US4479911A
Expired / Lapsed
US
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Process for preparation of microspheres and modification of release rate of core material
Assignee: Sandoz Inc
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Filing: 1983-03-08
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Granted: 1984-10-30
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Expires: 2003-03-08
Abstract
Abstract This invention provides for the production of microspheres in an oil-in-water emulsion process using an emulsifier, whereby solvent removal from the oil phase allows for isolation of discrete microspheres, wherein the release rate of a core material is modified by the use of an alkaline agent, e.g. sodium hydroxide, during the preparation of the microspheres.
Inventors
- 👤 Jones W. Fong
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:19
CPC Classifications
B; B01; B01J; B01J13/00; B01J13/02; B01J13/06; B01J13/12; B01J13/125; A; A61; A61K; A61K9/00; A61K9/14; A61K9/16; A61K9/1605; A61K9/1629; A61K9/1641; A61K9/1647; A61K9/1682; A61K9/1694; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2989
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
131 words
In a process for the preparation of microspheres having a particulate core material encapsulated by a polymer coating wherein the polymer is dissolved in a volatile water-immiscible solvent in which the core material is not soluble, adding the core material particles, mixing the resulting dispersion with an aqueous emulsifier solution to form an oil-in-water emulsion, and removing the solvent to form discrete microcapsules, the improvement which comprises adding from about 0.5 to about 20 percent based on the weight of the polymer of a basic inorganic salt, an alkaline buffer solution or an organic amine as an alkaline agent to a sodium oleate, potassium oleate, or polyvinyl alcohol aqueous emulsifier solution for mixing with the dispersion, wherein the alkaline agent modifies the release rate of the core material from the microcapsules.
Claim 2
Dependent Claim
131 words
In a process for the preparation of microspheres having a particulate core material encapsulated by a polymer coating wherein the polymer is dissolved in a volatile water-immiscible solvent in which the core material is not soluble, adding the core material particles, mixing the resulting dispersion with an aqueous emulsifier solution to form an oil-in-water emulsion, and removing the solvent to form discrete microcapsules, the improvement which comprises adding from about 0.5 to about 20 percent based on the weight of the polymer of a basic inorganic salt, an alkaline buffer solution or an organic amine as an alkaline agent to a sodium oleate, potassium oleate, or polyvinyl alcohol aqueous emulsifier solution for mixing with the dispersion, wherein the alkaline agent modifies the release rate of the core material from the microcapsules.
Claim 3
Dependent Claim
16 words
The process according to claim 1 wherein the alkaline agent is sodium hydroxide or potassium hydroxide.
Claim 4
Dependent Claim
13 words
The process according to claim 2 wherein the polymer is a biodegradable polymer.
Claim 5
Dependent Claim
21 words
The process according to claim 3 wherein the biodegradable polymer is polylactic acid, poly(lactic acid/glycolic acid) copolymer, or poly(lactic acid/epsilon-caprolactone) copolymer.
Claim 6
Dependent Claim
14 words
The process according to claim 4 where in the core material is a drug.
Claim 7
Dependent Claim
27 words
The process according to claim 5 wherein the drug is thioridiazine, ketotifen, temazepam, bromocriptine, or a mixture of dihydroergocornine, dihydroergocristine, and dihydroergokryptine, or acid addition salts thereof.
Claim 8
Dependent Claim
20 words
The process according to claim 1 wherein the amount of alkaline agent is from about 0.5 to about 10 percent.
Claim 9
Dependent Claim
125 words
In a process for the preparation of microspheres having a homogeneous mixture of polymer and core material wherein both the polymer and core material are dissolved in a volatile, water immiscible solvent, mixing the polymer-core material-solvent system with an aqueous emulsifier solution to form an oil-in-water emulsion and removing the solvent to form discrete microprills, the improvement which comprises adding from about 0.5 to about 20 percent based on the weight of the polymer of a basic inorganic salt, an alkaline buffer solution or an organic amine as in alkaline agent to a sodium oleate, potassium oleate, or polyvinyl alcohol aqueous emulsifier solution for mixing with the polymer-core material-solvent system, wherein the alkaline agent modifies the release rate of the core material from the microcapsules.
Claim 10
Dependent Claim
125 words
In a process for the preparation of microspheres having a homogeneous mixture of polymer and core material wherein both the polymer and core material are dissolved in a volatile, water immiscible solvent, mixing the polymer-core material-solvent system with an aqueous emulsifier solution to form an oil-in-water emulsion and removing the solvent to form discrete microprills, the improvement which comprises adding from about 0.5 to about 20 percent based on the weight of the polymer of a basic inorganic salt, an alkaline buffer solution or an organic amine as in alkaline agent to a sodium oleate, potassium oleate, or polyvinyl alcohol aqueous emulsifier solution for mixing with the polymer-core material-solvent system, wherein the alkaline agent modifies the release rate of the core material from the microcapsules.
Claim 11
Dependent Claim
16 words
The process according to claim 8 wherein the alkaline agent is sodium hydroxide or potassium hydroxide.
Claim 12
Dependent Claim
13 words
The process according to claim 9 wherein the polymer is a biodegradable polymer.
Claim 13
Dependent Claim
20 words
The process according to claim 10 wherein the biodegradable polymer is polylactic acid, poly(lactic acid/glycolic acid)copolymer, or poly(lactic acid/epsilon-caprolactone) copolymer.
Claim 14
Dependent Claim
14 words
The process according to claim 11 where in the core material is a drug.
Claim 15
Dependent Claim
33 words
The process according to claim 12 wherein the drug is selected from the group consisting of thioridazine, ketotifen, temazepam, bromocriptine, or a mixture of dihydroergocornine, dihydroergocristine, and dihydroergokryptine, or acid addition salts thereof.
Claim 16
Dependent Claim
20 words
The process according to claim 8 wherein the amount of alkaline agent is from about 0.5 to about 10 percent.
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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) | 1987-10-30 | 1988-04-30 | 1988-10-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-10-30 | 1992-04-30 | 1992-10-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-10-30 | 1996-04-30 | 1996-10-30 | $7700.00 | Window Closed / Lapsed |