acid and CPP. Clinical investigations of Gliadel implants in rabbit
brains have shown limited toxicity, initial activity and fast
excretion of decomposition products - the free acids (A.J. Domb et
al. Biomaterials. (1995) 16:1069-1072).
[0004] More recently CPP was disclosed as a monomer useful in
preparation of bioabsorbable stents for vascular applications by
"Advanced Cardiovascular Systems, Inc", in patent WO 03/080147 A1,
2003 and polymer particles in co-pending provisional application
Ser. No. 60/684,670, filed May 25, 2005.
[0005] Another aromatic biodegradable di-acid monomer based on
trans-4-hydroxycinnamic acid has been recently described. The
monomer with general name 4,4'-(alkanedioyldioxy) dicinnamic acid
inherently contains two hydrolytically labile ester groups, and is
expected to undergo specific (enzymatic) and nonspecific (chemical)
hydrolysis (M Nagata, Y. Sato. Polymer. (2004) 45:87-93). The
biodegradable polymers containing unsaturated groups have potential
for various applications. For example, unsaturated groups can be
converted into other functional groups such as epoxy or
alcohol-useful for further modifications. Their crosslinking could
enhance thermal and mechanical properties of polymer. Cinnamate is
known to undergo reversible [2+2] cycloaddition on UV irradiation
at wavelengths over 290 nm, without presence of photoinitiator,
which makes the polymer self-photo-crosslinkable (Y. Nakayama, T.
Matsuda. J Polym. Sci. Part A: Polym. Chem. (1992) 30:2451-2457).
In addition, the cinnamoyl group is metabolized in the body and has
been proven to be non-toxic (Citations in paper of M Nagata, Y.
Sato. Polymer. (2004) 45:87-93).
[0006] Recent research has also shown that hydrogel-type materials
can be used to shepherd various medications through the stomach and
into the more alkaline intestine. Hydrogels are cross-linked,
hydrophilic, three-dimensional polymer networks that are highly
permeable to various drug compounds, can withstand acidic
environments, and can be tailored to "swell" and thereby release
entrapped molecules through their weblike surfaces. Depending on
the chemical composition of the gel, different internal and
external stimuli (e.g., changes in pH, application of a magnetic or
electric field, variations in temperature, and ultrasound
irradiation) may be used to trigger the swelling effect. Once
triggered, however, the rate of entrapped drug release is
determined solely by the cross-linking ratio of the polymer
network.
[0007] Chemists, biochemists, and chemical engineers are all
looking beyond traditional polymer networks to find innovative drug
transport systems. Thus, there is still a need in the art for new
and better polymer particle delivery compositions for controlled
delivery of a variety of different types of bioactive agents.
SUMMARY OF THE INVENTION;
[0008] The present invention is based on the premise that polymers
containing at least one amino acid and a non-amino acid moiety per
repeat unit, such as polyester amide (PEA) polyester urethane
(PEUR) and polyester urea (PEU) polymers, can be used to formulate
biodegradable polymer particle delivery compositions for time
release of bioactive agents in a consistent and reliable manner.
The present invention is also based on the premise that PEAs, PEURs
and PEUs can be formulated as polymer delivery compositions that
incorporate a therapeutic agent (i.e, a residue of a therapeutic
diol or di-acid) into the backbone of the polymer for time release
of the therapeutic agent from the backbone of the polymer in a
consistent and reliable manner by biodegradation of the polymers in
the polymer particles.
[0009] In one embodiment, the invention provides a polymer particle
delivery composition in which at least one bioactive agent is
dispersed in a biodegradable polymer, wherein the polymer is a PEA
having a chemical formula described by structural formula (I),
##STR1## wherein n ranges from about 5 to about 150; R.sup.1 is
independently selected from residues of .mu.,.alpha.,.omega.-bis
(4-carboxyphenoxy)--(C.sub.1-C.sub.8) alkane,
3,3'-(alkanedioyldioxy)dicinnamic acid or 4,4'-(alkanedioyldioxy)
dicinnamic acid, (C.sub.2 - C.sub.20) alkylene, (C.sub.2-C.sub.20)
alkenylene or saturated or unsaturated residues of therapeutic
di-acids; the R.sup.3s in individual n monomers are independently
selected from the group consisting of hydrogen, (C.sub.1-C.sub.6)
alkyl, (C.sub.2-C.sub.6) alkenyl, (C.sub.2-C.sub.6) alkynyl,
(C.sub.6-C .sub.10) aryl (C.sub.1-C.sub.6) alkyl, and
--(CH.sub.2).sub.2S(CH.sub.3),; and R.sup.4 is independently
selected from the group consisting of (C.sub.2-C.sub.20) alkylene,
(C.sub.2-C.sub.20) alkenylene, (C.sub.2-C.sub.8) alkyloxy,
(C.sub.2-C.sub.20) alkylene, bicyclic-fragments of
1,4:3,6-dianhydrohexitols of structural formula (II), and
combinations thereof, (C.sub.2 -C.sub.20) alkylene,
(C.sub.2-C.sub.20) alkenylene, saturated or unsaturated therapeutic
di-acid residues, and combinations thereof; ##STR2## or a PEA
polymer having a chemical formula described by structural formula
III: ##STR3##
[0010] wherein n ranges from about 5 to about 150, m ranges about
0.1 to 0.9: p ranges from about 0.9 to 0.1; wherein R.sup.1 is
independently selected from residues of
.alpha.,.omega.-bis(4-carboxyphenoxy)-(C.sub.1 -C.sub.8) alkane,
3,3'(alkanedioyldioxy)dicinnamic acid or
4,4'(alkanedioyldioxy)dicinnamic acid, (C.sub.2 -C.sub.20)
alkylene, (C.sub.2-C.sub.20) alkenylene or a saturated or
unsaturated residues of therapeutic di-acids; each R.sup.2 is
independently hydrogen, (C.sub.1-C.sub.12) alkyl or
(C.sub.6-C.sub.10) aryl or a protecting group; the R.sup.3s in
individual m monomers are independently selected from the group
consisting of hydrogen, (C.sub.1-C.sub.6) alkyl, (C.sub.2-C.sub.6)
alkenyl, (C.sub.2-C.sub.6) alkynyl, (C.sub.6-C.sub.10) aryl
(C.sub.1-C.sub.6) alkyl,-(CH.sub.2) .sub.2S(CH.sub.2), and
-(CH.sub.2).sub.3; and R.sup.4 is independently selected from the
group consisting of (C.sub.2-C.sub.20) alkylene, (C.sub.2-C.sub.20)
alkenylene, (C.sub.2-C.sub.8) alkyloxy, (C.sub.2-C.sub.20)
alkylene, bicyclic-fragments of 1,4:3,6-dianhydrohexitols of
structural formula(II), and combinations thereof, and residues of
saturated or unsaturated therapeutic diols.
[0011] In another embodiment, the polymer is a PEUR polymer having
a chemical formula described by structural formula (IV), ##STR4##
wherein n ranges from about 5 to about 150; wherein R.sup.3s in
independently selected from the group consisting of hydrogen,
(C.sub.1-C.sub.6) alkyl, (C.sub.2-C.sub.6) alkenyl,
(C.sub.2-C.sub.6) alkynyl, (C.sub.6-C.sub.10) aryl(C.sub.1-C.sub.6)
alkyl, --CH.sub.2).sub.2S(CH.sub.2) and -(CH.sub.2).sub.3; R.sup.4
is selected from the group consisting of (C.sub.2-C.sub.20)
alkylene, (C.sub.2-C.sub.20) alkenylene or alkyloxy, and
bicyclic-fragments of 1,4:3,6-dianhydrohexitols of structural
formula (II); and R.sup.6 is independently selected from
(C.sub.2-C.sub.20) alkylene, (C.sub.2-C.sub.20) alkenylene or
alkyloxy, bicyclic-fragments of 1,4:3,6-dianhydrohexitols of
general formula (II), a residue of a saturated or unsaturated
therapeutic diol, and mixtures thereof.
[0012] or a PEUR polymer having a chemical structure described by
general structural formula (V) ##STR5## wherein n ranges from about
5 to about 150, m ranges about 0.1 to about 0.9: p ranges from
about 0.9 to about 0. 1; R.sup.2 is independently selected from
hydrogen, (C.sub.6-C.sub.10)aryl(C.sub.1-C.sub.6) alkyl, or a
protecting group; the R.sup.3s in an individual m monomer are
independently selected from the group consisting of hydrogen,
(C.sub.1-C.sub.6) alkyl, (C.sub.2-C.sub.6) alkenyl,
(C.sub.2-C.sub.6) alkynyl, (C.sub.6-C.sub.10) aryl(C.sub.1-C.sub.6)
alkyl, -CH.sub.2).sub.3 and -(CH.sub.2).sub.2S(CH.sub.2); R.sup.4
is selected from the group consisting of (C.sub.2-C.sub.20)
alkylene, (C.sub.2-C.sub.20) alkenylene or alkyloxy, and
bicyclic-fragments of 1 ,4:3,6-dianhydrohexitols of structural
formula (II); and R.sup.6 is independently selected from
(C.sub.2-C.sub.20) alkylene, (C.sub.2-C.sub.20) alkenylene or
alkyloxy, bicyclic-fragments of 1,4:3,6-dianhydrohexitols of
general formula (II), a residue of a saturated or unsaturated
therapeutic diol, and mixtures thereof.
[0013] In still another embodiment, the polymer is a biodegradable
PEU polymer having a chemical formula described by general
structural formula (VI): ##STR6## wherein n is about 10 to about
150; each R.sup.3s within an individual n monomer are independently
selected from hydrogen, (C.sub.1,-C.sub.6) alkyl, (C.sub.2-C.sub.6)
alkenyl, (C.sub.2-C.sub.6) alkynyl, (C.sub.6 -C.sub.10) aryl
(C.sub.1-C.sub.6) alkyl, -(CH.sub.2).sub.3, and
-(CH.sub.2).sub.2S(CH.sub.2); R.sup.4 is independently selected
from (C.sub.2-C.sub.20) alkylene, (C.sub.2-C.sub.20) alkenylene,
(C.sub.2-C.sub.8) alkyloxy (C.sub.2-C.sub.20) alkylene, a residue
of a saturated or unsaturated therapeutic diol; or a
bicyclic-fragment of a 1,4:3,6-dianhydrohexitol of structural
formula (II), and mixtures thereof;
[0014] or a PEU having a chemical formula described by structural
formula (VII) ##STR7## wherein m is about 0.1 to about 1.0; p is
about 0.9 to about 0.1; n is about 10 to about 150; each R.sup.2 is
independently hydrogen, (C.sub.1-C.sub.12) alkyl or
(C.sub.6-C.sub.10) aryl; the R.sup.3s within an individual m
monomer are independently selected from hydrogen, (C.sub.1-C.sub.6)
alkyl, (C.sub.2-C.sub.6) alkenyl, (C.sub.2-C.sub.6) alkynyl,
(C.sub.6 -C .sub.10 ) aryl (C.sub.1-C.sub.6)alkyl, -CH.sub.2).sub.3
and -(CH.sub.2).sub.2S(CH.sub.2);; each R.sup.4 is independently
selected from (C.sub.2-C.sub.20) alkylene, (C.sub.2-C.sub.20)
alkenylene, (C.sub.2-C.sub.8) alkyloxy (C.sub.2-C.sub.20) alkylene,
a residue of a saturated or unsaturated therapeutic diol; or a
bicyclic-fragment of a 1,4:3,6-dianhydrohexitol of structural
formula (II), and mixtures thereof.
[0015] In another embodiment, the invention provides
micelle-forming polymer particle delivery compositions for delivery
of bioactive agents dispersed in a biodegradable polymer. In this
embodiment the polymer is made of a hydrophobic section containing
a biodegradable polymer having a chemical structure described by
structural formulas I and III - VII joined to a water soluble
section. The water soluble section is made of at least one block of
ionizable poly(amino acid) , or repeating alternating units of i)
polyethylene glycol, polyglycosaminoglycan, or polysaccharide; and
ii) at least one ionizable or polar amino acid. The repeating
alternating units have substantially similar molecular weights and
the molecular weight of the polymer is in the range from about 10
kD to 300kD.
[0016] In still another embodiment, the invention provides methods
for delivering a bioactive agent to a subject by administering to
the subject in vivo an invention polymer particle delivery
composition containing a polymer of any one of structural formulas
I and III-VII in the form of a liquid dispersion of polymer
particles that incorporate at least one bioactive agent, which
particles biodegrade by enzymatic action to release the bioactive
agent over time.
[0017] In yet another embodiment, the invention provides methods
for delivering polymer particles containing one or more bioactive
agents to a local site in the body in a subject. In this embodiment
the invention methods involve delivering as a dispersion an
invention polymer particle deliver composition, wherein the
particles contain a polymer of any one of structural formulas I and
III-VII to an in vivo site in the body of the subject where the
injected particles agglomerate to form a polymer depot of particles
of increased size.
[0018] In another embodiment, the invention provides methods for
administering a therapeutic diol or di-acid to a subject by
administering to the subject as a dispersion an invention polymer
particle delivery composition containing particles of a polymer of
structural formula I, or III-VII, wherein a residue of therapeutic
diol or di-acid is contained in the polymer backbone, which
composition biodegrades by enzymatic action to release the
therapeutic diol or di-acid over time.
[0019] In yet another embodiment, the invention provides a polymer
composition comprising the co-monomer, bis(.alpha.-amino
acid)-estradiol-3,17.beta.-diester, and salts thereof.
A BRIEF DESCRIPTION OF THE FIGURES
[0020] FIG. 1 is a schematic drawing illustrating a water soluble
covering molecule coating the exterior of a polymer particle.
[0021] FIG. 2 is a schematic drawing illustrating a bioactive agent
coating the exterior of a polymer particle.
[0022] FIG. 3 is a schematic drawing illustrating a water-soluble
polymer coating applied to the exterior of a polymer particle to
which is attaching a bioactive agent.
[0023] FIGS. 4-9 are schematic drawings representing invention
polymer particles with active agents dispersed therein by double
and triple emulsion procedures described herein. Fig.4 shows a
polymer particle encapsulating drug in water formed by double
emulsion technique. FIG. 5 shows a polymer particle formed by
double emulsion in which drops of water in which drug is dissolved
are matrixed within the polymer particle. FIG. 6 shows a polymer
particle formed by a triple emulsion technique in which a drug
dispersed in water is encapsulated within a polymer coating forming
the particle. FIG. 7 shows a polymer particle formed by a triple
emulsion technique in which smaller particles of polymer containing
dispersed drug are matrixed in water and coated with a polymer
coating forming the particle. FIG. 8 shows a polymer particle
formed of drug matrixed in the polymer forming the particle. FIG. 9
shows a drug/first polymer mixture encapsulated within a coating of
a second polymer in which the mixture is not soluble.
[0024] FIG. 10 is a schematic drawing illustrating invention
micelles containing dispersed active agents, as described
herein.
DETAILED DESCRIPTION OF THE INVENTION
[0025] The invention is based on the discovery that biodegradable
polymers can be used to create a polymer particle delivery
composition for in vivo delivery of bioactive agents dispersed
within. The particles biodegrade by enzymatic and hydrolytic
actions so as to release the bioactive agent over time. The
invention compositions are stable, and can be lyophilized for
transportation and storage and be redispersed for administration.
Due to structural properties of the polymer used, the polymer
particle delivery composition provides for high loading of
bioactive agents.
[0026] In one embodiment, the invention provides a polymer particle
delivery composition in which at least one bioactive agent is
dispersed in a biodegradable polymer, wherein the polymer is a PEA
having a chemical formula described by structural formula (I),
##STR8## wherein n ranges from about 5 to about 150; R.sup.1 is
independently selected from residues of .alpha.,.omega.-bis
(4-carboxyphenoxy) (C.sub.1-C.sub.8) alkane,
3,3'(alkanedioyidioxy)dicinnamic acid or
4,4'(alkanedioyldioxy)dicinnamic acid, (C.sub.2 - C.sub.20)
alkylene, (C.sub.2-C.sub.20) alkenylene or a saturated or
unsaturated residues of therapeutic di-acids; the R.sup.3s in
individual n monomers are independently selected from the group
consisting of hydrogen, ethylene amide, (C.sub.1-C.sub.6) alkyl,
(C.sub.2-C.sub.6) alkenyl, (C.sub.2-C.sub.6) alkynyl,
(C.sub.6-C.sub.10) aryl (C.sub.1-C.sub.6) alkyl, -CH.sub.2).sub.3,
and -(CH.sub.2).sub.2S(CH.sub.2); and R.sup.4 is independently
selected from the group consisting of (C.sub.2-C.sub.20) alkylene,
(C.sub.2-C.sub.20) alkenylene, (C.sub.2-C.sub.8) alkyloxy,
(C.sub.2-C.sub.20) alkylene, bicyclic-fragments of
1,4:3,6-dianhydrohexitols of structural formula (II), and
combinations thereof, (C.sub.2 - C.sub.20) alkylene,
(C.sub.2-C.sub.20) alkenylene, and saturated or unsaturated
therapeutic di-acid residues; ##STR9## or a PEA polymer having a
chemical formula described by structural formula III: ##STR10##
wherein n ranges from about 5 to about 150, m ranges about 0.1 to
0.9: p ranges from about 0.9 to 0.1; wherein R.sup.1is
independently selected from residues of .alpha.,.omega.)-bis
(4-carboxyphenoxy) (C.sub.1-C.sub.8) alkane,
3,3'(alkanedioyldioxy)dicinnamic acid or
4,4'(alkanedioyldioxy)dicinnamic acid, (C.sub.2 - C.sub.20)
alkylene, (C.sub.2-C.sub.20) alkenylene or a saturated or
unsaturated residues of therapeutic di-acids; each R.sup.2 is
independently hydrogen, (C.sub.1-C.sub.12) alkyl or
(C.sub.6-C.sub.10) aryl or a protecting group; the R.sup.3s in
individual m monomers are independently selected from the group
consisting of hydrogen, (C.sub.1-C.sub.6) alkyl, (C.sub.2-C.sub.6)
alkenyl, (C.sub.2-C.sub.6) alkynyl, (C.sub.6-C.sub.10 ) aryl
(C.sub.2-C.sub.6) alkyl, -CH.sub.2).sub.3, and
-(CH.sub.2).sub.2S(CH.sub.2); and R.sup.4 is independently selected
from the group consisting of (C.sub.2-C.sub.20) alkylene,
(C.sub.2-C.sub.20) alkenylene, (C.sub.2-C.sub.8) alkyloxy,
(C.sub.2-C.sub.20) alkylene, bicyclic-fragments of
1,4:3,6-dianhydrohexitols of structural formula (II), and
combinations thereof, and residues of saturated or unsaturated
therapeutic diols.
[0027] For example, an effective amount of the residue of at least
one therapeutic diol or di-acid can be contained in the polymer
backbone. Alternatively, in the PEA polymer, at least one R.sup.1is
a residue of .alpha.,.omega.-bis (4-carboxyphenoxy)
(C.sub.1-C.sub.8) alkane or 4,4'(alkanedioyldioxy)dicinnamic acid
and R.sup.4 is a bicyclic-fragment of a 1,4:3,6-dianhydrohexitol of
general formula (II), or a residue of a saturated or unsaturated
therapeutic diol. In another alternative, R.sub.1in the PEA polymer
is either a residue of .alpha.,.omega.-bis (4-carboxyphenoxy)
(C.sub.1-C.sub.8) alkane, or 4,4'(alkanedioyldioxy)dicinnamic acid,
a residue of a therapeutic diacid, and mixtures thereof. In yet
another alternative, in the PEA polymer R.sup.1is a residue
.alpha.,.omega.-bis (4-carboxyphenoxy) (C.sub.1-C.sub.8) alkane,
such as 1,3-bis(4-carboxyphenoxy)propane (CPP), or 4,4'
(alkanedioyldioxy)dicinnamic acid and R.sup.4 is a
bicyclic-fragment of a 1,4:3,6-dianhydrohexitol of general formula
(II), such as 1,4:3,6-dianhydrosorbitol (DAS).
[0028] Alternatively, the invention provides a polymer particle
delivery composition in which a therapeutically effective amount of
at least one bioactive agent is dispersed in a biodegradable
polymer, wherein the polymer is a PEUR polymer having a chemical
formula described by structural formula (IV), ##STR11## and wherein
n ranges from about 5 to about 150; wherein the R.sup.3s within an
individual n monomer are independently selected from the group
consisting of hydrogen, (C.sub.1-C.sub.6) alkyl, (C.sub.2-C.sub.6)
alkenyl, (C.sub.2-C.sub.6) alkynyl, (C.sub.6-C.sub.10 )
aryl(C.sub.1-C.sub.6) alkyl, --CH.sub.2).sub.3, and
--CH.sub.2).sub.2S(CH.sub.2); R.sup.4 is selected from the group
consisting of (C.sub.2-C.sub.20) alkylene, (C.sub.2-C.sub.20)
alkenylene or alkyloxy, and bicyclic-fragments of 1
,4:3,6-dianhydrohexitols of structural formula (II); and R.sup.6 is
independently selected from (C.sub.2-C.sub.20) alkylene,
(C.sub.2-C.sub.20) alkenylene or alkyloxy, bicyclic-fragments of
1,4:3,6-dianhydrohexitols of general formula (II), a residue of a
saturated or unsaturated therapeutic diol, and mixtures thereof. or
a PEUR polymer having a chemical structure described by general
structural formula (V) ##STR12## wherein n ranges from about 5 to
about 150, m ranges about 0.1 to about 0.9: p ranges from about 0.9
to about 0.1; R.sup.2 is independently selected from hydrogen,
(C.sub.6-C.sub.10)aryl(C.sub.1-C.sub.6) alkyl, or a protecting
group; the R.sup.3s within an individual m monomer are
independently selected from the group consisting of hydrogen,
(C.sub.1-C.sub.6) alkyl, (C.sub.2-C.sub.6) alkenyl,
(C.sub.2-C.sub.6) alkynyl, (C.sub.6-C.sub.10 )
aryl(C.sub.1-C.sub.6) alkyl, -(CH.sub.2).sub.3, and
-(CH.sub.2).sub.2S(CH.sub.2); R.sup.4 is selected from the group
consisting of (C.sub.2-C.sub.20) alkylene, (C.sub.2-C.sub.20)
alkenylene or alkyloxy, and bicyclic-fragments of
1,4:3,6-dianhydrohexitols of structural formula (II); and R.sup.6
is independently selected from (C.sub.2-C.sub.20) alkylene,
(C.sub.2-C.sub.20) alkenylene or alkyloxy, bicyclic-fragments of
1,4:3,6-dianhydrohexitols of structural formula (II), a residue of
a saturated or unsaturated therapeutic diol, and mixtures
thereof.
[0029] For example, an effective amount of the residue of at least
one therapeutic diol can be contained in the polymer backbone. In
one alternative in the PEUR polymer, at least one of R.sup.4 or
R.sup.6 is a bicyclic fragment of 1,4:3,6-dianhydrohexitol, such as
1,4:3,6-dianhydrosorbitol (DAS).
[0030] In still another embodiment the invention provides a polymer
particle delivery composition in which a therapeutically effective
amount of at least one bioactive agent is dispersed in a
biodegradable polymer, wherein the polymer is a biodegradable PEU
polymer having a chemical formula described by structural formula
(VI): ##STR13## wherein n is about 10 to about 150; the R.sup.3s
within an individual n monomer are independently selected from
hydrogen, (C.sub.1 -C.sub.6) alkyl, (C.sub.2-C.sub.6) alkenyl,
(C.sub.2-C.sub.6) alkynyl, (C.sub.6 -C.sub.10) aryl
(C.sub.1-C.sub.6) alkyl, --(CH.sub.2).sub.3, and
-CH.sub.2).sub.2S(CH.sub.2); R.sup.4 is independently selected from
(C.sub.2-C.sub.20) alkylene, (C.sub.2-C.sub.20) alkenylene,
(C.sub.2-C.sub.8) alkyloxy (C.sub.2-C.sub.20) alkylene, a residue
of a saturated or unsaturated therapeutic diol; or a
bicyclic-fragment of a 1,4:3,6-dianhydrohexitol of structural
formula (II);
[0031] or structural formula (VII) ##STR14## wherein m is about 0.1
to about 1.0; p is about 0.9 to about 0. 1; n is about 10 to about
150; each R2 is independently hydrogen, (C.sub.1-C.sub.12) alkyl or
(C.sub.6- C.sub.10) aryl; and the R.sup.3s within an individual m
monomer are independently selected from hydrogen,
(C.sub.1-C.sub.1C.sub.6) alkyl, (C.sub.2-C.sub.6) alkenyl,
(C.sub.2-C.sub.6) alkynyl, (C.sub.6 -C.sub.10) aryl
(C.sub.1C.sub.6)alkyl, -C.sub.2).sub.3, and
-(CH.sub.2)C.sub.2S(CH.sub.2); R.sup.4 is independently selected
from (C.sub.2-C.sub.20) alkylene, (C.sub.2-C.sub.20) alkenylene,
(C.sub.2-C.sub.8) alkyloxy (C.sub.2-C.sub.20) alkylene, a residue
of a saturated or unsaturated therapeutic diol; or a
bicyclic-fragment of a 1 ,4:3,6-dianhydrohexitol of structural
formula (II), or a mixture thereof.
[0032] For example, an effective amount of the residue of at least
one therapeutic diol can be contained in the polymer backbone. In
one alternative in the PEU polymer, at least one R.sup.4 is a
residue of a saturated or unsaturated therapeutic diol, or a
bicyclic fragment of a 1,4:3,6-dianhydrohexitol, such as DAS. In
yet another alternative in the PEU polymer, at least one R.sup.4 is
a bicyclic fragment of a 1,4:3,6-dianhydrohexitol, such as DAS.
[0033] These PEU polymers can be fabricated as high molecular
weight polymers useful for making the invention polymer particle
delivery compositions for delivery to humans and other mammals of a
variety of pharmaceutical and biologically active agents. The
invention PEUs incorporate hydrolytically cleavable ester groups
and non-toxic, naturally occurring monomers that contain
.alpha.-amino acids in the polymer chains. The ultimate
biodegradation products of PEUs will be amino acids, diols, and
CO.sub.2. In contrast to the PEAs and PEURs, the invention PEUs are
crystalline or semi-crystalline and possess advantageous
mechanical, chemical and biodegradation properties that allow
formulation of completely synthetic, and hence easy to produce,
crystalline and semi-crystalline polymer particles, for example
nanoparticles. For example, the PEU polymers used in the invention
polymer particle delivery compositions have high mechanical
strength, and surface erosion of the PEU polymers can be catalyzed
by enzymes present in physiological conditions, such as
hydrolases.
[0034] As used herein, the terms "amino acid" and ".alpha.-amino
acid" mean a chemical compound containing an amino group, a
carboxyl group and a pendent R group, such as the R.sup.3 groups
defined herein. As used herein, the term "biological .alpha.-amino
acid" means the amino acid(s) used in synthesis are selected from
phenylalanine, leucine, glycine, alanine, valine, isoleucine,
methionine, or a mixture thereof.
[0035] As used herein, a "therapeutic diol" means any diol
molecule, whether synthetically produced, or naturally occurring
(e.g., endogenously) that affects a biological process in a
mammalian individual, such as a human, in a therapeutic or
palliative manner when administered to the mammal.
[0036] As used herein, the term "residue of a therapeutic diol"
means a portion of a therapeutic diol, as described herein, which
portion excludes the two hydroxyl groups of the diol. As used
herein, the term "residue of a therapeutic di-acid" means a portion
of a therapeutic di-acid, as described herein, which portion
excludes the two carboxyl groups of the di-acid. The corresponding
therapeutic diol or di-acid containing the "residue" thereof is
used in synthesis of the polymer compositions. The residue of the
therapeutic di-acid or diol is reconstituted in vivo (or under
similar conditions of pH, aqueous media, and the like) to the
corresponding di-acid or diol upon release from the backbone of the
polymer by biodegradation in a controlled manner that depends upon
the properties of the PEA, PEUR or PEU polymer selected to
fabricate the composition, which properties are as known in the art
and as described herein.
[0037] As used herein the term "bioactive agent" means a bioactive
agent as disclosed herein that is not incorporated into the polymer
backbone. One or more such bioactive agents may be included in the
invention therapeutic polymers. As used herein, the term
"dispersed" is used to refer to additional bioactive agents and
means that the additional bioactive agent is dispersed, mixed,
dissolved, homogenized, and/or covalently bound ("dispersed") in a
polymer, for example attached to a functional group in the
therapeutic polymer of the composition or to the surface of a
polymer particle, but not incorporated into the backbone of a PEA,
PEUR, or PEU polymer. To distinguish backbone-incorporated
therapeutic diols and di-acids from those that are not incorporated
into the polymer backbone, (as a residue thereof), such dispersed
therapeutic or palliative agents are referred to herein as
"bioactive agent(s)" and may be contained within polymer conjugates
or otherwise dispersed in the polymer particle composition, as
described below. Such bioactive agents may include, without
limitation, small molecule drugs, peptides, proteins, DNA, cDNA,
RNA, sugars, lipids and whole cells. The bioactive agents are
administered in polymer particles having a variety of sizes and
structures suitable to meet differing therapeutic goals and routes
of administration.
[0038] The term, "biodegradable, biocompatible" as used herein to
describe the invention polymer particle delivery compositions means
the polymer used therein is capable of being broken down into
innocuous products in the normal functioning of the body. This is
particularly true when the amino acids used in fabrication of the
invention polymers are biological L-.alpha.-amino acids. The
polymers in the invention polymer particle delivery compositions
include hydrolyzable ester and enzymatically cleavable amide
linkages that provide biodegradability, and are typically chain
terminated, predominantly with amino groups. Optionally, the amino
termini of the polymers can be acetylated or otherwise capped by
conjugation to any other acid-containing, biocompatible molecule,
to include without restriction organic acids, bioinactive
biologics, and bioactive agents as described herein. In one
embodiment, the entire polymer composition, and any particles made
thereof, is substantially biodegradable.
[0039] In one alternative, at least one of the ax-amino acids used
in fabrication of the invention polymers is a biological
.alpha.-amino acid. For example, when the R.sup.3s are CH.sub.2Ph,
the biological .alpha.-amino acid used in synthesis is
L-phenylalanine. In alternatives wherein the R.sup.3s are CH
.sub.2-CH(CHC.sub.3)C.sub.2, the polymer contains the biological
.alpha.-amino acid, L-leucine. By varying the R.sup.3s within
monomers as described herein, other biological 0:.alpha.-amino
acids can also be used, e.g., glycine (when the R.sup.3s are H),
alanine (when the R.sup.3s are CH.sub.3), valine (when the R.sup.3s
are CH(CH 3)C.sub.2), isoleucine (when the R.sup.3s are
CH(CH.sub.3)--CH.sub.2--CH.sub.3), phenylalanine (when the R.sup.3s
are CH.sub.2-C.sub.6H.sub.5), or methionine (when the R.sup.3s are
-(CH.sub.2)C.sub.2SCH.sub.3), and mixtures thereof. In yet another
alternative embodiment, all of the various .alpha.amino acids
contained in the polymers used in making the invention polymer
particle delivery compositions are biological .alpha.-amino acids,
as described herein.
[0040] The term, "biodegradable" as used herein to describe the
polymers used in the invention polymer particle delivery
compositions means the polymer is capable of being broken down into
innocuous and bioactive products in the normal functioning of the
body. In one embodiment, the entire polymer particle delivery
composition is biodegradable. The biodegradable polymers described
herein have hydrolyzable ester and enzymatically cleavable amide
linkages that provide the biodegradability, and are typically chain
terminated predominantly with amino groups. Optionally, these amino
termini can be acetylated or otherwise capped by conjugation to any
other acid-containing, biocompatible molecule, to include without
restriction organic acids, bioinactive biologics and bioactive
compounds such as adjuvant molecules.
[0041] The polymer particle delivery compositions can be formulated
to provide a variety of properties. In one embodiment, the polymer
particles are sized to agglomerate in vivo forming a time-release
polymer depot for local delivery of dispersed bioactive agents to
surrounding tissue/cells when injected in vivo, for example
subcutaneously, intramuscularly, or into an interior body site,
such as an organ. For example, invention polymer particles of sizes
capable of passing through pharmaceutical syringe needles ranging
in size from about 19 to about 27 Gauge, for example those having
an average diameter in the range from about 1 .mu.m to about 200
.mu.m, can be injected into an interior body site, and will
agglomerate to form particles of increased size that form the depot
to dispense the bioactive agent(s) locally. In other embodiments,
the biodegradable polymer particles act as a carrier for the
bioactive agent into the circulation for targeted and timed release
systemically. Invention polymer particles in the size range of
about 10 nm to about 500 nm will enter directly into the
circulation for such purposes.
[0042] The biodegradable polymers used in the invention polymer
particle delivery composition can be designed to tailor the rate of
biodegradation of the polymer to result in continuous delivery of
the bioactive agent over a selected period of time. For instance,
typically, a polymer depot, as described herein, will biodegrade
over a time selected from about twenty-four hours, about seven
days, about thirty days, or about ninety days, or longer. Longer
time spans are particularly suitable for providing a delivery
composition that eliminates the need to repeatedly inject the
composition to obtain a suitable therapeutic or palliative
response.
[0043] The present invention utilizes biodegradable polymer
particle-mediated delivery techniques to deliver a wide variety of
bioactive agents in treatment of a wide variety of diseases and
disease symptoms. Although certain of the individual components of
the polymer particle delivery composition and methods described
herein were known, it was unexpected and surprising that such
combinations would enhance the efficiency of time release delivery
of the bioactive agents beyond levels achieved when the components
were used separately.
[0044] Polymers suitable for use in the practice of the invention
bear functionalities that allow facile covalent attachment of the
bioactive agent(s) or covering molecule(s) to the polymer. For
example, a polymer bearing carboxyl groups can readily react with
an amino moiety, thereby covalently bonding a peptide to the
polymer via the resulting amide group. As will be described herein,
the biodegradable polymer and the bioactive agent may contain
numerous complementary functional groups that can be used to
covalently attach the bioactive agent to the biodegradable
polymer.
[0045] The polymer in the invention polymer particle delivery
composition plays an active role in the treatment processes at the
site of local injection by holding the bioactive agent at the site
of injection for a period of time sufficient to allow the
individual's endogenous processes to interact with the bioactive
agent, while slowly releasing the particles or polymer molecules
containing such agents during biodegradation of the polymer. The
fragile bioactive agent is protected by the more slowly
biodegrading polymer to increase half-life and persistence of the
bioactive agent(s).
[0046] In addition, the polymers disclosed herein (e.g., those
having structural formulas (I and III-VII), upon enzymatic
degradation, provide amino acids while the other breakdown products
can be metabolized in the way that fatty acids and sugars are
metabolized. Uptake of the polymer with bioactive agent is safe:
studies have shown that the subject can metabolize/clear the
polymer degradation products. These polymers and the invention
polymer particle delivery compositions are, therefore,
substantially non-inflammatory to the subject both at the site of
injection and systemically, apart from the trauma caused by
injection itself.
[0047] The biodegradable polymers useful in forming the invention
biocompatible polymer particle delivery compositions include those
comprising at least one amino acid conjugated to at least one
non-amino acid moiety per repeat unit. In the PEA, PEUR and PEU
polymers useful in practicing the invention, multiple different
.alpha.-amino acids can be employed in a single polymer molecule.
The term "non-amino acid moiety" as used herein includes various
chemical moieties, but specifically excludes amino acid derivatives
and peptidomimetics as described herein. In addition, the polymers
containing at least one amino acid are not contemplated to include
poly(amino acid) segments, including naturally occurring
polypeptides, unless specifically described as such. In one
embodiment, the non-amino acid is placed between two adjacent
.alpha.-aminq acids in the repeat unit. The polymers may comprise
at least two different amino acids per repeat unit and a single
polymer molecule may contain multiple different .alpha.-amino acids
in the polymer molecule, depending upon the size of the molecule.
In another embodiment, the non-amino acid moiety is hydrophobic.
The polymer may also be a block co-polymer. In another embodiment,
the polymer is used as one block in di- or tri-block copolymers,
which are used to make micelles, as described below.
[0048] Preferred for use in the invention polymer particle delivery
compositions and methods are polyester amides (PEAs), polyester
urethanes (PEURs) and polyester ureas (PEUs), many of which have
built-in functional groups on PEA, PEUR or PEU side chains, and
these built-in functional groups can react with other chemicals and
lead to the incorporation of additional functional groups to expand
the functionality of the polymers further. Therefore, such polymers
used in the invention methods are ready for reaction with other
chemicals having a hydrophilic structure to increase water
solubility and with bioactive agents and covering molecules,
without the necessity of prior modification.
[0049] In addition, the polymers used in the invention polymer
particle delivery compositions display minimal hydrolytic
degradation when tested in a saline (PBS) medium, but in an
enzymatic solution, such as chymotrypsin or CT, a uniform erosive
behavior has been observed.
[0050] Suitable protecting groups for use in the PEA, PEUR and PEU
polymers include t-butyl or another as is known in the art.
Suitable 1 ,4:3,6-dianhydrohexitols of general formula(II) include
those derived from sugar alcohols, such as D-glucitol, D-mannitol,
or L-iditol. Dianhydrosorbitol is the presently preferred bicyclic
fragment of a 1 ,4:3,6-dianhydrohexitol for use in the PEA, PEUR
and PEU polymers used in fabrication of the invention polymer
particle delivery compositions.
[0051] The PEA, PEUR and PEU polymer molecules may also have the
active agent attached thereto, optionally via a linker or
incorporated into a crosslinker between molecules. For example, in
one embodiment, the polymer is contained in a polymer-bioactive
agent conjugate having structural formula VIII: ##STR15## wherein
n, m, p, R.sup.1, R.sup.3, and R.sup.4 are as above, R.sup.5 is
selected from the group consisting of --O-, -S-, and -NR.sup.8-,
wherein R.sup.8 is H or (C.sub.1-C.sub.8)alkyl; and R.sup.7 is the
bioactive agent.
[0052] In yet another embodiment, two molecules of the polymer of
structural formula (IX) can be crosslinked to provide an
-R.sup.5-R.sup.7-R.sup.5-conjugate. In another embodiment, as shown
in structural formula IX below, the bioactive agent is covalently
linked to two parts of a single polymer molecule of structural
formula IV through the -R.sup.5-R.sup.7-R.sup.5-conjugate and R
.sup.5is independently selected from the group consisting of --O-,
-S-, and -NR.sup.8-, wherein R.sup.8 is H or (C.sub.1,-C.sub.8)
alkyl; and R.sup.7 is the bioactive agent. ##STR16##
[0053] Alternatively still, as shown in structural formula (X)
below, a linker, --X-Y-, can be inserted between R.sup.5 and
bioactive agent R.sup.7, in the molecule of structural formula
(IV), wherein X is selected from the group consisting of
(C.sub.1-C.sub.18) alkylene, substituted alkylene,
(C.sub.3-C.sub.8) cycloalkylene, substituted cycloalkylene, 5-6
membered heterocyclic system containing 1-3 heteroatoms selected
from the group O, N, and S, substituted heterocyclic,
(C.sub.2-C.sub.18) alkenyl, substituted alkenyl, alkynyl,
substituted alkynyl, C.sub.6 and C.sub.10 aryl, substituted aryl,
heteroaryl, substituted heteroaryl, alkylaryl, substituted
alkylaryl, arylalkynyl, substituted arylalkynyl, arylalkenyl,
substituted arylalkenyl, arylalkynyl, substituted arylalkynyl and
wherein the substituents are selected from the group H, F, Cl, Br,
I, (C.sub.1-C.sub.6) alkyl, -CN, -NO.sub.2, -OH, -O(C.sub.1
-C.sub.4) alkyl, -S(C.sub.1-C.sub.6) alkyl,
-S[(=O)(C.sub.1-C.sub.6) alkyl], -S[(O .sub.2)(C.sub.1-C.sub.6)
alkyl], -C[(=O)(C.sub.1-C.sub.6) alkyl], CF.sub.3,-O
[(CO)-(C.sub.1-C.sub.6) alkyl], -S(O.sub.2)[N(R.sup.9R.sup.10)],
-NH[(C=O)(C.sub.1-C.sub.6) alkyl], -NH(C=O)N(R.sup.9R.sup.10),
-N(R.sup.9R.sup.10); where R.sup.9 and R.sup.10 are independently H
or (C.sub.1-C.sub.6) alkyl; and Y is selected from the group
consisting of -O-, -S-, -S-S-, -S(O)-,-S(O.sub.2)-, -NR.sup.8-,
-C(=O)-,OC (=O)-, -C(=O)O-, -OC(=O)NH-, -NR.sup.8C(=O)-,
-C(=O)NR.sup.8-, -N R.sup.8C(=O)NR.sup.8-, -N
R.sup.8C(=O)NR.sup.8-, and -NR.sup.8 (=S)N R.sup.8-. ##STR17##
[0054] In another embodiment, two parts of a single macromolecule
are covalently linked to the bioactive agent through an
-R.sup.5-R.sup.7-Y-X-R.sup.5- bridge (Formula XI): ##STR18##
wherein, X is selected from the group consisting of
(C.sub.1-C.sub.1C.sub.8) alkylene, substituted alkylene,
(C.sub.3-C.sub.8) cycloalkylene, substituted cycloalkylene, 5-6
membered heterocyclic system containing 1-3 heteroatoms selected
from the group O, N, and S, substituted heterocyclic,
(C.sub.2-C.sub.8) alkenyl, substituted alkenyl, alkynyl,
substituted alkynyl, (C.sub.6 -C.sub.10) aryl, substituted aryl,
heteroaryl, substituted heteroaryl, alkylaryl, substituted
alkylaryl, arylalkynyl, substituted arylalkynyl, arylalkenyl,
substituted arylalkenyl, arylalkynyl, substituted arylalkynyl,
wherein the substituents are selected from the group consisting of
H, F, Cl, Br, I, (C.sub.1-C.sub.6) alkyl, -CN, -NO.sub.2, -OH,
-O(C.sub.1-C.sub.6) alkyl, -S(C.sub.1-C.sub.6) alkyl,
-S[(=O)(C.sub.1-C.sub.6) alkyl], -S[(O.sub.2)(C.sub.1-C.sub.6)
alkyl], -C[(=O)(C.sub.1-C.sub.6) alkyl],
CF.sub.3,-O[(CO)-(C.sub.1-C.sub.6) alkyl], -S(O.sub.2)[N(R.sup.9
R.sup.10)], -NH[(C=O)(C.sub.1-C.sub.6) alkyl],
-NH(C=O)N(R.sup.9R.sup.10), wherein R.sup.9 and R.sup.10 are
independently H or (C.sub.1-C.sub.6) alkyl, and -N
(R.sup.11R.sup.12), wherein R .sup.11 and R.sup.12 are
independently selected from (C.sub.2-C.sub.20) alkylene and
(C.sub.2-C.sub.20) alkenylene.
[0055] In yet another embodiment, the polymer particle delivery
composition contains four molecules of the polymer, except that
only two of the four molecules omit R.sup.7 and are crosslinked to
provide a single -R.sup.5-X-R.sup.5-conjugate.
[0056] The term "aryl" is used with reference to structural
formulae herein to denote a phenyl radical or an ortho-flised
bicyclic carbocyclic radical having about nine to ten ring atoms in
which at least one ring is aromatic. In certain embodiments, one or
more of the ring atoms can be substituted with one or more of
nitro, cyano, halo, trifluoromethyl, or trifluoromethoxy. Examples
of aryl include, but are not limited to, phenyl, naphthyl, and
nitrophenyl.
[0057] The term "alkenylene" is used with reference to structural
formulae herein to mean a divalent branched or unbranched
hydrocarbon chain containing at least one unsaturated bond in the
main chain or in a side chain.
[0058] The molecular weights and polydispersities herein are
determnined by gel permeation chromatography (GPC) using
polystyrene standards. More particularly, number and weight average
molecular weights (M.sub.n and M.sup.w) are determined, for
example, using a Model 510 gel permeation chromatography (Water
Associates, Inc., Milford, MA) equipped with a high-pressure liquid
chromatographic pump, a Waters 486 UV detector and a Waters 2410
differential refractive index detector. Tetrahydrofuran (THF),
N,N-dimethylformamide (DMF) or N,N-dimethylacetamide (DMAc) is used
as the eluent (1.0 mL/min). Polystyrene or poly(methyl
methacrylate) standards having narrow molecular weight distribution
were used for calibration.
[0059] Methods for making polymers of structural formulas
containing a a-amino acid in the general formula are well known in
the art. For example, for the embodiment of the polymer of
structural formula (I) wherein R.sup.4 is incorporated into an
.alpha.-amino acid, for polymer synthesis the .alpha.-amino acid
with pendant R.sup.3 can be converted through esterification into a
bis-.alpha.,.omega.-diamine, for example, by condensing the a-amino
acid containing pendant R.sup.3 with a diol HO-R.sup.4-OH. As a
result, di-ester monomers with reactive .alpha.,.omega.-amino
groups are formed. Then, the bis-.alpha.,.omega.-diamine is entered
into a polycondensation reaction with a di-acid such as sebacic
acid, or bis-activated esters, or bis-acyl chlorides, to obtain the
final polymer having both ester and amide bonds (PEA).
Alternatively, for example, for polymers of structure (I), instead
of the di-acid, an activated di-acid derivative, e.g.,
bis-para-nitrophenyl diester, can be used as an activated di-acid.
Additionally, a bis-di-carbonate, such as bis(p-nitrophenyl)
dicarbonate, can be used as the activated species to obtain
polymers containing a residue of a di-acid. In the case of PEUR
polymers, a final polymer is obtained having both ester and
urethane bonds.
[0060] More particularly, synthesis of the unsaturated
poly(ester-amide)s (UPEAs) useful as biodegradable polymers of the
structural formula (I) as disclosed above will be described,
wherein ##STR19## and/or (b) R.sup.4 is --CH
.sub.2-CH=CH-CH.sub.2-. In cases where (a) is present and (b) is
not present, R.sup.4 in (I) is -C.sub.4H.sub.8-
or-C.sub.6H.sub.12-. In cases where (a) is not present and (b) is
present, R.sup.1in (I) is -C.sub.4H.sub.8-or
--C.sub.8H.sub.16-.
[0061] The UPEAs can be prepared by solution polycondensation of
either (1) di-p-toluene sulfonic acid salt of bis(.alpha.-amino
acid) di-ester of unsaturated diol and di-p-nitrophenyl ester of
saturated dicarboxylic acid or (2) di-p-toluene sulfonic acid salt
of bis (.alpha.amino acid) diester of saturated diol and
di-nitrophenyl ester of unsaturated dicarboxylic acid or (3)
di-p-toluene sulfonic acid salt of bis(.alpha.-amino acid) diester
of unsaturated diol and di-nitrophenyl ester of unsaturated
dicarboxylic acid.
[0062] Salts of p-toluene sulfonic acid are known for use in
synthesizing polymers containing amino acid residues. The aryl
sulfonic acid salts are used instead of the free base because the
aryl sulfonic salts of bis (.alpha.amino acid) diesters are easily
purified through recrystallization and render the amino groups as
unreactive ammonium tosylates throughout workup. In the
polycondensation reaction, the nucleophilic amino group is readily
revealed through the addition of an organic base, such as
triethylamine, so the polymer product is obtained in high
yield.
[0063] For polymers of structural formula (I), for example, the
di-p-nitrophenyl esters of unsaturated dicarboxylic acid can be
synthesized from p-nitrophenyl and unsaturated dicarboxylic acid
chloride, e.g., by dissolving triethylamine and p-nitrophenol in
acetone and adding unsaturated dicarboxylic acid chloride dropwise
with stirring at -78.degree. C. and pouring into water to
precipitate product. Suitable acid chlorides included fumaric,
maleic, mesaconic, citraconic, glutaconic, itaconic, ethenyl-butane
dioic and 2-propenyl-butanedioic acid chlorides. For polymers of
structure (IV) and (V), bis-p-nitrophenyl dicarbonates of saturated
or unsaturated diols are used as the activated monomer. Dicarbonate
monomers of general structure (XII) are employed for polymers of
structural formula (IV) and (V), ##STR20## wherein each R.sup.5 is
independently (C.sub.6 -C.sub.10) aryl optionally substituted with
one or more nitro, cyano, halo, trifluoromethyl, or
trifluoromethoxy; and R.sup.6 is independently (C.sub.2 -C.sub.20)
alkylene or (C.sub.2-C.sub.20) alkyloxy, or (C.sub.2-C.sub.20)
alkenylene.
[0064] Suitable therapeutic diol compounds that can be used to
prepare bis(.alpha.-amino acid) diesters of therapeutic diol
monomers, or bis(carbonate) of therapeutic di-acid monomers, for
introduction into the invention therapeutic polymer compositions
include naturally occurring therapeutic diols, such as
17-.beta.-estradiol, a natural and endogenous hormone, useful in
preventing restenosis and tumor growth (Yang, N.N.,et al.
Identification of an estrogen response element activated by
metabolites of 17-.beta.-estradiol and raloxifene. Science (1996)
273, 1222-1225; Parangi, S., et al., Inhibition of angiogenesis and
breast cancer in mice by the microtubule inhibitors
2-methoxyestradiol and taxol, Cancer Res. (1997) 57, 81-86; and
Fotsis, T., et al., The endogenous oestrogen metabolite
2-methoxyoestradiol inhibits angiogenesis and suppresses tumor
growth. Nature (1994) .sup.368, 237-239). The safety profiles of
such endogenously occurring therapeutic diol molecules are believed
to be superior to those of synthetic and/or non-endogenous
molecules having a similar utility, such as sirolimus.
[0065] Incorporation of a therapeutic diol into the backbone of a
PEA, PEUR or PEU polymer is illustrated in this application by
Example 8, in which active steroid hormone 17-,.beta.-estradiol
containing mixed hydroxyls-secondary and phenolic-is introduced
into the backbone of a PEA polymer. When the PEA polymer is used to
fabricate particles and the particles are implanted into a patient,
for example, following percutaneous transluminal coronary
angioplasty (PTCA), 17-.beta.-estradiol released from the particles
in vivo can help to prevent post-implant restenosis in the patient.
1 7-.beta.-estradiol, however, is only one example of a diol with
therapeutic properties that can be incorporated in the backbone of
a PEA, PEUR or PEU polymer in accordance with the invention. In one
aspect, any bioactive steroid-diol containing primary, secondary or
phenolic hydroxyls can be used for this purpose. Many steroid
esters that can be made from bioactive steroid diols for use in the
invention are disclosed in European application EP 0127 829 A2.
[0066] Due to the versatility of the PEA, PEUR and PEU polymers
used in the invention compositions, the amount of the therapeutic
diol or di-acid incorporated in the polymer backbone can be
controlled by varying the proportions of the building blocks of the
polymer. For example, depending on the composition of the PEA,
loading of up to 40% w/w of 17.beta.-estradiol can be achieved.
Three different regular, linear PEAs with various loading ratios of
17.beta.-estradiol are illustrated in Scheme 1 below: ##STR21##
Similarly, the loading of the therapeutic diol into PEUR and PEU
polymer can be varied by varying the amount of two or more building
blocks of the polymer. Synthesis of a PEUR containing 1
7-beta-estradiol is illustrated in Example 9 below.
[0067] In addition, synthetic steroid based diols based on
testosterone or cholesterol, such as 4-androstene-3, 17 diol
(4-Androstenediol), 5-androstene-3, 17 diol (5-Androstenediol), 19-
nor5-androstene-3, 17 diol (19-Norandrostenediol) are suitable for
incorporation into the backbone of PEA and PEUR polymers according
to this invention. Moreover, therapeutic diol compounds suitable
for use in preparation of the invention polymer particle delivery
compositions include, for example, amikacin; amphotericin B;
apicycline; apramycin; arbekacin; azidamfenicol; bambermycin(s);
butirosin; carbomycin; cefpiramide; chloramphenicol;
chlortetracycline; clindamycin; clomocycline; demeclocycline;
diathymosulfone; dibekacin, dihydrostreptomycin; dirithromycin;
doxycycline; erythromycin; fortimicin(s); gentamycin(s);
glucosulfone solasulfone; guamecycline; isepamicin; josamycin;
kanamycin(s); leucomycin(s); lincomycin; lucensomycin; lymecycline;
meclocycline; methacycline; micronomycin; midecamycin(s);
minocycline; mupirocin; natamycin; neomycin; netilmicin;
oleandomycin; oxytetracycline; paromycin; pipacycline;
podophyllinic acid 2-ethylhydrazine; primycin; ribostamycin;
rifamide; rifampin; rafamycin SV; rifapentine; rifaximin;
ristocetin; rokitamycin; rolitetracycline; rasaramycin;
roxithromycin; sancycline; sisomicin; spectinomycin; spiramycin;
streptomycin; teicoplanin; tetracycline; thiamphenicol;
theiostrepton; tobramycin; trospectomycin; tuberactinomycin;
vancomycin; candicidin(s); chlorphenesin; dermostatin(s); filipin;
fungichromin; kanamycin(s); leucomycins(s); lincomycin;
lvcensomycin; lymecycline; meclocycline; methacycline;
micronomycin; midecamycin(s); minocycline; mupirocin; natamycin;
neomycin; netilmicin; oleandomycin; oxytetracycline; paramomycin;
pipacycline; podophyllinic acid 2-ethylhydrazine; priycin;
ribostamydin; rifamide; rifampin; rifamycin SV; rifapentine;
rifaximin; ristocetin; rokitamycin; rolitetracycline; rosaramycin;
roxithromycin; sancycline; sisomicin; spectinomycin; spiramycin;
strepton; otbramycin; trospectomycin; tuberactinomycin; vancomycin;
candicidin(s); chlorphenesin; dermostatin(s); filipin;
fungichromin; meparticin; mystatin; oligomycin(s); erimycinA;
tubercidin; 6-azauridine; aclacinomycin(s); ancitabine;
anthramycin; azacitadine; bleomycin(s) carubicin; carzinophillin A;
chlorozotocin; chromomcin(s); doxifluridine; enocitabine;
epirubicin; gemcitabine; mannomustine; menogaril; atorvasi
pravastatin; clarithromycin; leuproline; paclitaxel; mitobronitol;
mitolactol; mopidamol; nogalamycin; olivomycin(s); peplomycin;
pirarubicin; prednimustine; puromycin; ranimustine; tubercidin;
vinesine; zorubicin; coumetarol; dicoumarol; ethyl biscoumacetate;
ethylidine dicoumarol; iloprost; taprostene; tioclomarol;
amiprilose; romurtide; sirolimus (rapamycin); tacrolimus; salicyl
alcohol; bromosaligenin; ditazol; fepradinol; gentisic acid;
glucamethacin; olsalazine; S-adenosylmethionine; azithromycin;
salmeterol; budesonide; albuteal; indinavir; fluvastatin;
streptozocin; doxorubicin; daunorubicin; plicamycin; idarubicin;
pentostatin; metoxantrone; cytarabine; fludarabine phosphate;
floxuridine; cladriine; capecitabien; docetaxel; etoposide;
topotecan; vinblastine; teniposide, and the like. The therapeutic
diol can be selected to be either a saturated or an unsaturated
diol.
[0068] Suitable naturally occurring and synthetic therapeutic
di-acids that can be used to prepare an amide linkage in the PEA
polymer compositions of the invention include, for example,
bambermycin(s); benazepril; carbenicillin; carzinophillin A;
cefixime; cefininox cefpimizole; cefodizime; cefonicid; ceforanide;
cefotetan; ceftazidime; ceftibuten; cephalosporin C; cilastatin;
denopterin; edatrexate; enalapril; lisinopril; methotrexate;
moxalactam; nifedipine; olsalazine; penicillin N; ramipril;
quinacillin; quinapril; temocillin; ticarcillin; Tomudex.RTM.
(N-[[5-[ [(I ,4-Dihydro-2-methyl-4-oxo-6-quinazolinyl)methyl]
methylamino]-2-thienyl]carbonyl]-L-glutamic acid), and the like.
The safety profile of naturally occurring therapeutic di-acids is
believed to surpass that of synthetic therapeutic di-acids. The
therapeutic di-acid can be either a saturated or an unsaturated
di-acid.
[0069] The chemical and therapeutic properties of the above
described therapeutic diols and di-acids as tumor inhibitors,
cytotoxic antimetabolites, antibiotics, and the like, are well
known in the art and detailed descriptions thereof can be found,
for example, in thel3th Edition of The Merck Index (Whitehouse
Station, N.J., USA).
[0070] The di-aryl sulfonic acid salts of diesters of .alpha.amino
acid and unsaturated diol can be prepared by admixing .alpha.amino
acid, e.g., p-aryl sulfonic acid monohydrate and saturated or
unsaturated diol in toluene, heating to reflux temperature, until
water evolution is minimal, then cooling. The unsaturated diols
include, for example, 2-butene-1 ,3-diol and 1,1
8-octadec-9-en-diol.
[0071] Saturated di-p-nitrophenyl esters of dicarboxylic acid and
saturated di-p-toluene sulfonic acid salts of bis-cc -amino acid
esters can be prepared as described in U.S. Pat. No. 6,503,538
B`.
[0072] Synthesis of the unsaturated poly(ester-amide)s (UPEAs)
useful as biodegradable polymers of the structural formula (I) as
disclosed above will now be described. UPEAs having the structural
formula (I) can be made in similar fashion to the compound (VII) of
U.S. Pat. No. 6,503,538 Bi, except that R.sup.4 of (III) of
6,503,538 and/or R' of (V) of 6,503,538 is (C.sub.2-C.sub.20)
alkenylene as described above. The reaction is carried out, for
example, by adding dry triethylamine to a mixture of said (III) and
(IV) of 6,503,538 and said (V) of 6,503,538 in dry
N,N-dimethylacetamide, at room temperature, then increasing the
temperature to 80.degree. C and stirring for 16 hours, then cooling
the reaction solution to room temperature, diluting with ethanol,
pouring into water, separating polymer, washing separated polymer
with water, drying to about 30.degree. C under reduced pressure and
then purifying up to negative test on p-nitrophenol and p-toluene
sulfonate. A preferred reactant (IV) of 6,503,538 is p-toluene
sulfonic acid salt of Lysine benzyl ester, the benzyl ester
protecting group is preferably removed from (II) to confer
biodegradability, but it should not be removed by hydrogenolysis as
in Example 22 of U.S. Pat. No. 6,503,538 because hydrogenolysis
would saturate the desired double bonds; rather the benzyl ester
group should be converted to an acid group by a method that would
preserve unsaturation. Alternatively, the lysine reactant (IV) of
6,503,538 can be protected by a protecting group different from
benzyl that can be readily removed in the finished product while
preserving unsaturation, e.g., the lysine reactant can be protected
with t-butyl (i.e., the reactant can be t-butyl ester of lysine)
and the t-butyl can be converted to H while preserving unsaturation
by treatment of the product (II) with acid.
[0073] A working example of the compound having structural formula
(I) is provided by substituting p-toluene sulfonic acid salt of
bis(L-phenylalanine) 2-butene-1,4-diester for (III) in Example 1 of
6,503,538 or by substituting di-p-nitrophenyl fumarate for (V) in
Example I of 6,503,538 or by substituting the p-toluene sulfonic
acid salt of bis(L-phenylalanine) 2-butene- 1,4-diester for III in
Example 1 of 6,503,538 and also substituting bis-p-nitrophenyl
fumarate for (V) in Example 1 of 6,503,538.
[0074] In unsaturated compounds having either structural formula
(I) or (IV), the following hold. An amino substituted aminoxyl
(N-oxide) radical bearing group, e.g., 4-amino TEMPO, can be
attached using carbonyldiimidazol, or suitable carbodiimide, as a
condensing agent. Bioactive agents, as described herein, can be
attached via the double bond functionality. Hydrophilicity can be
imparted by bonding to poly(ethylene glycol) diacrylate.
[0075] In yet another aspect, the PEA and PEUR polymers
contemplated for use in forming the invention polymer particle
delivery systems include those set forth in U.S. Pat. Nos. 5,516,
881; 6,476,204; 6,503,538; and in U.S. Application Nos. 10/096,435;
10/101,408; 10/143,572; and 10/194,965; the entire contents of each
of which is incorporated herein by reference.
[0076] The biodegradable PEA, PEUR and PEU polymers can contain
from one to multiple different .alpha.-amino acids per polymer
molecule and preferably have weight average molecular weights
ranging from 10,000 to 125,000; these polymers and copolymers
typically have intrinsic viscosities at 25 .degree. C., determined
by standard viscosimetric methods, ranging from 0.3 to 4.0, for
example, ranging from 0.5 to 3.5.
[0077] PEA and PEUR polymers contemplated for use in the practice
of the invention can be synthesized by a variety of methods well
known in the art. For example, tributyltin (IV) catalysts are
commonly used to form polyesters such as poly(F-caprolactone),
poly(glycolide), poly(lactide), and the like. However, it is
understood that a wide variety of catalysts can be used to form
polymers suitable for use in the practice of the invention.
[0078] Such poly(caprolactones) contemplated for use have an
exemplary structural formula (X) as follows: ##STR22##
[0079] Poly(glycolides) contemplated for use have an exemplary
structural formula (XI) as follows: ##STR23##
[0080] Poly(lactides) contemplated for use have an exemplary
structural formula (XII) as follows: ##STR24##
[0081] An exemplary synthesis of a suitable
poly(lactide-co-&-caprolactone) including an aminoxyl moiety is
set forth as follows. The first step involves the copolymerization
of lactide and .epsilon.-caprolactone in the presence of benzyl
alcohol using stannous octoate as the catalyst to form a polymer of
structural formula (XIV). ##STR25##
[0082] The hydroxy terminated polymer chains can then be capped
with maleic anhydride to form polymer chains having structural
formula (XVI): ##STR26##
[0083] At this point, 4-amino-2,2,6,6-tetramethylpiperidine-1-oxy
can be reacted with the carboxylic end group to covalently attach
the aminoxyl moiety to the copolymer via the amide bond which
results from the reaction between the 4-amino group and the
carboxylic acid end group. Alternatively, the maleic acid capped
copolymer can be grafted with polyacrylic acid to provide
additional carboxylic acid moieties for subsequent attachment of
further aminoxyl groups.
[0084] In unsaturated compounds having structural formula (VII) for
PEU the following hold: An amino substituted aminoxyl (N-oxide)
radical bearing group e.g., 4-amino TEMPO, can be attached using
carbonyldiimidazole, or suitable carbodiimide, as a condensing
agent. Additional bioactive agents, and the like, as described
herein, optionally can be attached via the double bond
functionality provided that the therapeutic diol residue in the
polymer composition does not contain a double or triple bond.
[0085] For example, the invention high molecular weight
semi-crystalline PEUs having structural formula (VI) can be
prepared inter-facially by using phosgene as a bis-electrophilic
monomer in a chloroform/water system, as shown in the reaction
scheme (II) below: ##STR27## Synthesis of copoly(ester ureas)
(PEUs) containing L-Lysine esters and having structural formula
(VII) can be carried out by a similar scheme (III): ##STR28## A 20%
solution of phosgene (C.sub.1CO.sub.1) (highly toxic) in toluene,
for example (commercially available (Fluka Chemie, GMBH, Buchs,
Switzerland), can be substituted either by diphosgene
(trichloromethylchloroformate) or triphosgene
(bis(trichloromethyl)carbonate). Less toxic carbonyldiimidazole can
be also used as a bis-electrophilic monomer instead of phosgene,
di-phosgene, or tri-phosgene.
General Procedure for Synthesis of PEUs
[0086] It is necessary to use cooled solutions of monomers to
obtain PEUs of high molecular weight. For example, to a suspension
of di-p-toluenesulfonic acid salt of bis(a-amino acid)-a,o-
alkylene diester in 150 mL of water, anhydrous sodium carbonate is
added, stirred at room temperature for about 30 minutes and cooled
to about 2 - 0 .degree. C., forming a first solution. In parallel,
a second solution of phosgene in chloroform is cooled to about 15
-10 .degree. C. The first solution is placed into a reactor for
interfacial polycondensation and the second solution is quickly
added at once and stirred briskly for about 15 min. Then chloroform
layer can be separated, dried over anhydrous Na.sub.2SO.sub.4, and
filtered. The obtained solution can be stored for further use.
[0087] All the exemplary PEU polymers fabricated were obtained as
solutions in chloroform and these solutions are stable during
storage. However, some polymers, for example, 1 -Phe-4, become
insoluble in chloroform after separation. To overcome this problem,
polymers can be separated from chloroform solution by casting onto
a smooth hydrophobic surface and allowing chloroform to evaporate
to dryness. No further purification of obtained PEUs is needed. The
yield and characteristics of exemplary PEUs obtained by this
procedure are summarized in Table 1 herein.
General Procedure for Preparation of porous PEUs.
[0088] Methods for making the PEU polymers containing .alpha.-amino
acids in the general formula will now be described. For example,
for the embodiment of the polymer of formula (I) or (II), the
.alpha.-amino acid can be converted into a bis(.alpha.-amino
acid)-.alpha.,.omega.-diol-diester monomer, for example, by
condensing the .alpha.-amino acid with a diol HO-R.sub.1-OH. As a
result, ester bonds are formed. Then, acid chloride of carbonic
acid (phosgene, diphosgene, triphosgene) is entered into a
polycondensation reaction with a di-p-toluenesulfonic acid salt of
a bis(a-amino acid)-alkylene diester to obtain the final polymer
having both ester and urea bonds. In the present invention, at
least one therapeutic diol can be used in the polycondensation
protocol.
[0089] The unsaturated PEUs can be prepared by interfacial solution
condensation of di-p-toluenesulfonate salts of bis(.alpha.-amino
acid)-alkylene diesters, comprising at least one double bond in
R.sup.1. Unsaturated diols useful for this purpose include, for
example, 2-butene-1,4-diol and 1,18-octadec-9-en-diol. Unsaturated
monomer can be dissolved prior to the reaction in alkaline water
solution, e.g. sodium hydroxide solution. The water solution can
then be agitated intensely, under external cooling, with an organic
solvent layer, for example chloroform, which contains an equimolar
amount of monomeric, dimeric or trimeric phosgene. An exothermic
reaction proceeds rapidly, and yields a polymer that (in most
cases) remains dissolved in the organic solvent. The organic layer
can be washed several times with water, dried with anhydrous sodium
sulfate, filtered, and evaporated. Unsaturated PEUs with a yield of
about 75%-85% can be dried in vacuum, for example at about
45.degree. C.
[0090] To obtain a porous, strong material, L-Leu based PEUs, such
as 1-L-Leu-4 and 1-L-Leu-6, can be fabricated using the general
procedure described below. Such procedure is less successful in
formation of a porous, strong material when applied to L-Phe based
PEUs.
[0091] The reaction solution or emulsion (about 100 mL) of PEU in
chloroform, as obtained just after interfacial polycondensation, is
added dropwise with stirring to 1,000 mL of about 80 .degree. C.
-85 .degree. C. water in a glass beaker, preferably a beaker made
hydrophobic with dimethyldichlorsilane to reduce the adhesion of
PEU to the beaker's walls. The polymer solution is broken in water
into small drops and chloroform evaporates rather vigorously.
Gradually, as chloroform is evaporated, small drops combine into a
compact tar-like mass that is transformed into a sticky rubbery
product. This rubbery product is removed from the beaker and put
into hydrophobized cylindrical glass-test-tube, which is
thermostatically controlled at about 80 .degree. C. for about 24
hours. Then the test-tube is removed from the thermostat, cooled to
room temperature, and broken to obtain the polymer. The obtained
porous bar is placed into a vacuum drier and dried under reduced
pressure at about 80 .degree. C. for about 24 hours. In addition,
any procedure known in the art for obtaining porous polymeric
materials can also be used.
[0092] Properties of high-molecular-weight porous PEUs made by the
above procedure yielded results as summarized in Table 2.
TABLE-US-00001 TABLE 1 Properties of PEU Polymers of Formula (VI)
and (VII). Yield .eta..sub.red.sup.a) Tg.sup.c) T.sub.m.sup.c) PEU*
[%] [dL/g] M.sub.w.sup.b) M.sub.n.sup.b) M.sub.w/M.sub.n.sup.b)
[.degree. C.] [.degree. C.] 1-L-Leu-4 80 0.49 84000 45000 1.90 67
103 1-L-Leu-6 82 0.59 96700 50000 1.90 64 126 1-L-Phe-6 77 0.43
60400 34500 1.75 -- 167 [1-L-Leu-6].sub.0.75- [1-L- 84 0.31 64400
43000 1.47 34 114 Lys(OBn)].sub.0.25 1-L-Leu-DAS 57 0.28
55700.sup.d) 27700.sup.d) 2.1.sup.d) 56 165 *PEUs of general
formula (VI), where, 1-L-Leu-4: R.sup.4 = (CH.sub.2).sub.4, R.sup.3
= i-C.sub.4H.sub.9 1-L-Leu-6: R.sup.4 = (CH.sub.2).sub.6, R.sup.3 =
i-C.sub.4H.sub.9 1-L-Phe-6:. R.sup.4 = (CH.sub.2).sub.6, R.sup.3 =
--CH.sub.2--C.sub.6H.sub.5. 1-L-Leu-DAS: R.sup.4 =
1,4:3,6-dianhydrosorbitol, R.sup.3 = i-C.sub.4H .sup.a)Reduced
viscosities were measured in DMF at 25.degree. C. and a
concentration 0.5 g/dL .sup.b)GPC Measurements were carried out in
DMF, (PMMA) .sup.c)Tg taken from second heating curve from DSC
Measurements (heating rate 10.degree. C./min). .sup.d)GPC
Measurements were carried out in DMAc, (PS)
[0093] Tensile strength of illustrative synthesized PEUs was
measured and results are summarized in Table 2. Tensile strength
measurement was obtained using dumbbell-shaped PEU films
(4.times.1.6 cm), which were cast from chloroform solution with
average thickness of 0.125 mm and subjected to tensile testing on
tensile strength machine (Chatillon TDC200) integrated with a PC
using Nexygen FM software (Amtek, Largo, FL) at a crosshead speed
of 60 mm/min. Examples illustrated herein can be expected to have
the following mechanical properties:
[0094] 1. A glass transition temperature in the range from about 30
C.degree. to about 90 C.degree., for example, in the range from
about 35 C.degree. to about 70 C.degree.;
[0095] 2. A film of the polymer with average thickness of about 1.6
cm will have tensile stress at yield of about 20 Mpa to about 150
Mpa, for example, about 25 Mpa to about 60 Mpa;
[0096] 3. A film of the polymer with average thickness of about 1.6
cm will have a percent elongation of about 10% to about 200%, for
example about 50% to about 150%; and
[0097] 4. A film of the polymer with average thickness of about 1.6
cm will have a Young's modulus in the range from about 500 MPa to
about 2000 MPa. Table 2 below summarizes the properties of
exemplary PEUs of this type. TABLE-US-00002 TABLE 2 Mechanical
Properties of PEUs Tensile Stress Percent Young's Tg.sup.a) at
Yield Elongation Modulus Polymer designation (.degree. C.) (MPa)
(%) (MPa) 1-L-Leu-6 64 21 114 622 [1-L-Leu-6].sub.0.75-[1-L- 34 25
159 915 Lys(OBn)].sub.0.25
[0098] Polymers usefuil in the invention polymer particle delivery
compositions, such as PEA, PEUR and PEU polymers, biodegrade by
enzymatic action at the surface. Therefore, the polymers, for
example particles thereof, administer the bioactive agent to the
subject at a controlled release rate, which is specific and
constant over a prolonged period. Additionally, since PEA, PEUR and
PEU polymers break down in vivo via hydrolytic enzymes without
production of adverse side products, the invention polymer particle
delivery compositions are substantially non-inflammatory.
[0099] As used herein "dispersed" means at least one bioactive
agent as disclosed herein is dispersed, mixed, dissolved,
homogenized, and/or covalently bound ("dispersed") in a polymer
particle, for example attached to the surface of the particle.
[0100] While the bioactive agents can be dispersed within the
polymer matrix without chemical linkage to the polymer carrier, it
is also contemplated that the bioactive agent or covering molecule
can be covalently bound to the biodegradable polymers via a wide
variety of suitable functional groups. For example, when the
biodegradable polymer is a polyester, the carboxyl group chain end
can be used to react with a complimentary moiety on the bioactive
agent or covering molecule, such as hydroxy, amino, thio, and the
like. A wide variety of suitable reagents and reaction conditions
are disclosed, e.g., in March's Advanced Organic Chemistry,
Reactions, Mechanisms, and Structure, Fifth Edition, (2001); and
Comprehensive Organic Transformations, Second Edition, Larock
(1999).
[0101] In other embodiments, a bioactive agent can be linked to the
PEA, PEUR or PEU polymers described herein through an amide, ester,
ether, amino, ketone, thioether, sulfinyl, sulfonyl, disulfide
linkage. Such a linkage can be formed from suitably functionalized
starting materials using synthetic procedures that are known in the
art.
[0102] For example, in one embodiment a polymer can be linked to
the bioactive agent via an end or pendent carboxyl group (e.g.,
COOH) of the polymer. For example, a compound of structures III,
V,and VII can react with an amino functional group or a hydroxyl
functional group of a bioactive agent to provide a biodegradable
polymer having the bioactive agent attached via an amide linkage or
carboxylic ester linkage, respectively. In another embodiment, the
carboxyl group of the polymer can be benzylated or transformed into
an acyl halide, acyl anhydride/"mixed" anhydride, or active ester.
In other embodiments, the free -NH.sub.2 ends of the polymer
molecule can be acylated to assure that the bioactive agent will
attach only via a carboxyl group of the polymer and not to the free
ends of the polymer.
[0103] Water soluble covering molecule(s), such as poly(ethylene
glycol) (PEG); phosphoryl choline (PC); glycosaminoglycans
including heparin; polysaccharides including polysialic acid;
poly(ionizable or polar amino acids) including polyserine,
polyglutamic acid, polyaspartic acid, polylysine and polyarginine;
chitosan and alginate, as described herein, and targeting
molecules, such as antibodies, antigens and ligands, can also be
conjugated to the polymer in the exterior of the particles after
production of the particles to block active sites not occupied by
the bioactive agent or to target delivery of the particles to a
specific body site as is known in the art. The molecular weights of
PEG molecules on a single particle can be substantially any
molecular weight in the range from about 200 to about 200,000, so
that the molecular weights of the various PEG molecules attached to
the particle can be varied.
[0104] Alternatively, the bioactive agent or covering molecule can
be attached to the polymer via a linker molecule, for example, as
described in structural formulas (VIII-XI). Indeed, to improve
surface hydrophobicity of the biodegradable polymer, to improve
accessibility of the biodegradable polymer towards enzyme
activation, and to improve the release profile of the biodegradable
polymer, a linker may be utilized to indirectly attach the
bioactive agent to the biodegradable polymer. In certain
embodiments, the linker compounds include poly(ethylene glycol)
having a molecular weight (MW) of about 44 to about 10,000,
preferably 44 to 2000; amino acids, such as serine; polypeptides
with repeat number from I to 100; and any other suitable low
molecular weight polymers. The linker typically separates the
bioactive agent from the polymer by about 5 angstroms up to about
200 angstroms.
[0105] In still further embodiments, the linker is a divalent
radical of formula W-A-Q, wherein A is (C.sub.1-C.sub.24) alkyl,
(C.sub.2-C.sub.24) alkenyl, (C.sub.2-C.sub.24) alkynyl,
(C.sub.3-C.sub.8) cycloalkyl, or (C.sub.6-C.sub.10) aryl, and W and
Q are each independently -N(R)C(=O)-, -C(=O)N(R)-, -OC(=O)-,
-C(=O)O,-O-, -S-, -S(O), -S(O).sub.2-, -S-S-, -N(R)-, -C(=O)-,
wherein each R is independently H or (C.sub.1-C.sub.6) alkyl.
[0106] As used to describe the above linkers, the term "alkyl"
refers to a straight or branched chain hydrocarbon group including
methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl,
n-hexyl, and the like.
[0107] As used herein, "alkenyl" refers to straight or branched
chain hydrocarbyl groups having one or more carbon-carbon double
bonds.
[0108] As used herein, "alkynyl" refers to straight or branched
chain hydrocarbyl groups having at least one carbon-carbon triple
bond.
[0109] As used herein, "aryl" refers to aromatic groups having in
the range of 6 up to 14 carbon atoms.
[0110] In certain embodiments, the linker may be a polypeptide
having from about 2 up to about 25 amino acids. Suitable peptides
contemplated for use include poly-L-glycine, poly-L-lysine,
poly-L-glutamic acid, poly-L-aspartic acid, poly-L-histidine,
poly-L-omithine, poly-L-serine, poly-L-threonine, poly-L-tyrosine,
poly-L-leucine, poly-L-lysine-L-phenylalanine, poly-L-arginine,
poly-L-lysine-L-tyrosine, and the like.
[0111] In one embodiment, the bioactive agent can covalently
crosslink the polymer, i.e. the bioactive agent is bound to more
than one polymer molecule. This covalent crosslinking can be done
with or without additional polymer-bioactive agent linker.
[0112] The bioactive agent molecule can also be incorporated into
an intramolecular bridge by covalent attachment between two polymer
molecules.
[0113] A linear polymer polypeptide conjugate is made by protecting
the potential nucleophiles on the polypeptide backbone and leaving
only one reactive group to be bound to the polymer or polymer
linker construct. Deprotection is performed according to methods
well known in the art for deprotection of peptides (Boc and Fmoc
chemistry for example).
[0114] In one embodiment of the present invention, a polypeptide
bioactive agent is presented as retro-inverso or partial
retro-inverso peptide.
[0115] In other embodiments the bioactive agent is mixed with a
photocrosslinkable version of the polymer in a matrix, and after
crosslinking the material is dispersed (ground) to an average
diameter in the range from about 0.1 to about 10 .mu.m.
[0116] The linker can be attached first to the polymer or to the
bioactive agent or covering molecule. During synthesis, the linker
can be either in unprotected form or protected form, using a
variety of protecting groups well known to those skilled in the
art. In the case of a protected linker, the unprotected end of the
linker can first be attached to the polymer or the bioactive agent
or covering molecule. The protecting group can then be de-protected
using Pd/H.sub.2 hydrogenolysis, mild acid or base hydrolysis, or
any other common de-protection method that is known in the art. The
de-protected linker can then be attached to the bioactive agent or
covering molecule, or to the polymer
[0117] An exemplary synthesis of a biodegradable polymer according
to the invention (wherein the molecule to be attached is an
aminoxyl) is set forth as follows.
[0118] A polyester can be reacted with an amino-substituted
aminoxyl (N-oxide) radical bearing group, e.g.,
4-amino-2,2,6,6-tetramethylpiperidine-1-oxy, in the presence of
N,N'-carbonyldiimidazole to replace the hydroxyl moiety in the
carboxyl group at the chain end of the polyester with an
amino-substituted aminoxyl-(N-oxide) radical bearing group, so that
the amino moiety covalently bonds to the carbon of the carbonyl
residue of the carboxyl group to form an amide bond. The
N,N'-carbonyl diimidazole or suitable carbodiimide converts the
hydroxyl moiety in the carboxyl group at the chain end of the
polyester into an intermediate product moiety which will react with
the aminoxyl, e.g., 4-amino-2,2,6,6-tetramethylpiperidine-I-oxy.
The aminoxyl reactant is typically used in a mole ratio of reactant
to polyester ranging from 1 :1 to 100:1. The mole ratio of
N,N'-carbonyl diimidazole to aminoxyl is preferably about 1:1.
[0119] A typical reaction is as follows. A polyester is dissolved
in a reaction solvent and reaction is readily carried out at the
temperature utilized for the dissolving. The reaction solvent may
be any in which the polyester will dissolve. When the polyester is
a polyglycolic acid or a poly(glycolide-L-lactide) (having a
monomer mole ratio of glycolic acid to L-lactic acid greater than
50:50), highly refined (99.9+% pure) dimethyl sulfoxide at 115
.degree. C. to 130 .degree. C. or DMSO at room temperature suitably
dissolves the polyester. When the polyester is a poly-L-lactic
acid, a poly-DL-lactic acid or a poly(glycolide-L-lactide) (having
a monomer mole ratio of glycolic acid to L-lactic acid 50:50 or
less than 50:50), tetrahydrofuran, dichloromethane (DCM) and
chloroform at room temperature to 40 .about.50 .degree. C. suitably
dissolve the polyester.
Polymer-Bioactive agent Linkage
[0120] In one embodiment, the polymers used to make the invention
polymer particle delivery compositions as described herein have one
or more bioactive agent directly linked to the polymer. The
residues of the polymer can be linked to the residues of the one or
more bioactive agents. For example, one residue of the polymer can
be directly linked to one residue of the bioactive agent. The
polymer and the bioactive agent can each have one open valence.
Alternatively, more than one bioactive agent, multiple bioactive
agents, or a mixture of bioactive agents having different
therapeutic or palliative activity can be directly linked to the
polymer. However, since the residue of each bioactive agent can be
linked to a corresponding residue of the polymer, the number of
residues of the one or more bioactive agents can correspond to the
number of open valences on the residue of the polymer.
[0121] As used herein, a "residue of a polymer" refers to a radical
of a polymer having one or more open valences. Any synthetically
feasible atom, atoms, or functional group of the polymer (e.g., on
the polymer backbone or pendant group) of the present invention can
be removed to provide the open valence, provided bioactivity is
substantially retained when the radical is attached to a residue of
a bioactive agent. Additionally, any synthetically feasible
functional group (e.g., carboxyl) can be created on the polymer
(e.g., on the polymer backbone or pendant group) to provide the
open valence, provided bioactivity is substantially retained when
the radical is.attached to a residue of a bioactive agent. Based on
the linkage that is desired, those skilled in the art can select
suitably functionalized starting materials that can be derived from
the polymer of the present invention using procedures that are
known in the art.
[0122] As used herein, a "residue of a compound of structural
formula (*)" refers to a radical of a compound of polymer formulas
(I) and (III-VII) as described herein having one or more open
valences. Any synthetically feasible atom, atoms, or functional
group of the compound (e.g., on the polymer backbone or pendant
group) can be removed to provide the open valence, provided
bioactivity is substantially retained when the radical is attached
to a residue of a bioactive agent. Additionally, any synthetically
feasible functional group (e.g., carboxyl) can be created on the
compound of formulas (1) and (III-VII) (e.g., on the polymer
backbone or pendant group) to provide the open valance, provided
bioactivity is substantially retained when the radical is attached
to a residue of a bioactive agent. Based on the linkage that is
desired, those skilled in the art can select suitably
functionalized starting materials that can be derived from the
compound of formulas (I) and III-VII) using procedures that are
known in the art.
[0123] For example, the residue of a bioactive agent can be linked
to the residue of a compound of structural formula (I) or (III)
through an amide (e.g., -N(R)C(=O)-or --C(=O)N(R)-), ester
(e.g.,-OC(=O)-or--C(=O)O-), ether (e.g.,-O-), amino (e.g.,-N(R)-),
ketone (e.g., -C(=O)-), thioether (e.g.,-S-), sulfinyl
(e.g.,-S(O)-), sulfonyl (e.g., -S(O).sub.2-), disulfide
(e.g.,-S-S-), or a direct (e.g., C-C bond) linkage, wherein each R
is independently H or (C.sub.1-C.sub.6) alkyl. Such a linkage can
be formed from suitably functionalized starting materials using
synthetic procedures that are known in the art. Based on the
linkage that is desired, those skilled in the art can select
suitably functional starting material that can be derived from a
residue of a compound of structural formula (I) or (III) and from a
given residue of a bioactive agent or adjuvant using procedures
that are known in the art. The residue of the bioactive agent or
adjuvant can be linked to any synthetically feasible position on
the residue of a compound of structural formula (I) or (III).
Additionally, the invention also provides compounds having more
than one residue of a bioactive agent or adjuvant bioactive agent
directly linked to a compound of structural formula (I) or
(III).
[0124] The number of bioactive agents that can be linked to the
polymer molecule can typically depend upon the molecular weight of
the polymer. For example, for a compound of structural formula (I),
wherein n is about 5 to about 150, preferably about 5 to about 70,
up to about 150 bioactive agent molecules (i.e., residues thereof)
can be directly linked to the polymer (i.e., residue thereof) by
reacting the bioactive agent with side groups of the polymer. In
unsaturated polymers, the bioactive agents can also be reacted with
double (or triple) bonds in the polymer.
[0125] The number of bioactive agents that can be linked to the
polymer molecule can typically depend upon the molecular weight of
the polymer. For example, for a saturated compound of structural
formula (I), wherein n is about 5 to about 150, preferably about 5
to about 70, up to about 150 bioactive agents (i.e., residues
thereof) can be directly linked to the polymer (i.e., residue
thereof) by reacting the bioactive agent with side groups of the
polymer. In unsaturated polymers, the bioactive agents can also be
reacted with double (or triple) bonds in the polymer.
[0126] PEA, PEUR and PEU polymers described herein absorb water, (5
to 25 % w/w water up-take, on polymer film) allowing hydrophilic
molecules to readily diffuse therethrough. This characteristic
makes these polymers suitable for use as an over coating on
particles to control release rate. Water absorption also enhances
biocompatibility of the polymers and the polymer particle delivery
composition based on such polymers. In addition, due to the
hydrophilic properties of the PEA, PEUR and PEU polymers, when
delivered in vivo the particles become sticky and agglomerate,
particularly at in vivo temperatures. Thus the polymer particles
spontaneously form polymer depots when injected subcutaneously or
intramuscularly for local delivery, such as by subcutaneous needle
or needle-less injection. Particles with average diameter range
from about I micron to about 100 microns, which size will not
circulate efficiently within the body, are suitable for forming
such polymer depots in vivo. Alternatively, for oral administration
the GI tract can tolerate much larger particles, for example micro
particles of about I micron up to about 1000 microns average
diameter.
[0127] Particles suitable for use in the invention polymer particle
delivery compositions can be made using immiscible solvent
techniques. Generally, these methods entail the preparation of an
emulsion of two immiscible liquids. A single emulsion method can be
used to make polymer particles that incorporate at least one
hydrophobic bioactive agent. In the single emulsion method,
bioactive agents to be incorporated into the particles are mixed
with polymer in solvent first, and then emulsified in water
solution with a surface stabilizer, such as a surfactant. In this
way, polymer particles with hydrophobic bioactive agent conjugates
are formed and suspended in the water solution, in which
hydrophobic conjugates in the particles will be stable without
significant elution into the aqueous solution, but such molecules
will elute into body tissue, such as muscle tissue.
[0128] Most biologics, including polypeptides, proteins, DNA, cells
and the like, are hydrophilic. A double emulsion method can be used
to make polymer particles with interior aqueous phase and
hydrophilic bioactive agents dispersed within. In the double
emulsion method, aqueous phase or hydrophilic bioactive agents
dissolved in water are emulsified in polymer lipophilic solution
first to form a primary emulsion, and then the primary emulsion is
put into water to emulsify again to form a second emulsion, in
which particles are formed having a continuous polymer phase and
aqueous bioactive agent(s) in the dispersed phase. Surfactant and
additive can be used in both emulsifications to prevent particle
aggregation. Chloroform or DCM, which are not miscible in water,
are used as solvents for PEA and PEUR polymers, but later in the
preparation the solvent is removed, using methods known in the
art.
[0129] For certain bioactive agents with low water solubility,
however, these two emulsion methods have limitations. In this
context, "low water solubility" means a bioactive agent that is
less hydrophobic than truly lipophilic drugs, such as Taxol, but
which are less hydrophilic than truly water-soluble drugs, such as
many biologics. These types of intermediate compounds are too
hydrophilic for high loading and stable matrixing into single
emulsion particles, yet are too hydrophobic for high loading and
stability within double emulsions. In such cases, a polymer layer
is coated onto particles made of polymer and drugs with low water
solubility, by a triple emulsion process, as illustrated
schematically in FIG. 7. This method provides relatively low drug
loading (.about.10% w/w), but provides structure stability and
controlled drug release rate.
[0130] In the triple emulsion process, the first emulsion is made
by mixing the bioactive agents into polymer solution and then
emulsifying the mixture in aqueous solution with surfactant or
lipid, such as di-(hexadecanoyl)phosphatidylcholine (DHPC; a
short-chain derivative of a natural lipid). In this way, particles
containing the active agents are formed and suspended in water to
form the first emulsion. The second emulsion is formed by putting
the first emulsion into a polymer solution, and emulsifying the
mixture, so that water drops with the polymer/drug particles inside
are formed within the polymer solution. Water and surfactant or
lipid will separate the particles and dissolve the particles in the
polymer solution. The third emulsion is then formed by putting the
second emulsion into water with surfactant or lipid, and
emulsifying the mixture to form the final particles in water. The
resulting particle structure, as illustrated in FIG. 7, will have
one or more particles made with polymer plus bioactive agent at the
center, surrounded by water and surface stabilizer, such as
surfactant or lipid, and covered with a pure polymer shell. Surface
stabilizer and water will prevent solvent in the polymer coating
from contacting the particles inside the coating and dissolving
them.
[0131] To increase loading of bioactive agents by the triple
emulsion method, active agents with low water solubility can be
coated with surface stabilizer in the first emulsion, without
polymer coating-and without dissolving the bioactive agent in
water. In this first emulsion, water, surface stabilizer and active
agent have similar volume or in the volume ratio range of (1 to
3):(0.2 to about 2):1, respectively. In this case, water is used,
not for dissolving the active agent, but rather for protecting the
bioactive agent with help of surface stabilizer. Then the double
and triple emulsions are prepared as described above. This method
can provide up to 50% drug loading.
[0132] Alternatively or additionally in the single, double or
triple emulsion methods described above, a bioactive agent can be
conjugated to the polymer molecule as described herein prior to
using the polymers to make the particles. Alternatively still, a
bioactive agent can be conjugated to the polymer on the exterior of
the particles described herein after production of the
particles.
[0133] Many emulsification techniques will work in making the
emulsions described above. However, the presently preferred method
of making the emulsion is by using a solvent that is not miscible
in water. For example, in the single emulsion method, the
emulsifying procedure consists of dissolving polymer with the
solvent, mixing with bioactive agent molecule(s), putting into
water, and then stirring with a mixer and/or ultra-sonicator.
Particle size can be controlled by controlling stir speed and/or
the concentration of polymer, bioactive agent(s), and surface
stabilizer. Coating thickness can be controlled by adjusting the
ratio of the second to the third emulsion.
[0134] Suitable emulsion stabilizers may include nonionic surface
active agents, such as mannide monooleate, dextran 70,000,
polyoxyethylene ethers, polyglycol ethers, and the like, all
readily commercially available from, e.g., Sigma Chemical Co., St.
Louis, Mo. The surface active agent will be present at a
concentration of about 0.3% to about 10%, preferably about 0.5% to
about 8%, and more preferably about 1% to about 5%.
[0135] Rate of release of the at least one bioactive agent from the
invention compositions can be controlled by adjusting the coating
thickness, particle size, structure, and density of the coating.
Density of the coating can be adjusted by adjusting loading of the
bioactive agent conjugated to the coating. For example, when the
coating contains no bioactive agent, the polymer coating is
densest, and a bioactive agent from the interior of the particle
elutes through the coating most slowly. By contrast, when a
bioactive agent is loaded into (i.e. is mixed or "matrixed" with),
or alternatively is conjugated to, polymer in the coating, the
coating becomes porous once the bioactive agent has become free of
polymer and has eluted out, starting from the outer surface of the
coating. Thereby, a bioactive agent at the center of the particle
can elute at an increased rate. The higher the bioactive agent
loading in the coating, the lower the density of the coating layer
and the higher the elution rate. The loading of bioactive agent in
the coating can be lower or higher than that in the interior of the
particles beneath the exterior coating. Release rate of bioactive
agent(s) from the particles can also be controlled by mixing
particles with different release rates prepared as described
above.
[0136] A detailed description of methods of making double and
triple emulsion polymers may be found in Pierre Autant et al,
Medicinal and/or nutritional microcapsules for oral administration,
U.S. Pat. No. 6,022,562; losif Daniel Rosca et al., Microparticle
formation and its mechanism in single and double emulsion solvent
evaporation, Journal of Controlled Release 99 (2004) 271-280; L.
Mu, S.S. Feng, A novel controlled release formulation for the
anticancer drug paclitaxel (Taxol): PLGA nanoparticles containing
vitamin E TPGS, J Control. Release 86 (2003) 33- 48; Somatosin
containing biodegradable microspheres prepared by a modified
solvent evaporation method based on W/O/W-multiple emulsions, Int.
J Pharm. 126 (1995) 129- 138 and F. Gabor, B. Ertl, M. Wirth, R.
Mallinger, Ketoprofenpoly(d,l-lactic-co-glycolic acid)
microspheres: influence of manufacturing parameters and type of
polymer on the release characteristics, J Microencapsul. 16 (1)
(1999) 1- 12, each of which is incorporated herein in its
entirety.
[0137] In yet further embodiments for delivery of aqueous-soluble
bioactive agents, the particles can be made into nanoparticles
having an average diameter of about 20 nm to about 200 nm for
delivery to the circulation. The nanoparticles can be made by the
single emulsion method with the active agent dispersed therein,
i.e., mixed into the emulsion or conjugated to polymer as described
herein. The nanoparticles can also be provided as a micellar
composition containing the polymers described herein, such as PEA
and PEUR with the bioactive agents conjugated thereto.
Alternatively or in addition to bioactive agents conjugated to the
polymers, since the micelles are formed in water, water soluble
bioactive agents can be loaded into the micelles at the same time
without solvent.
[0138] More particularly, the biodegradable micelles, which are
illustrated in FIG. 10, are formed of a hydrophobic polymer chain
conjugated to a water soluble polymer chain. Whereas, the outer
portion of the micelle mainly consists of the water soluble ionized
or polar section of the polymer, the hydrophobic section of the
polymer mainly partitions to the interior of the micelles and holds
the polymer molecules together.
[0139] The biodegradable hydrophobic section of the polymer used to
make micelles is made of PEA, PEUR or PEU polymers, as described
herein. For strongly hydrophobic PEA, PEUR or PEU polymers,
components such as di- L-leucine ester of
1,4:3,6-dianhydro-D-sorbitol or rigid aromatic di-acid like
a,o)-bis (4-carboxyphenoxy) (C.sub.1-C.sub.8) alkane may be
included in the polymer repeat unit. By contrast, the water soluble
section of the polymer comprises repeating alternating units of
polyethylene glycol, polyglycosaminoglycan or polysaccharide and at
least one ionizable or polar amino acid, wherein the repeating
alternating units have substantially similar molecular weights and
wherein the molecular weight of the polymer is in the range from
about 10 kD to about 300 kD. The repeating alternating units may
have substantially similar molecular weights in the range from
about 300D to about 700D. In one embodiment wherein the molecular
weight of the polymer is over 10 kD, at least one of the amino acid
units is an ionizable or polar amino acid selected from serine,
glutamic acid, aspartic acid, lysine and arginine. In one
embodiment, the units of ionizable amino acids comprise at least
one block of ionizable poly(amino acids), such as glutamate or
aspartate, can be included in the polymer. The invention micellar
composition may further comprise a pharmaceutically acceptable
aqueous media with a pH value at which at least a portion of the
ionizable amino acids in the water soluble sections of the polymer
are ionized.
[0140] The higher the molecular weight of the water soluble section
of the polymer, the greater the porosity of the micelle and the
higher the loading into the micelles of water soluble bioactive
agents and/or large bioactive agents, such as proteins. In one
embodiment, therefore, the molecular weight of the complete water
soluble section of the polymer is in the range from about 5 kD to
about 100 kD.
[0141] Once formed, the micelles can be lyophilized for storage and
shipping and reconstituted in the above-described aqueous media.
However, it is not recommended to lyophilize micelles containing
certain bioactive agents, such as certain proteins, that would be
denatured by the lyophilization process.
[0142] Charged moieties within the micelles partially separate from
each other in water, and create space for absorption of water
soluble agents, such as the bioactive agent(s). Ionized chains with
the same type of charge will repel each other and create more
space. The ionized polymer also attracts the bioactive agent,
providing stability to the matrix. In addition, the water soluble
exterior of the micelle prevents adhesion of the micelles to
proteins in body fluids after ionized sites are taken by the
therapeutic bioactive agent. This type of micelle has very high
porosity, up to 95% of the micelle volume, allowing for high
loading of aqueous-soluble biologics, such as polypeptides, DNA,
and other bioactive agents. Particle size range of the micelles is
about 20 nm to about 200nm, with about 20 nm to about 100 nm being
preferred for circulation in the blood.
[0143] Particle size can be determined by, e.g., laser light
scattering, using for example, a spectrometer incorporating a
helium-neon laser. Generally, particle size is determined at room
temperature and involves multiple analyses of the sample in
question (e.g., 5-10 times) to yield an average value for the
particle diameter. Particle size is also readily determined using
scanning electron microscopy (SEM). In order to do so, dry
particles are sputter-coated with a gold/palladium mixture to a
thickness of approximately 100 Angstroms, and then examined using a
scanning electron microscope. Alternatively, the polymer, either in
the form of particles or not, can be covalently attached directly
to the bioactive agent, rather than incorporating active agent
therein (''loading) without chemical attachment, using any of
several methods well known in the art and as described hereinbelow.
The bioactive agent content is generally in an amount that
represents approximately 0. 1% to about 40% (w/w) bioactive agent
to polymer, more preferably about 1% to about 25% (w/w) bioactive
agent, and even more preferably about 2% to about 20% (w/w)
bioactive agent. The percentage of bioactive agent will depend on
the desired dose and the condition being treated, as discussed in
more detail below.
[0144] Bioactive agents for dispersion into and release from the
invention biodegradable polymer particle delivery compositions also
include anti-proliferants, rapamycin and any of its analogs or
derivatives, paclitaxel or any of its taxene analogs or
derivatives, everolimus, Sirolimus, tacrolimus, or any of its-limus
named family of drugs, and statins such as simvastatin,
atorvastatin, fluvastatin, pravastatin, lovastatin, rosuvastatin,
geldanamycins, such as 17 AAG
(17-allylamino-17-demethoxygeldanamycin); Epothilone D and other
epothilones, 17-dimethylaminoethylamino-17-demethoxy-geldanamycin
and other polyketide inhibitors of heat shock protein 90 (Hsp90),
Cilostazol, and the like.
[0145] Additional bioactive agents contemplated for dispersion
within the polymers used in the invention polymer particle delivery
compositions include agents that, when freed or eluted from the
polymer particles during their degradation, promote endogenous
production of a therapeutic natural wound healing agent, such as
nitric oxide, which is endogenously produced by endothelial cells.
Alternatively the bioactive agents released from the polymers
during degradation may be directly active in promoting natural
wound healing processes by endothelial cells. These bioactive
agents can be any agent that donates, transfers, or releases nitric
oxide, elevates endogenous levels of nitric oxide, stimulates
endogenous synthesis of nitric oxide, or serves as a substrate for
nitric oxide synthase or that inhibits proliferation of smooth
muscle cells. Such agents include, for example, aminoxyls,
furoxans, nitrosothiols, nitrates and anthocyanins; nucleosides
such as adenosine and nucleotides such as adenosine diphosphate
(ADP) and adenosine triphosphate (ATP);
neurotransmitter/neuromodulators such as acetylcholine and
5-hydroxytryptamine (serotonin/5-HT); histamine and catecholamines
such as adrenalin and noradrenalin; lipid molecules such as
sphingosine-1-phosphate and lysophosphatidic acid; amino acids such
as arginine and lysine; peptides such as the bradykinins, substance
P and calcium gene-related peptide (CGRP), and proteins such as
insulin, vascular endothelial growth factor (VEGF), and
thrombin.
[0146] As illustrated in FIG. 2, a variety of bioactive agents,
coating molecules and ligands for bioactive agents can be attached,
for example covalently, to the surface of the polymer particles.
Bioactive agents, such as targeting antibodies, polypeptides (e.g.,
antigens) and drugs, and the like, can be covalently conjugated to
the surface of the polymer particles. In addition, coating
molecules, such as polyethylene glycol (PEG) as a ligand for
attachment of antibodies or polypeptides or phosphatidylcholine
(PC) as a means of blocking attachment sites on the surface of the
particles to prevent the particles from sticking to non-target
biological molecules and surfaces in the patient may also be
surface-conjugated (FIG. 3).
[0147] For example, small proteinaceous motifs, such as the B
domain of bacterial Protein A and the functionally equivalent
region of Protein G are known to bind to, and thereby capture,
antibody molecules by the Fc region. Such proteinaceous motifs can
be attached to the polymers, especially to the surface of the
polymer particles. Such molecules will act, for example, as ligands
to attach antibodies for use as targeting ligands or to capture
antibodies to hold precursor cells or capture cells out of the
patient's blood stream. Therefore, the antibody types that can be
attached to polymer coatings using a Protein A or Protein G
functional region are those that contain an Fc region. The capture
antibodies will in turn bind to and hold precursor cells, such as
progenitor cells, near the polymer surface while the precursor
cells, which are preferably bathed in a growth medium within the
polymer, secrete various factors and interact with other cells of
the subject. In addition, one or more bioactive agents dispersed in
the polymer particles, such as the bradykinins, may activate the
precursor cells.
[0148] In addition, bioactive agents for attaching precursor cells
or for capturing progenitor endothelial cells (PECs) from the
subject's blood are monoclonal antibodies directed against a known
precursor cell surface marker. For example, complementary
determinants (CDs) that have been reported to decorate the surface
of endothelial cells include CD3 1, CD34, CD 102, CD105, CD106,
CD109, CDw130, CD141, CD142, CD143, CD144, CDw145, CD146, CD147,
and CD166. These cell surface markers can be of varying specificity
and the degree of specificity for a particular cell/developmental
type/stage is in many cases not fully characterized. In addition
these cell marker molecules against which antibodies have been
raised will overlap (in terms of antibody recognition) especially
with CDs on cells of the same lineage: monocytes in the case of
endothelial cells. Circulating endothelial progenitor cells are
some way along the developmental pathway from (bone marrow)
monocytes to mature endothelial cells. CDs 106, 142 and 144 have
been reported to mark mature endothelial cells with some
specificity. CD34 is presently known to be specific for progenitor
endothelial cells and therefore is currently preferred for
capturing progenitor endothelial cells out of blood in the site
into which the polymer particles are implanted for local delivery
of the active agents. Examples of such antibodies include
single-chain antibodies, chimeric antibodies, monoclonal
antibodies, polyclonal antibodies, antibody fragments, Fab
fragments, IgA, IgG, IgM, IgD, IgE and humanized antibodies.
[0149] The following additional bioactive agents and small molecule
drugs will be particularly effective for dispersion within the
invention polymer particle compositions, whether sized to form a
time release biodegradable polymer depot for local delivery of the
bioactive agents, or sized for entry into systemic circulation, as
described herein. The bioactive agents that are dispersed in the
polymer particles used in the invention delivery compositions and
methods of treatment will be selected for their suitable
therapeutic or palliative effect in treatment of a disease of
interest, or symptoms thereof.
[0150] In one embodiment, the suitable bioactive agents are not
limited to, but include, various classes of compounds that
facilitate or contribute to wound healing when presented in a
time-release fashion. Such bioactive agents include wound-healing
cells, including certain precursor cells, which can be protected
and delivered by the biodegradable polymer particles in the
invention compositions. Such wound healing cells include, for
example, pericytes and endothelial cells, as well as inflammatory
healing cells. To recruit such cells to the site of a polymer depot
in vivo, the polymer particles used in the invention delivery
compositions and methods of treatment can include ligands for such
cells, such as antibodies and smaller molecule ligands, that
specifically bind to "cellular adhesion molecules" (CAMs).
Exemplary ligands for wound healing cells include those that
specifically bind to Intercellular adhesion molecules (ICAMs), such
as ICAM-1 (CD54 antigen); ICAM-2 (CD102 antigen); ICAM-3 (CD50
antigen); ICAM-4 (CD242 antigen); and ICAM-5; Vascular cell
adhesion molecules (VCAMs), such as VCAM-1(CD106 antigen)]; Neural
cell adhesion molecules (NCAMs), such as NCAM-1 (CD56 antigen); or
NCAM-2; Platelet endothelial cell adhesion molecules PECAMs, such
as PECAM-1 (CD31 antigen); Leukocyte-endothelial cell adhesion
molecules (ELAMs), such as LECAM-1; or LECAM-2 (CD62E antigen), and
the like.
[0151] In another aspect, the suitable bioactive agents include
extra cellular matrix proteins, macromolecules that can be
dispersed into the polymer particles used in the invention delivery
compositions, e.g., attached either covalently or non-covalently.
Examples of useful extra-cellular matrix proteins include, for
example, glycosaminoglycans, usually linked to proteins
(proteoglycans), and fibrous proteins (e.g., collagen; elastin;
fibronectins and laminin). Bio-mimics of extra-cellular proteins
can also be used. These are usually non-human, but biocompatible,
glycoproteins, such as alginates and chitin derivatives. Wound
healing peptides that are specific fragments of such extra-cellular
matrix proteins and/or their bio-mimics can also be used as the
bioactive agent.
[0152] Proteinaceous growth factors are an additional category of
bioactive agents suitable for dispersion in the polymer particles
used in the invention delivery compositions and methods of
treatment described herein. Such bioactive agents are effective in
promoting wound healing and other disease states as is known in the
art. For example, Platelet Derived Growth Factor-BB (PDGF-BB),
Tumor Necrosis Factor-alpha (TNF-.alpha.), Epidermal Growth Factor
(EGF), Keratinocyte Growth Factor (KGF), Thymosin B4; and, various
angiogenic factors such as vascular Endothelial Growth Factors
(VEGFs), Fibroblast Growth Factors (FGFs), Tumor Necrosis
Factor-beta (TNF -beta), and Insulin-like Growth Factor-1 (IGF-1).
Many of these proteinaceous growth factors are available
commercially or can be produced recombinantly using techniques well
known in the art.
[0153] Alternatively, expression systems comprising vectors,
particularly adenovirus vectors, incorporating genes encoding a
variety of biomolecules can be dispersed in the polymer particles
for timed release delivery. Method of preparing such expression
systems and vector are well known in the art. For example,
proteinaceous growth factors can be dispersed into the invention
polymer particles for administration of the growth factors either
to a desired body site for local delivery by selection of particles
sized to form a polymer depot or systemically by selection of
particles of a size that will enter the circulation. The growth
factors such as VEGFs, PDGFs, FGF, NGF, and evolutionary and
functionally related biologics, and angiogenic enzymes, such as
thrombin, may also be used as bioactive agents in the
invention.
[0154] Small molecule drugs are an additional category of bioactive
agents suitable for dispersion in the polymer particles used in the
invention delivery compositions and methods of treatment described
herein. Such drugs include, for example, antimicrobials and
anti-inflammatory agents as well as certain healing promoters, such
as, for example, vitamin A and synthetic inhibitors of lipid
peroxidation.
[0155] A variety of antibiotics can be dispersed in the polymer
particles used in the invention delivery compositions to indirectly
promote natural healing processes by preventing or controlling
infection. Suitable antibiotics include many classes, such as
aminoglycoside antibiotics or quinolones or beta-lactams, such as
cefalosporins, e.g., ciprofloxacin, gentamycin, tobramycin,
erythromycin, vancomycin, oxacillin, cloxacillin, methicillin,
lincomycin, ampicillin, and colistin. Suitable antibiotics have
been described in the literature.
[0156] Suitable antimicrobials include, for example, Adriamycin
PFS/RDF.RTM. (Pharmacia and Upjohn), Blenoxane.RTM. (Bristol-Myers
Squibb Oncology/Immunology), Cerubidine.RTM. (Bedford),
Cosmegen.RTM. (Merck), DaunoXome.RTM. (NeXstar), Doxil.RTM.
(Sequus), Doxorubicin Hydrochloride.RTM. (Astra), Idamycin.RTM. PFS
(Pharmacia and Upjohn), Mithracin.RTM.) (Bayer), Mitamycin.RTM.)
(Bristol-Myers Squibb Oncology/Immunology), Nipen.RTM. (SuperGen),
Novantrone.RTM. (Immunex) and Rubex.RTM. (Bristol-Myers Squibb
Oncology/Immunology). In one embodiment, the peptide can be a
glycopeptide. "Glycopeptide" refers to oligopeptide (e.g.
heptapeptide) antibiotics, characterized by a multi-ring peptide
core optionally substituted with saccharide groups, such as
vancomycin.
[0157] Examples of glycopeptides included in this category of
antimicrobials may be found in "Glycopeptides Classification,
Occurrence, and Discovery," by Raymond C. Rao and Louise W.
Crandall, ("Bioactive agents and the Pharmaceutical Sciences"
Volume 63, edited by Ramakrishnan Nagarajan, published by Marcal
Dekker, Inc.). Additional examples of glycopeptides are disclosed
in U.S. Pat. Nos. 4,639,433; 4,643,987; 4,497,802; 4,698,327,
5,591,714; 5,840,684; and 5,843,889; in EP 0 802 199; EP 0 801 075;
EP 0 667 353; WO 97/28812; WO 97/38702; WO 98/52589; WO 98/52592;
and in J. Amer. Chem. Soc., 1996, 118, 13107-13108; J. Amer. Chem.
Soc., 1997, 119, 12041-12047; and J. Amer. Chem. Soc., 1994, 116,
4573-4590. Representative glycopeptides include those identified as
A477, A35512, A40926, A41030, A42867, A47934, A80407, A82846,
A83850, A84575, AB-65, Actaplanin, Actinoidin, Ardacin, Avoparcin,
Azureomycin, Balhimyein, Chloroorientiein, Chloropolysporin,
Decaplanin, -demethylvancomycin, Eremomycin, Galacardin,
Helvecardin, Izupeptin, Kibdelin, LL-AM374, Mannopeptin, MM45289,
MM47756, MM47761, MM49721, MM47766, MM55260, MM55266, MM55270,
MM56597, MM56598, OA-7653, Orenticin, Parvodicin, Ristocetin,
Ristomycin, Synmonicin, Teicoplanin, UK-68597, UD-69542, UK-72051,
Vancomycin, and the like. The term "glycopeptide" or "glycopeptide
antibiotic" as used herein is also intended to include the general
class of glycopeptides disclosed above on which the sugar moiety is
absent, i.e. the aglycone series of glycopeptides. For example,
removal of the disaccharide moiety appended to the phenol on
vancomycin by mild hydrolysis gives vancomycin aglycone. Also
included within the scope of the term "glycopeptide antibiotics"
are synthetic derivatives of the general class of glycopeptides
disclosed above, included alkylated and acylated derivatives.
Additionally, within the scope of this term are glycopeptides that
have been further appended with additional saccharide residues,
especially aminoglycosides, in a manner similar to vancosamine.
[0158] The term "lipidated glycopeptide" refers specifically to
those glycopeptide antibiotics that have been synthetically
modified to contain a lipid substituent. As used herein, the term
"lipid substituent" refers to any substituent contains 5 or more
carbon atoms, preferably, 10 to 40 carbon atoms. The lipid
substituent may optionally contain from I to 6 heteroatoms selected
from halo, oxygen, nitrogen, sulfur, and phosphorous. Lipidated
glycopeptide antibiotics are well known in the art. See, for
example, in U.S. Pat. Nos. 5,840,684, 5,843,889, 5,916,873,
5,919,756, 5,952,310, 5,977,062, 5,977,063, EP 667, 353, WO
98/52589, WO 99/56760, WO 00/04044, WO 00/39156, the disclosures of
which are incorporated herein by reference in their entirety.
[0159] Anti-inflammatory bioactive agents are also useful for
dispersion in polymer particles used in invention compositions and
methods. Depending on the body site and disease to be treated, such
anti-inflammatory bioactive agents include, e.g. analgesics (e.g.,
NSAIDS and salicyclates), steroids, antirheumatic agents,
gastrointestinal agents, gout preparations, hormones
(glucocorticoids), nasal preparations, ophthalmic preparations,
otic preparations (e.g., antibiotic and steroid combinations),
respiratory agents, and skin & mucous membrane agents. See,
Physician's Desk Reference, 2001 Edition. Specifically, the
anti-inflammatory agent can include dexamethasone, which is
chemically designated as (119,161)-9-fluro- b
11,17,21-trihydroxy-16-methylpregna-1,4-diene-3,20-dione.
Alternatively, the anti-inflammatory bioactive agent can be or
include sirolimus (rapamycin), which is a triene macrolide
antibiotic isolated from Streptomyces hygroscopicus.
[0160] The polypeptide bioactive agents included in the invention
compositions and methods can also include "peptide mimetics." Such
peptide analogs, referred to herein as "peptide mimetics" or
"peptidomimetics," are commonly used in the pharmaceutical industry
with properties analogous to those of the template peptide
(Fauchere, J. (1986) Adv. Bioactive agent Res., 15:29; Veber and
Freidinger (1985) TINS p. 392; and Evans et al. (1987) J. Med.
Chem., 30:1229) and are usually developed with the aid of
computerized molecular modeling. Generally, peptidomimetics are
structurally similar to a paradigm polypeptide (i.e., a polypeptide
that has a biochemical property or pharmacological activity), but
have one or more peptide linkages optionally replaced by a linkage
selected from the group consisting of: --CH.sub.2NH--,
--CH.sub.2S--, CH.sub.2--CH.sub.2--, --CH=CH-- (cis and trans),
--COCH.sub.2--, --CH(OH)CH.sub.2--, and --CH.sub.2SO--, by methods
known in the art and further described in the following references:
Spatola, A.F. in "Chemistry and Biochemistry of Amino Acids,
Peptides, and Proteins," B. Weinstein, eds., Marcel Dekker, New
York, p. 267 (1983); Spatola, A.F., Vega Data (March 1983), Vol. 1,
Issue 3, "Peptide Backbone Modifications" (general review); Morley,
J.S., Trends. Pharm. Sci., (1980) pp.463-468 (general review);
Hudson, D. et al., Int. J. Pept. Prot. Res., (1979) 14:177-185
(--CH.sub.2NH--, CH.sub.2CH.sub.2--); Spatola, A.F. et al., Life
Sci., (1986) 38:1243-1249 (--CH.sup.2--S--); Harm, M. M., J. Chem.
Soc. Perkin Trans I (1982) 307-314 (--CH=CH--, cis and trans);
Almquist, R.G. et al., J. Med. Chem., (1980) 23:2533
(--COCH.sub.2--); Jennings-Whie, C. et al., Tetrahedron Lett.,
(1982) 23:2533 (--COCH.sub.2--); Szelke, M. et al., European
Appln., EP 45665 (1982) CA: 97:39405 (1982) (--CH(OH)CH.sub.2--);
Holladay, M. W. et al., Tetrahedron Lett., (1983) 24:4401-4404
(--C(OH)CH.sub.2--); and Hruby, V.J., Life Sci., (1982) 31:189-199
(--CHC.sub.2--S--). Such peptide mimetics may have significant
advantages over natural polypeptide embodiments, including, for
example: more economical production, greater chemical stability,
enhanced pharmacological properties (half-life, absorption,
potency, efficacy, etc.), altered specificity (e.g., a
broad-spectrum of biological activities), reduced antigenicity, and
others.
[0161] Additionally, substitution of one or more amino acids within
a peptide (e.g., with a D-Lysine in place of L-Lysine) may be used
to generate more stable peptides and peptides resistant to
endogenous peptidases. Alternatively, the synthetic polypeptides
covalently bound to the biodegradable polymer, can also be prepared
from D-amino acids, referred to as inverso peptides. When a peptide
is assembled in the opposite direction of the native peptide
sequence, it is referred to as a retro peptide. In general,
polypeptides prepared from D-amino acids are very stable to
enzymatic hydrolysis. Many cases have been reported of preserved
biological activities for retro-inverso or partial retro-inverso
polypeptides (U.S. Pat. No. 6,261,569 B 1 and references therein ;
B. Fromme et al, Endocrinology (2003)144:3262-3269.
[0162] It is readily apparent that the subject invention can be
used to prevent or treat a wide variety of diseases or symptoms
thereof.
[0163] Following preparation of the polymer particles loaded with
bioactive agent, the composition can be lyophilized and the dried
composition suspended in an appropriate media prior to
administration.
[0164] Any suitable and effective amount of the at least one active
agent can be released with time from the polymer particles
(including those in a polymer depot formed in vivo) and will
typically depend, e.g., on the specific polymer, type of particle
or polymer/bioactive agent linkage, if present. Typically, up to
about 100% of the polymer particles can be released from a polymer
depot formed in vivo by particles sized to avoid circulation.
Specifically, up to about 90%, up to 75%, up to 50%, or up to 25%
thereof can be released from the polymer depot. Factors that
typically affect the release rate from the polymer are the nature
and amount of the polymerfbioactive agent, the types of
polymer/bioactive agent linkage, and the nature and amount of
additional substances present in the formulation.
[0165] Once the invention polymer particle delivery composition is
made, as above, compositions are formulated for subsequent
intrapulmonary, gastroenteral, subcutaneous, intramuscular, into
the central nervous system, intraperitoneum or intraorgan delivery.
The compositions will generally include one or more
"pharmaceutically acceptable excipients or vehicles" appropriate
for oral, mucosal or subcutaneous delivery, such as water, saline,
glycerol, polyethylene glycol, hyaluronic acid, ethanol, etc.
Additionally, auxiliary substances, such as wetting or emulsifying
agents, pH buffering substances, flavorings, and the like, may be
present in such vehicles.
[0166] For example, intranasal and pulmonary formulations will
usually include vehicles that neither cause irritation to the nasal
mucosa nor significantly disturb ciliary function. Diluents such as
water, aqueous saline or other known substances can be employed
with the subject invention. The intrapulmonary formulations may
also contain preservatives such as, but not limited to,
chlorobutanol and benzalkonium chloride. A surfactant may be
present to enhance absorption by the nasal mucosa.
[0167] For rectal and urethral suppositories, the vehicle
composition will include traditional binders and carriers, such as,
cocoa butter (theobroma oil) or other triglycerides, vegetable oils
modified by esterification, hydrogenation and/or fractionation,
glycerinated gelatin, polyalkaline glycols, mixtures of
polyethylene glycols of various molecular weights and fatty acid
esters of polyethylene glycol.
[0168] For vaginal delivery, the formulations of the present
invention can be incorporated in pessary bases, such as those
including mixtures of polyethylene triglycerides, or suspended in
oils such as corn oil or sesame oil, optionally containing
colloidal silica. See, e.g., Richardson et al., Int. J. Pharm.
(1995) 115:9-15.
[0169] For a further discussion of appropriate vehicles to use for
particular modes of delivery, see, e.g., Remington: The Science and
Practice of Pharmacy, Mack Publishing Company, Easton, Pa., 19th
edition, 1995. One of skill in the art can readily determine the
proper vehicle to use for the particular bioactive agent/polymer
particle combination, size of particle and mode of
administration.
[0170] In addition to treatment of humans, the invention polymer
particle delivery compositions are also intended for use in
veterinary treatment of a variety of mammalian patients, such as
pets (for example, cats, dogs, rabbits, and ferrets), farm animals
(for example, swine, horses, mules, dairy and meat cattle) and race
horses.
[0171] The compositions used in the invention methods optionally
may comprise an "effective amount" of the active agent(s) of
interest or of a therapeutic di-acid or diol incorporated into the
backbone of the PEA, PEUR or PEU polymer. That is, an amount of an
active agent or therapeutic di-acid or diol may be included in the
compositions that will cause the subject to produce a sufficient
therapeutic or palliative response in order to prevent, reduce or
eliminate symptoms. The exact amount necessary will vary, depending
on the subject being treated; the age and general condition of the
subject to be treated; the capacity of the subject's immune system,
the degree of protection desired; the severity of the condition
being treated; the particular active agent selected and mode of
administration of the composition, among other factors. An
appropriate effective amount can be readily determined by one of
skill in the art. Thus, an "effective amount" will fall in a
relatively broad range that can be determined through routine
trials. For example, for purposes of the present invention, an
effective amount will typically range from about 1 .mu.g to about
100 mg, for example from about 5 .mu.g to about 1 mg, or about 10
.mu.g to about 500 .mu.g of the active agent delivered per
dose.
[0172] Once formulated, the invention polymer particle delivery
compositions are administered orally, mucosally, or by
subcutaneously or intramuscular injection, and the like, using
standard techniques. See, e.g., Remington: The Science and Practice
of Pharmacy, Mack Publishing Company, Easton, Pa., 19th edition,
1995, for mucosal delivery techniques, including intranasal,
pulmonary, vaginal and rectal techniques, as well as European
Publication No. 517,565 and Illum et al., J. Controlled Rel. (1994)
29:133-141, for techniques of intranasal administration.
[0173] Dosage treatment may be a single dose of the invention
polymer particle delivery composition, or a multiple dose schedule
as is known in the art. The dosage regimen, at least in part, will
also be determined by the need of the subject and be dependent on
the judgment of the practitioner. Furthermore, if prevention of
disease is desired, the polymer particle delivery composition is
generally administered prior to primary disease manifestation, or
symptoms of the disease of interest. If treatment is desired, e.g.,
the reduction of symptoms or recurrences, the polymer particle
delivery compositions are generally administered subsequent to
primary disease manifestation.
[0174] The formulations can be tested in vivo in a number of animal
models developed for the study of oral subcutaneous or mucosal
delivery. For example, the conscious sheep model is an
art-recognized model for testing nasal delivery of substances See,
e.g., Longenecker et al., J. Pharm. Sci. (1987) 76:351-355 and
Illum et al., J. Controlled Rel. (1994) 29:133-141. The polymer
particle delivery composition, generally in powdered, lyophilized
form, is blown into the nasal cavity. Blood samples can be assayed
for active agent using standard techniques, as known in the
art.
[0175] The following examples are meant to illustrate, but not to
limit the invention.
EXAMPLE 1
Preparation of PEA-Ac-Bz nanoparticles and particles by the single
emulsion method
[0176] PEA polymer of structure (I) containing acetylated ends and
benzylated COOH pendent groups (designated as PEA.Ac.Bz) (25 mg)
was dissolved in 1 ml of DCM and added to 5 ml of 0.1% DHPC in
aqueous solution while stirring. After rotary-evaporation, PEA-AcBz
emulsion with particle sizes ranged from 20 nm to 100 .mu.m, was
obtained. The higher the stir rate, the smaller the sizes of
particles. Particle size is controlled by molecular weight of the
polymer, solution concentration and equipment such as
microfluidizer, ultrasound sprayer, sonicator, and mechanical or
magnetic stirrer.
Preparation of PEA-AcBz particles containing a pain killer
[0177] PEA.AcBz (25 mg) and Bupivicane (5 mg) were dissolved in 1
ml of DCM and the solution was added to 5 ml of 0.1% DHPC aqueous
solution while homogenizing. Using a rotary evaporator, a PEA.Ac.Bz
emulsion with average particle size ranging from 0.5 .mu.m to 1000
.mu.m, preferentially, from 1 .mu.m to about 20 .mu.m, have been
made.
EXAMPLE 2
Preparation of polymer particles using a double emulsion method
[0178] Particles were prepared using a double emulsion technique in
two steps: in the first step, PEA.Ac.Bz (25 mg) was dissolved in 1
ml of DCM, and then 50 .mu.l of 10% surfactant
diheptanoyl-phosphatidylcholine (DHPC), was added. The mixture was
vortexed at room temperature to form a Water/Oil (W/O) primary
emulsion. In the second step, the primary emulsion was added slowly
into a 5 ml solution of 0.5% DHPC while homogenizing the mixed
solution. After 1 min of homogenization, the emulsion was
rotary-evaporated to remove DCM to obtain a Water/Oil/Water double
emulsion. The generated double emulsion had suspended polymer
particles with sizes ranging from 0.5 .mu.m to 1000 .mu.m, with
most about 1 .mu.m to 10 .mu.m. Reducing such factors as the amount
of surfactant, the stir speed and the volume of water, tends to
increase the size of the particles.
EXAMPLE 3
Preparation of PEA particles encapsulating an antibody using a
double emulsion method
[0179] 1Particles were prepared using the double emulsion technique
by two steps: in the first step, PEA.Ac.Bz (25 mg) was dissolved in
1ml of DCM, and then 50 of aqueous solution containing 60 .mu.g of
anti-Icam-1 antibody and 4.0 mg of DHPC were added. The mixture was
vortexed at room temperature to form a Water/Oil primary emulsion.
In the second step, the primary emulsion was added slowly into 5 ml
of 0.5 % DHPC solution while homogenizing. After 1min of
homogenization, the emulsion was rotary-evaporated to remove DCM to
obtain particles having a Water/Oil/Water (W/O/W) double emulsion
structure. About 75% to 98% of antibody was encapsulated by using
this double emulsion technique.
EXAMPLE 4
Preparation of particles having a triple emulsion structure,
wherein one or more primary particles are encapsulated together
within a polymer covering to form secondary microparticles.
[0180] Particles having a triple emulsion structure have been
prepared by the following two different routes:
[0181] Multi-particle Encapsulation In the first route, primary
particles were prepared using a standard procedure for single
phase, PEA.Ac.H (polymer of structure (I) containing acetylated
ends and free COOH pendent groups) nanoparticles were prepared to
afford a stock sample, ranging from about 1.0 mg to about 10 mg/ml
(polymer per aqueous unit). In addition, a solution of the
PEA.Ac.Bz stock sample, with a 20% surfactant weight amount wherein
the 20% is calculated as (milligrams of surfactant)/(milligrams of
PEA.Ac.Bz+milligrams of surfactant) was prepared. Various
surfactants were explored, with the most successful being
1,2-Diheptanoyl-sn-glycero-3-phosphocholine (DHPC). The stock
sample of PEA-Ac-H nanoparticles was injected into a solution of
PEA-AcBz polymer in DCM. A typical example was as follows:
TABLE-US-00003 Nanoparticle Stock Solution 100 .mu.l Dissolved
PEA-AcBz 20 mg CH.sub.2Cl.sub.2 2 ml Surfactant Amount 5 mg
This first addition was referred to as the "primary emulsion." The
sample was allowed to stir by shake plate for 5-20 minutes. Once
sufficient homogeneity was observed, the primary emulsion was
transferred into a canonical vial that contains 0.1% of a surface
stabilizer in aqueous media (5-10 ml). These contents are referred
to as the "external aqueous phase". Using a homogenizer at low
speed (5000 - 6000 RPM), the primary emulsion was slowly pipetted
into the external aqueous phase, while undergoing low speed
homogenization. After 3-5 minutes at 6000 RPM, the total sample
(referred to as "the secondary emulsion") was concentrated in
vacuo, to remove the DCM, while encapsulating the PEA-Ac-H
nanoparticles within a continuous PEA-Ac-Bz matrix.
[0182] Preparation of Small Molecules loaded into secondary polymer
coatings. In the second route for preparing particles having a
triple emulsion structure, the procedure described above for making
single emulsion particles was followed for the first step. In the
final step, a polymeric coating encapsulating the single emulsion
particles (i.e., the water in oil phase) was then prepared.
[0183] More particularly, water in oil phase (primary emulsion) was
created. In this case,, a concentrated mixture of drug (5 mg) a
surfactant (such as DHPC) was prepared first using a minimum volume
of water. Then the concentrated mixture was added into a DCM
solution of PEA-AcBz, and was subjected to a sonication bath for
5-10 minutes. Once sufficient homogeneity was observed, the
contents were added into 5 ml of water while homogenizing. After
removal of DCM by vacuum evaporation, a triple emulsion of
PEA.Ac.Bz containing aqueous dispersion of drug was obtained.
[0184] In another example, a stock sample of PEA.Ac.H nanoparticles
with drug was prepared. PEA.Ac.H(25 mg) and drug (5 mg) were
dissolved in 2 ml of DCM and mixed with 5 ml of water by sonication
for 5.about.10 minutes. Once sufficient homogeneity was observed,
the contents were rotoevaporated to remove DCM. A typical example
of preparations made using this method had the following contents.
TABLE-US-00004 PEA.Ac.H 25 mg CH.sub.2Cl.sub.2 2 ml H.sub.2O 5 ml
Small Molecule Drug 5 mg
The above preparation then was subjected to overnight evaporation
in a Teflon disk to further reduce the water and yield a volume of
approximately 2ml. An exterior polymer coating, i.e. 25mg PEA.Ac.Bz
in up to 5 ml of DCM, was combined with the primary emulsion and
the entire secondary emulsion was stirred by vortexing for no more
than 1 minute. Finally, the secondary emulsion was transferred to
an aqueous media (10-15 ml) containing 0.1% surface stabilizer,
homogenized at 6000 RPM for 5 minutes, and concentrated again in
vacuo to remove the second phase of DCM, thus yielding particles
having a triple emulsion structure as illustrated in FIG. 6.
EXAMPLE 5
[0185] Drug Capture (50%) by Triple Emulsion The following example
illustrates loading of a small molecule drug in a polymer coating.
PEA particles containing a high loading of bupivacaine HC1 were
fabricated by the triple emulsion technique, using a minimal amount
of H.sub.2O in the primary emulsion, as compared to the double
emulsion protocol (roughly half of the water was used). To
stabilize the structure allowing for the reduction in the aqueous
phase, the surface stabilizer that aides in solubilizing the drug
in the aqueous droplets is dissolved itself in the internal aqueous
phase before the drug is added to the internal aqueous phase. In
particular, DHPC (amount below) was first dissolved into 100 .mu.l
H2O; then 50mg of drug was added to the phase. This technique
allowed for loading of higher doses of drug in the particles, with
even less water than was used in making the same sized double
emulsion particles. The following parameters were followed during
synthesis: TABLE-US-00005 weight Reagent Mg equivalence PEA-AcBz 50
50% Bupivacaine 50 50% HCL DHPC 12.4 20% of polymer
CH.sub.2Cl.sub.2 2.5 ml (2% PEA in (solvent) solvent) H2O 100 .mu.l
(2:1 drug)
[0186] TABLE-US-00006 weight Reagent Mg equivalence DHPC 16 24% of
polymer H2O 5 ml 2/1 ratio to solvent
EXAMPLE 6
Process for making triblock copolymer micelles with therapeutic
agents
[0187] First, A-B-A type triblock copolymer molecules are formed by
conjugating a chain of hydrophobic PEA or PEUR polymer at the
center with water soluble polymer chains containing alternating
units of PEG and at least one ionizable amino acid, such as lysine
or glutamate, at both ends. The triblock copolymer is then
purified.
[0188] Then micelles are made using the triblock copolymer. The
triblock copolymer and at least one bioactive agent, such as a
small molecule drug, a protein, peptide, a lipid, a sugar, DNA cDNA
or RNA, are dissolved in aqueous solution, preferably in a saline
aqueous solution whose pH has been adjusted to a value chosen in
such a way that at least a portion of the ionizable amino acids in
the water soluble chains is in ionized form to produce a dispersion
of the triblock polymer in aqueous solution. Surface stabilizer,
such as surfactant or lipid, is added to the dispersion to separate
and stabilize particles to be formed. The mixed solution is then
stirred with a mechanical or magnetic stirrer, or sonicator.
Micelles will be formed in this way, as shown in FIG. 10, with
water-soluble sections mainly on the shell, and hydrophobic
sections in the core, maintaining the integrity of micellar
particles. The micelles have high porosity for loading of the
active agents. Protein and other biologics can be attracted to the
charged areas in the water-soluble sections. Micellar particles
formed are in the size range from about 20nm to about 200 nm.
EXAMPLE 7
Polymer coating on particles made of different polymer mixed with
drug
[0189] Use of single emulsion leaves the problem that, although
particles can be made very small (from 20 nm to 200 nm), the drug
is matrixed in the particles and may elute too quickly. For double
and triple emulsion particles, the particles are larger than is
prepared by the single emulsion technique due to the aqueous
solution inside. However, if the same polymer is used for coating
the particles as is used to matrix the drug, the solvent used in
making the third emulsion (the polymer coating) will dissolve the
matrixed particles, and the coating will become part of the matrix
(with drugs in it). To solve this problem, a different polymer than
is used to matrix the drug is used to make the coating of the
particles and the solvent used in making the polymer coating is
selected to be one in which the matrix polymer will not
dissolve.
[0190] For example, PEA can be dissolved in ethanol but PLA cannot.
Therefore, PEA can be used to matrix the drug and PLA can be used
as the coating polymer, or vice versa. In another example, ethanol
can dissolve PEA but not PEUR and acetone can dissolve PEUR but
cannot dissolve PEA. Therefore, PEUR can be used to matrix the drug
and PEA can be used as the coating polymer, or vice versa.
[0191] Therefore, the general process to be used is as follows.
Using polymer A, prepare particles in solution (aqueous if polymer
A is PEA or PEUR) using a single emulsion procedure to matrix drug
or other bioactive agent in the polymer particles. Dry out the
solvent by lyophilization to obtain dry particles. Disperse the dry
particles into a solution of polymer B in a solvent that does not
dissolve the polymer A particles. Emulsify the mixture in aqueous
solution. The resulting particles will be nanoparticles with a
coating of polymer B on particles of polymer A, which contain
matrixed drug.
EXAMPLE 8
[0192] In this example a PEA polymer containing a residue of
.beta.-Estradiol in the main PEA polymer backbone was prepared.
[0193] Materials 17-.beta.-estradiol
(estra-1,3,5(10)-triene-3,17,.beta.-diol), L-lysine, benzyl
alcohol, sebacoyl chloride, 1,6-Hexanediol, p-nitrophenol,
triethylamine, 4-N,N-(dimethylamino)pyridine (DMAP),
N,N'-dicyclohexylcarbodiimide (DCC), anhydrous
N,N-dimethylformamide (DMF), anhydrous dichloromethane (DCM),
trifluoroacetic acid (TFA), p-toluenesulfonic acid monohydrate
(Aldrich Chemical Co., Milwaukee, WI), anhydrous toluene,
Boc-L-leucine monohydrate (Calbiochem-Novabiochem, San Diego, CA)
were used without further purification. Other solvents, ether and
ethyl acetate (Fisher Chemical, Pittsburgh, PA).
[0194] Synthesis of Monomers and Polymers Synthesis of bioactive
PEAs involved three basic steps: (1) synthesis of
bis-electrophyles: di(p-nitrophenyl) esters of dicarboxylic acid
(here of sebacic acid, compound 1); (2) synthesis of
bis-nucleophiles: di-p-toluenesulfonic acid salts (or di-TFA salt)
of bis(L-leucine)-diol-diesters (compounds 3 and 5) and of L-lysine
benzyl ester (compound 2); and (3) solution polycondensation of the
monomers obtained in steps (1) and (2).
[0195] Synthesis of di-p-nitrophenyl esters of sebacic acid
(compound 1) Di-p-nitrophenyl ester of sebacic acid was prepared by
reacting of sebacoyl chloride with p-nitrophenol as described
previously (Katsarava et al. J Polym. Sci. Part A: Polym. Chem.
(1999) 37. 391-407) (scheme IV): ##STR29##
[0196] Di-p-toluenesulfonic acid salt of L-lysine benzyl ester was
prepared as described earlier (U.S. Pat. No. 6,503,538) by
refluxing of benzyl alcohol, toluenesulfonic acid monohydrate and
L-lysine monohydrochloride in toluene, while applying azeotropic
removal of generated water (scheme V). ##STR30##
[0197] Synthesis of acid salts of bis(.alpha.-amino acid) diesters
(3), (5) Di-p-toluenesulfonic acid salt of bis(L-leucine) hexane-1
,6-diester (compound 3) was prepared by modified procedure of the
previously published method as shown in scheme 3.
[0198] L-Leucine (0.132 mol), p-toluenesulfonic acid monohydrate
(0.132 mol) and 1,6-hexanediol (0.06 mol) in 250 mL of toluene were
placed in a flask equipped with a Dean-Stark apparatus and overhead
stirrer. The heterogeneous reaction mixture was heated to reflux
for about 12 h until 4.3 mL (0.24 mol) of water evolved. The
reaction mixture was then cooled to room temperature, filtered,
washed with acetone, and recrystallized twice from methanol/toluene
2:1 mixture. Yields and Mp were identical to published data
(Katsarava et al., supra) (see scheme VI). ##STR31## A di-TFA salt
of bis-L-leucine-.beta.-estradiol-diester (compound 5) was prepared
by a two step reaction. 17.beta.-Estradiol was first reacted with
Boc-protected L-Leucine, applying carbodiimide mediated
esterification, to form compound 4. In a second step, Boc groups
were deprotected using TFA, converting at the same time into a
di-TFA salt of di-amino monomer (compound 5) (see scheme VII).
##STR32##
[0199] Preparation of
Bis(Boc-L-leucine)estradiol-3,17.beta.-diester (4) 1.5 g (5.51
mmol) of 17,.beta.-estradiol, 3.43 g (13.77 mmol) Boc-L-leucine
monohydrate and 0.055 g (0.28 mmol) of p-toluenesulfonic acid
monohydrate were dissolved into 20 mL of dry N,N-dimethylformamide
at room temperature under a dry nitrogen atmosphere. To this
solution 10 g of molecular sieves were added and stirring continued
for 24 h. Then, 0.067 g of DMAP and 5.4 g of (26.17 mmol) DCC were
introduced into the reaction solution and stirring was continued.
After 6 h (no discoloration of the reaction was observed), 1 mL of
acetic acid was added to destroy the excess of DCC. Precipitated
urea and sieves then were filtered off and filtrate poured in 80 mL
of water. Product was extracted three times with 30 mL of
ethylacetate, dried over sodium sulfate, solvent evaporated, and
the product was subjected to chromatography on a column (7:3
hexanes: ethylacetate). A colorless glassy solid of pure compound 4
obtained in a 2.85 g, 74% yield and 100% purity (TLC) and was
further converted to compound 5.
[0200] Di-TFA salt of bis(L-leucine)estradiol-3,17.beta.diester
(compound 5). Deprotection of Boc-protected monomer (compound 4)
was carried out substantially quantitatively in 10 mL of dry
dichloromethane, by adding 4 mL of dry TFA. After 2 h of stirring
at room temperature, a homogenous solution was diluted with 300 mL
of anhydrous ether and left in a cold room over night. Precipitated
white crystals were collected, washed twice with ether, and dried
in a vacuum oven at 45 .degree. C. Yield 2.67 g (90%).
Mp=187.5.degree. C.
[0201] Polymer Synthesis. Synthesis of therapeutic PEA was carried
out in DMF in mild conditions (60.degree. C.): 4 eq. activated
di-acid monomer (compound 1) was reacted with combinations of the
di-amino monomers 1.5 eq. (compound 2), 1.5 eq. (compound 5) and 1
eq. of (compound 3).
[0202] Triethylamine 1.46 mL (10.47 mmol) was added at once to the
mixture of monomers (compound 1) (4.986 mmol), (compound 2) (1.246
mmol), (compound 3) (1.869 mmol), (compound 5) (1.869 mmol) in 3 mL
of dry DMF and the solution was heated to 60.degree. C. while
stirring. The reaction vial was kept at the same temperature for 16
h. A yellow viscous solution was formed then was cooled down to
room temperature, diluted with 9 mL of dry DMF, added 0.2 mL of
acetic anhydride, and after 3 h precipitated out three times: first
in water, then from ethanol solution into ethylacetate and lastly,
from chloroform in ethyl acetate. A colorless hydrophobic polymer
was cast as a tough film from chloroform:ethanol (1:1) mixture and
dried in vacuum. Yield: 1.74 g (70%).
[0203] Materials Characterization The chemical structure of
monomers and polymer were characterized by standard chemical
methods. NMR spectra were recorded by a Bruker AMX-500 spectrometer
(Numega R. Labs Inc. San Diego, CA) operating at 500 MHz for
.sup.1H NMR spectroscopy. Deuterated solvents CDCl.sub.3or
DMSO-d.sub.6 (Cambridge Isotope Laboratories, Inc., Andover, MA)
were used with tetramethylsilane (TMS) as internal standard.
[0204] Melting points of synthesized monomers were determined on an
automatic Mettler-Toledo FP62 Melting Point Apparatus (Columbus,
OH). Thermal properties of synthesized monomers and polymers were
characterized on Mettler-Toledo DSC 822e differential scanning
calorimeter. Samples were placed in aluminum pans. Measurements
were carried out at a scanning rate of 10.degree. C./min under
nitrogen flow.
[0205] The number and weight average molecular weights (Mw and Mn)
and molecular weight distribution of synthesized polymer was
determined by Model 515 gel permeation chromatography (Waters
Associates Inc. Milford, MA) equipped with a high pressure liquid
chromatographic pump, a Waters 2414 refractory index detector. 0.1%
of LiCl solution in N,N-dimethylacetamide (DMAc) was used as eluent
(1.0 mL/min). Two Styragel.RTM. HR 5E DMF type columns (Waters)
were connected and calibrated with polystyrene standards.
[0206] Tensile Properties: tensile strength, elongation at break
and Young's Modulus were measured on a tensile strength instrument
(Chatillon TCD200, integrated with a PC (Nexygen.TM. FM
software)(Chatillon, Largo, Fla.) at a crosshead speed of 100
mm/min. The load capacity was 50 lbs. The film (4.times.1.6 cm) had
a dumbbell shape and thickness of about 0.125 mm.
[0207] Results Four different monomers were copolymerized by
polycondensation of activated monomers, affording copoly PEA
containing 17% w/w steroid load on a total polymer weight basis.
Chemical structure of the product therapeutic polymer composition,
containing fragments of 17.beta.-estradiol, L-Leucine,
L-Lysine(OBn), 1,6-hexanediol and sebacic acid is depicted in
Formula (XVII). ##STR33## Three monomers: bis-p-toluenesulfonic
acid salts of L-lysine-benzyl ester (compound 2), bis(L-leucine)
1,6-hexane diester (compound 3), and bis(p-nitrophenyl) sebacate
(compound 1) were prepared according to the literature and
characterized by melting point and proton NMR spectroscopy. Results
were in agreement with those reported in literature.
[0208] In this example a PEA polymer containing a residue of
.beta.-Estradiol in the main polymer backbone was prepared, where
both hydroxyls of the diol steroid were incorporated into monomer
via ester bonds using a carbodiimide technique, with results as
shown in Table 1 above. The final monomer introduced into the
polymerization reaction was a TFA salt. After polycondensation, a
high molecular weight copolymer was obtained. Gel permeation
chromatography yielded an estimated weight average Mw=82,000 and
polydispersity PDI=1.54. The product copolymer was partially
soluble in ethanol (when dry), well soluble in chloroform,
chloroform:ethanol 1:1 mixture, dichloromethane, and in polar
aprotic organic solvents: DMF, DMSO, DMAc.
[0209] Glass transition temperature was detected at Tg=41.degree.
(midpoint, taken from the second heating curve) and a sharp melting
endotherm was detected at 220 .degree. C. by Differential scanning
calorimetry (DSC) analysis. This result leads to the conclusion
that the polymer has semi-crystalline properties.
[0210] The therapeutic polymer formed a tough film when cast from
chloroform solution. Tensile characterization yielded the following
results: Stress at break 28.1 MPa, Elongation 173%, Young's Modulus
715 MPa.
EXAMPLE 9
[0211] This Example illustrates synthesis of a therapeutic PEUR
polymer composition (Formula V) containing a therapeutic diol in
the polymer backbone is illustrated in this example. A first
monomer used in the synthesis is a di-carbonate of a therapeutic
diol with a general ##STR34## chemical structure illustrated by
formula is formed using a known procedure (compound (X) as
described in U.S. Pat. No. 6,503,538) wherein R.sup.5 is
independently (C.sub.6-C.sub.10) aryl (e.g. p-nitrophenol, in this
example), optionally substituted with one or more nitro, cyano,
halo, trifluoromethyl or trifluoromethoxy; and at least some of
p-nitrophenol. At least some of R.sup.6 is a residue of a
therapeutic diol as described herein, depending upon the desired
drug load. In the case where all of R.sup.6 is not the residue of a
therapeutic diol, each diol would first be prepared and purified as
a separate monomer. For example,
di-p-nitrophenyl-3,17b-estradiol-dicarbonate (compound 6) can be
prepared by the method of Scheme 7 below: ##STR35##
Polycondensation of compound X from U.S. Pat. No. 6,503,538 (in our
example compound 6) with the monomers described above yields an
estradiol-based co-poly(ester urethane) PEUR (compound 11):
##STR36## wherein the reaction scheme is as follows ##STR37##
EXAMPLE 10
Monomer synthesis for preparation of PEU polymers
[0212] Preparation of diamine type monomers: di-p-toluenesulfonic
acid salt of L-lysine benzyl ester (L-Lys(OBn), Compound 2) and
di-toluenesulfonic acid salt of bis(L-leucine)-hexane- 1,6-diester,
(compound 3) were described in previous example 8. Preparation of
Di-p-toluenesulfonic acid salt of
bis(L-leucine)-1,4:3,6-dianhydrosorbitol-diester (Compound 7) was
conducted as described previously (Z.Gomurashvili et al. J
Macromol. Sci. -Pure. Appl. Chem. (2000) A37: 215-227). ##STR38##
wherein L-leucine (0.132 mol), p-toluenesulfonic acid monohydrate
(0.135 mol) and isosorbide (0.06 mol) in 250 mL of toluene were
placed in a flask equipped with a Dean-Stark apparatus and overhead
stirrer. The heterogeneous reaction mixture was heated to reflux
for about. 12 h until 4.3 mL (0.24 mol) of water evolved. The
reaction mixture was then cooled to room temperature, filtered,
washed with acetone and recrystallized twice from methanol/toluene
2:1 mix. Yields and Mp were identical to published data
(Z.Gomurashvili et al.supra).
EXAMPLE 11
Preparation of PEU 1-L-Leu-6 (Polymer entry # 2, Table 2)
[0213] To a suspension of 6.89 g (10 mmol) of di-p-toluenesulfonic
acid salt of bis(L-leucine)-1,6-hexanediol-diester in 150 mL of
water, 4,24 g (40 mmol) of anhydrous sodium carbonate was added,
stirred at room temperature for 30 min. and cooled to 2 .degree. C.
to 0 .degree. C. In parallel, a solution of 0,9893 g (10 mmol) of
phosgene in 35 mL of chloroform was cooled to 15 .degree. C. to
10.degree. C. The first solution was placed into a reactor for
interfacial polycondensation and the second solution was quickly
added in bolus and stirred briskly for 15 min. Then the chloroform
layer was separated, dried, over anhydrous Na.sub.2SO.sub.4, and
filtered. The obtained solution was evaporated and the polymer
yield was dried in vacuum at 45.degree. C. Yield was 82%. For
.sup.1H and .sup.13C NMR see FIG. 2 and FIG. 3. Elemental analysis:
for C.sub.19H.sub.34N.sub.20.sub.5, calculated values: C:61.60%, H:
9.25%, N: 7.56%; Found values: C: 61.63%, H: 8.90%, N: 7.60.
EXAMPLE 12
Preparation of PEU 1-L-Leu-DAS (polymer: entry # 5, Table 2)
[0214] ##STR39##
[0215] A cooled solution (ice-bath) of 5 g (6.975 mmole) of bis
(L-leucine)-l ,4:3,6-dianhydrosorbitol-diester (compound 7) and 2.4
g of sodium carbonate in 40 mL of water was prepared. To the cooled
solution, 70 mL of chloroform was added with vigorous stirring and
then 3.7 mL of 20% phosgene solution in toluene (Fluka) was
introduced. Poly(ester urea) formed rapidly with evolution of heat.
After the reaction had been stirred for 10 min, the organic layer
was rotoevaporated and residual polymer was filtered, washed
several times with water, and dried in vacuum over night. Yield of
product was 1.6 g. (57%). Polymer properties are as summarized in
Table 2.
EXAMPLE 13
[0216] This example describes a degradation study conducted to
compare degradation rates over time of a PEU polymer 1-L-Leu-4.
Circular PEU films of 4 cm diameter and 400-500 mg each, were
placed into the glass beakers containing 10 ml of 0.2 M phosphate
buffer solution of pH 7.4 with 4 mg of an enzyme, either
.alpha.-chymotrypsin or lipase, or without enzymes. The glass
vessels were maintained at 37.degree. C. Films were removed from
the enzyme solution after predetermined time, dried up to constant
weights, and weighed. Then the films were placed into the fresh
solution of either enzyme or pure buffer and all the procedures
described above were repeated. Weight changes per unit surface area
of the sample were calculated and represented graphically vs.
biodegradation time. The results of the study showed that the PEU
polymer has a degradation profile that is almost zero order,
corresponding to a surface degradation profile.
[0217] All publications, patents, and patent documents are
incorporated by reference herein, as though individually
incorporated by reference. The invention has been described with
reference to various specific and preferred embodiments and
techniques. However, it should be understood that many variations
and modifications might be made while remaining within the spirit
and scope of the invention.
[0218] Although the invention has been described with reference to
the above examples, it will be understood that modifications and
variations are encompassed within the spirit and scope of the
invention. Accordingly, the invention is limited only by the
following claims.
* * * * *