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US5597584A
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Method of controlling release of an active or drug from a silicone rubber matrix
Assignee: Dow Silicones Corp
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Filing: 1995-08-02
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Granted: 1997-01-28
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Expires: 2015-08-02
Abstract
Abstract The instant invention pertains to a method of controlling release of active agents or drugs from a silicone rubber matrix by controlling the degree of crosslinking in the silicone rubber matrix. The silicone rubber matrixes of the instant invention are produced from liquid silicone rubbers comprised of (A) a polyorganosiloxane containing at least two alkenyl radicals per molecule; (B) an organohydrogensiloxane containing at least two silicon-bonded hydrogen atoms per molecule; and (C) a hydrosilylation catalyst in an amount sufficient to promote curing of said composition.
Inventors
- 👤 Padmanabh P. Bhatt
- 👤 Victor A. Raul
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 08:20
CPC Classifications
A; A61; A61K; A61K9/00; A61K9/20; A61K9/2004; A61K9/2022; A61K9/2031; A61K9/2036
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
138 words
A method of controlling release of a drug from a silicone rubber matrix having a crosslink density comprising (A) loading a drug into a liquid silicone rubber comprising (a) a polydiorganosiloxane containing at least two alkenyl radicals per molecule; (b) a organohydrogensiloxane containing at least two silicon-bonded hydrogen atoms per molecule; and (c) a hydrosilylating catalyst in an amount sufficient to promote curing of the liquid silicone rubber; wherein the organohydrogensiloxane (b) is present in an amount sufficient to provide a molar ratio of alkenyl radicals in polyorganosiloxane (a) to silicon-bonded hydrogen atoms in organohydrogensiloxane (b) of from 0.5:1 to 20:1; (B) curing the liquid silicone rubber while being molded into a shape; (C) thereafter releasing the drug at a rate; wherein the rate of release is controlled by changing the crosslink density of the silicone rubber matrix.
Claim 2
Independent Claim
138 words
A method of controlling release of a drug from a silicone rubber matrix having a crosslink density comprising (A) loading a drug into a liquid silicone rubber comprising (a) a polydiorganosiloxane containing at least two alkenyl radicals per molecule; (b) a organohydrogensiloxane containing at least two silicon-bonded hydrogen atoms per molecule; and (c) a hydrosilylating catalyst in an amount sufficient to promote curing of the liquid silicone rubber; wherein the organohydrogensiloxane (b) is present in an amount sufficient to provide a molar ratio of alkenyl radicals in polyorganosiloxane (a) to silicon-bonded hydrogen atoms in organohydrogensiloxane (b) of from 0.5:1 to 20:1; (B) curing the liquid silicone rubber while being molded into a shape; (C) thereafter releasing the drug at a rate; wherein the rate of release is controlled by changing the crosslink density of the silicone rubber matrix.
Claim 3
Dependent Claim
70 words
A method as claimed in claim 1 wherein the polyorganosiloxane (A) is selected from polyorganosiloxanes having the formula ##STR3## where each R 1 is individually selected from the group consisting of monovalent hydrocarbon radicals, monovalent halohydrocarbon radicals and an alkenyl radical with the proviso that at least two R 1 groups are alkenyl radicals; and n represents a degree of polymerization equivalent to a viscosity of at least 100 mPa.s.
Claim 4
Dependent Claim
59 words
A method as claimed in claim 1 wherein the polyorganosiloxane is selected from polyorganosiloxanes having the formula ##STR4## where each R 2 is individually selected from the group consisting of monovalent hydrocarbon radicals and monovalent halohydrocarbon radicals; R 3 represents an alkenyl radical; and n represents a degree of polymerization equivalent to a viscosity of at least 100 mPa.s.
Claim 5
Dependent Claim
14 words
A method as claimed in claim 1 wherein polyorganosiloxane (A) is a dimethylvinylsiloxy-terminated polydimethylsiloxane.
Claim 6
Dependent Claim
22 words
A method as claimed in claim 1 wherein polyorganosiloxane (A) is a mixture of a dimethylvinylsiloxy-terminated polydimethylsiloxane and a dimethylvinylsiloxane-terminated methylvinyl dimethylpolysiloxane.
Claim 7
Dependent Claim
21 words
A method as claimed in claim 1 wherein polyorganosiloxane (A) has a viscosity of 100 to 1,000,000 mPa.s at 25° C.
Claim 8
Dependent Claim
21 words
A method as claimed in claim 1 wherein organohydrogensiloxane (B) has a viscosity of 3 to 10,000 mPa.s at 25° C.
Claim 9
Dependent Claim
19 words
A method as claimed in claim 1 wherein hydrosilylation catalyst (C) is a platinum metal deposited on a support.
Claim 10
Dependent Claim
16 words
A method as claimed in claim 1 wherein the hydrosilylation catalyst (C) is a platinum compound.
Claim 11
Dependent Claim
16 words
A method as claimed in claim 1 wherein the hydrosilylation catalyst (C) is a platinum complex.
Claim 12
Dependent Claim
16 words
A method as claimed in claim 1 wherein the liquid silicone rubber further comprises a filler.
Claim 13
Dependent Claim
17 words
A method as claimed in claim 1 wherein the liquid silicone rubber further comprises a catalyst inhibitor.
Claim 14
Dependent Claim
17 words
A method as claimed in claim 1 wherein the liquid silicone rubber further comprises a release additive.
Claim 15
Dependent Claim
30 words
A method as claimed in claim 13 wherein the release additive is selected from the group consisting of ethylene glycol, glycerol, polyethylene glycols, polysorbate 80, sodium chloride and sodium alginate.
Claim 16
Dependent Claim
16 words
A method as claimed in claim 1 wherein the drug is soluble in an aqueous medium.
Claim 17
Independent Claim
147 words
A method of controlling release of a drug from a silicone rubber matrix having a crosslink density comprising (A) curing a liquid silicone rubber while being molded into a shape wherein said liquid silicone rubber comprises (a) a polydiorganosiloxane containing at least two alkenyl radicals per molecule; (b) a organohydrogensiloxane containing at least two silicon-bonded hydrogen atoms per molecule; and (c) a hydrosilylating catalyst in an amount sufficient to promote curing of the liquid silicone rubber; wherein the organohydrogensiloxane (b) is present in an amount sufficient to provide a molar ratio of alkenyl radicals in polyorganosiloxane (a) to silicon-bonded hydrogen atoms in organohydrogensiloxane (b) of from 0.5:1 to 20:1; (B) loading a drug into the cured liquid silicone rubber; (C) thereafter releasing the drug at a rate from the matrix; wherein the rate of release is controlled by changing the crosslink density of the silicone rubber matrix.
Claim 18
Independent Claim
147 words
A method of controlling release of a drug from a silicone rubber matrix having a crosslink density comprising (A) curing a liquid silicone rubber while being molded into a shape wherein said liquid silicone rubber comprises (a) a polydiorganosiloxane containing at least two alkenyl radicals per molecule; (b) a organohydrogensiloxane containing at least two silicon-bonded hydrogen atoms per molecule; and (c) a hydrosilylating catalyst in an amount sufficient to promote curing of the liquid silicone rubber; wherein the organohydrogensiloxane (b) is present in an amount sufficient to provide a molar ratio of alkenyl radicals in polyorganosiloxane (a) to silicon-bonded hydrogen atoms in organohydrogensiloxane (b) of from 0.5:1 to 20:1; (B) loading a drug into the cured liquid silicone rubber; (C) thereafter releasing the drug at a rate from the matrix; wherein the rate of release is controlled by changing the crosslink density of the silicone rubber matrix.
Claim 19
Dependent Claim
70 words
A method as claimed in claim 16 wherein the polyorganosiloxane (a) is selected from polyorganosiloxanes having the formula ##STR5## where each R 1 is individually selected from the group consisting of monovalent hydrocarbon radicals, monovalent halohydrocarbon radicals and an alkenyl radical with the proviso that at least two R 1 groups are alkenyl radicals; and n represents a degree of polymerization equivalent to a viscosity of at least 100 mPa.s.
Claim 20
Dependent Claim
14 words
A method as claimed in claim 16 wherein polyorganosiloxane (A) is a dimethylvinylsiloxy-terminated polydimethylsiloxane.
Claim 21
Dependent Claim
22 words
A method as claimed in claim 16 wherein polyorganosiloxane (a) is a mixture of a dimethylvinylsiloxy-terminated polydimethylsiloxane and a dimethylvinylsiloxane-terminated methylvinyl dimethylpolysiloxane.
Claim 22
Dependent Claim
32 words
A method as claimed in claim 16 wherein hydrosilylation catalyst (c) is selected from the group consisting of a platinum metal deposited on a support, a platinum compound, and a platinum complex.
Claim 23
Dependent Claim
16 words
A method as claimed in claim 16 wherein the liquid silicone rubber further comprises a filler.
Claim 24
Dependent Claim
17 words
A method as claimed in claim 16 wherein the liquid silicone rubber further comprises a catalyst inhibitor.
Claim 25
Dependent Claim
17 words
A method as claimed in claim 14 wherein the liquid silicone rubber further comprises a release additive.
Claim 26
Dependent Claim
30 words
A method as claimed in claim 23 wherein the release additive is selected from the group consisting of ethylene glycol, glycerol, polyethylene glycols, polysorbate 80, sodium chloride and sodium alginate.
Claim 27
Dependent Claim
16 words
A method as claimed in claim 16 wherein the drug is soluble in an aqueous medium.
References Cited (Backward Citations)
US4814184A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-01-28 | 2000-07-29 | 2001-01-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-01-28 | 2004-07-29 | 2005-01-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-01-28 | 2008-07-29 | 2009-01-28 | $7700.00 | Window Closed / Lapsed |