Patent US2325714A successfully refreshed from Google Patents.
US4230686A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Drug excipient of silicone rubber
Assignee: Bayer Pharma AG
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Filing: 1976-12-23
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Granted: 1980-10-28
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Expires: 1996-12-23
Abstract
Abstract Nontoxic sustained release pharmaceutical compositions containing one or more nonionic, lipophilic drugs in a cured low temperature vulcanizable (LTV) silicone elastomer excipient are prepared substantially free of toxic vulcanizing agents or drug-reactive by-products in the elastomeric material by curing an admixture of the drug or drug containing core, LTV-methylvinylsiloxane units containing linear dimethylpolysiloxane and a dimethylpolysiloxane crosslinking composition containing silicon linked H atoms using a noble metal-based catalyst. The resultant compositions are characterized by good physical properties and a constant rate of drug release in the body over long periods of time.
Inventors
- 👤 Gisela Schopflin
- 👤 Peter Fuchs
- 👤 Karl H. Kolb
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:00
CPC Classifications
A; A61; A61K; A61K9/00; A61K9/70; A61K9/7023; A61K9/703; A61K9/7038; A61K9/7046; A61K9/7069; A61K9/0012; A61K9/0034; A61K9/0036; A61K9/0039; A61K9/20; A61K9/2004; A61K9/2022; A61K9/2031; A61K9/2036; A61K9/28; A61K9/2806; A61K9/2833; A61K9/2853; A61K9/7084; C; C08; C08L; C08L83/00; C08L83/04; C08G; C08G77/00; C08G77/04; C08G77/20
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
152 words
A nontoxic pharmaceutical composition adapted for implantation into a human or animal body to provide a constant, uniform drug release rate over a time interval of several months or years, said composition being substantially free of peroxide, acetic acid and metal salts of carboxylic acids and consisting essentially of a homogeneous mixture of: (a) 85-95 parts by weight of a LTV linear dimethylpolysiloxane resin containing 0.05-0.5 molar percent of methylvinylsiloxane units, having a molecular weight of 20,000-50,000 and containing an average of 1.58-2.02 monovalent hydrocarbon residues per silicone atom; (b) correspondingly 15-5 parts by weight of a crosslinking composition consisting essentially of a dimethylpolysiloxane crosslinking agent substantially free of methylvinylsiloxane units, having a molecular weight of 500-1000 and containing 1-3 Si--H bonds per molecule; (c) a catalytic amount of a noble-metal based crosslinking catalyst; and (d) a pharmaceutically active amount of a nonionic, lipophilic drug dissolved or uniformly suspended in said composition.
Claim 2
Dependent Claim
152 words
A nontoxic pharmaceutical composition adapted for implantation into a human or animal body to provide a constant, uniform drug release rate over a time interval of several months or years, said composition being substantially free of peroxide, acetic acid and metal salts of carboxylic acids and consisting essentially of a homogeneous mixture of: (a) 85-95 parts by weight of a LTV linear dimethylpolysiloxane resin containing 0.05-0.5 molar percent of methylvinylsiloxane units, having a molecular weight of 20,000-50,000 and containing an average of 1.58-2.02 monovalent hydrocarbon residues per silicone atom; (b) correspondingly 15-5 parts by weight of a crosslinking composition consisting essentially of a dimethylpolysiloxane crosslinking agent substantially free of methylvinylsiloxane units, having a molecular weight of 500-1000 and containing 1-3 Si--H bonds per molecule; (c) a catalytic amount of a noble-metal based crosslinking catalyst; and (d) a pharmaceutically active amount of a nonionic, lipophilic drug dissolved or uniformly suspended in said composition.
Claim 3
Dependent Claim
23 words
A composition according to claim 1, wherein said drug is selected from the group consisting of hormones, prostaglandins, vitamins, antibiotics, contraceptives and spermicides.
Claim 4
Dependent Claim
23 words
A composition according to claim 2, comprising 89-91% by weight of component (a) and correspondingly 11-9% by weight of said crosslinking agent (b).
Claim 5
Dependent Claim
47 words
A composition according to claim 2, wherein component (b) consists essentially of 5-10 parts by weight of said crosslinking agent and 5-10 parts by weight of a dimethylpolysiloxane resin having a molecular weight of 10,000-40,000 and having 0.2-1.5 molar percent methylvinylsiloxane units as a auxiliary crosslinking agent.
Claim 6
Dependent Claim
28 words
A composition according to claim 4, comprising 85-89% by weight of component (a); 5-6% by weight of said crosslinking agent; and 5-10% by weight of said dimethylpolysiloxane resin.
Claim 7
Dependent Claim
15 words
A composition according to claim 2, wherein the noble metal-based crosslinking catalyst is hexachloroplatinic acid.
Claim 8
Dependent Claim
27 words
A shaped object having a Shore A hardness of 45-70 prepared by vulcanizing an air-bubble free composition according to claim 2 at 40°-120° C. for 1-6 hours.
Claim 9
Dependent Claim
27 words
A shaped object according to claim 7, wherein said composition comprises 89-91% by weight of component (a) and correspondingly 11-9% by weight of said crosslinking agent (b).
Claim 10
Dependent Claim
50 words
A shaped object according to claim 7, wherein said composition comprises 85-89% by weight of component (a); 5-6% by weight of said crosslinking agent; and 5-10% by weight of a dimethylpolysiloxane resin having a molecular weight of 10,000--10,000 and having 0.2-1.5 molar percent methylvinylsiloxane units as an auxiliary crosslinking agent.
Claim 11
Dependent Claim
7 words
A vulcanized composition according to claim 2.
Claim 12
Dependent Claim
7 words
A vulcanized composition according to claim 3.
Claim 13
Dependent Claim
7 words
A vulcanized composition according to claim 4.
Claim 14
Dependent Claim
7 words
A vulcanized composition according to claim 5.
Claim 15
Dependent Claim
48 words
In a process for preparing a nontoxic pharmaceutical composition having a constant drug release rate over a long period of time and containing a pharmaceutically active amount of a nonionic, lipophilic drug and a pharmaceutically acceptable carrier, the improvement which comprises employing the composition according to claim 1.
Claim 16
Dependent Claim
23 words
A process according to claim 14, wherein said drug is selected from the group consisting of hormones, prostaglandins, vitamins, antibiotics, contraceptives and spermacides.
Claim 17
Dependent Claim
13 words
A process according to claim 15, wherein said crosslinking catalyst is hexachloroplatinic acid.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-10-28 | 1984-04-28 | 1984-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-10-28 | 1988-04-28 | 1988-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-10-28 | 1992-04-28 | 1992-10-28 | $7700.00 | Window Closed / Lapsed |