EP0130162A2
Expired / Lapsed
EP
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Small particle formation and encapsulation
Assignee: Ohio State University Research Foundation
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Filing: 1984-06-14
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Granted: —
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Expires: 2004-06-14
Abstract
Abstract Process for the formation and the simultaneous encapsulation of small particles of a compound from solution.
Inventors
- 👤 Sylvan Gerald Frank
- 👤 Arne Folke Brodin
- 👤 Chih-Ming James Chen
- 👤 Siriporn Panthuvanich
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 15:17
CPC Classifications
A; A61; A61K; A61K9/00; A61K9/48; A61K9/50; A61K9/5005; A61K9/5021; A61K9/5036; A61K9/5042; C; C05; C05F; C05F7/00; A61K9/5026; A61K9/5047; A61K9/5052; A61K9/5057; A61K9/5089; B; B01; B01J; B01J13/00; B01J13/02; B01J13/06; B01J13/10
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
137 words
1 . A process for encapsulating a weakly acidic organic compound whose solubility in water is greater at a first pH than at a second pH which process comprises: (a) dissolving said compound in water in the presence of sufficient base to raise the pH to said first pH and at least 2 pH units above the pKa of the compound, together with an encapsulating material and an electrolyte which is effective, but present in an amount just insufficient to cause coacervation of the encapsulating material without interacting with it; (b) stirring and titrating the solution with a titrant effective to reduce the pH of said solution to said second pH to cause the concurrent precipitation of the compound as small particles and formation of a coacervate of the encapsulating material; and (c) gelling the encapsulating material.
Claim 2
Dependent Claim
137 words
1 . A process for encapsulating a weakly acidic organic compound whose solubility in water is greater at a first pH than at a second pH which process comprises: (a) dissolving said compound in water in the presence of sufficient base to raise the pH to said first pH and at least 2 pH units above the pKa of the compound, together with an encapsulating material and an electrolyte which is effective, but present in an amount just insufficient to cause coacervation of the encapsulating material without interacting with it; (b) stirring and titrating the solution with a titrant effective to reduce the pH of said solution to said second pH to cause the concurrent precipitation of the compound as small particles and formation of a coacervate of the encapsulating material; and (c) gelling the encapsulating material.
Claim 3
Dependent Claim
135 words
A process for encapsulating a weakly basic organic compound whose solubility in water is greater at a first pH than at a second pH which process comprises: (a) dissolving said compound in water in the presence of sufficient acid to lower the pH to said first p H and at least 2 pH units below the pKa of the compound, together with an encapsulating material and an amount of an electrolyte which is effective, but just insufficient to cause coacervation of the encapsulating material without interacting with it; (b) stirring and titrating the solution with a titrant effective to raise the pH of said solution to said second pH to cause the concurrent precipitation of the compound as small particles and formation of a coacervate of the encapsulating material; and (c) gelling the encapsulating material.
Claim 4
Dependent Claim
135 words
A process for encapsulating a weakly basic organic compound whose solubility in water is greater at a first pH than at a second pH which process comprises: (a) dissolving said compound in water in the presence of sufficient acid to lower the pH to said first p H and at least 2 pH units below the pKa of the compound, together with an encapsulating material and an amount of an electrolyte which is effective, but just insufficient to cause coacervation of the encapsulating material without interacting with it; (b) stirring and titrating the solution with a titrant effective to raise the pH of said solution to said second pH to cause the concurrent precipitation of the compound as small particles and formation of a coacervate of the encapsulating material; and (c) gelling the encapsulating material.
Claim 5
Dependent Claim
14 words
A process according to claims 1 or 2 wherein the compound is pharmaceutically active.
Claim 6
Dependent Claim
26 words
A process according to claim 2 wherein the compound is sulfadiazine in sodium sulfate solution containing ethyl alcohol and the encapsulating material is a gelatin solution.
Claim 7
Dependent Claim
14 words
The process according to claim 3 wherein the first pH is an acid pH.
Claim 8
Dependent Claim
17 words
A process according to claim 1 or 2 wherein a wetting agent is used in step a.
Claim 9
Dependent Claim
18 words
A process according to claim 1 or 2 wherein, if needed, the temperature is controlled in step b.
Claim 10
Dependent Claim
33 words
A process according to claim 1, wherein the pharmaceutically active compound is selected from the group consisting of bacampicillin, griseofulvin, indomethacin, sodium sulfadiazine, erythromycin, theophylline, salicylic acid, acetylsalicylic acid, chlorozoxazone, lidocaine and alaproclate.
Claim 11
Dependent Claim
26 words
A process according to claim 1, wherein the encapsulating material is selected from the group consisting of gelatin, methylcellulose, sodium carboxymethylcellulose, cellulose acetate phthalate, and polyvinylpyrrolidone.
Claim 12
Dependent Claim
20 words
A process according to claim 4, wherein the ratio of encapsulating material to wetting agent to electrolyte is about (0.1-6):(0.1-4):(0.1-10):(0.4-48).
References Cited (Backward Citations)
No citation records indexed.
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