US4518547A
Expired / Lapsed
US
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Microencapsulation process
Assignee: The University of Texas System
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Filing: 1983-09-15
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Granted: 1985-05-21
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Expires: 2003-09-15
Abstract
Abstract Nylon coated microcapsules containing hydrophilic solvent-soluble anionic, cationic or quaternary drug salts were prepared by interfacial polycondensation techniques. In a first stage, the drug substance to be encapsulated is dissolved in an aqueous phase. Examples of drugs encapsulated are morphine sulfate, diphenhydramine hydrochloride, and methantheline bromide. Next the aqueous drug solution is dispersed in an organic phase. In a second stage complementary polycondensation reactants each in an organic phase are added separately, either sequentially or simultaneously, to the dispersion prepared in the first stage. Microcapsules of nylon form around the hydrophilic solvent soluble core drug substance.
Inventors
- 👤 George W. Cuff
- 👤 James W. McGinity
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 08:37
CPC Classifications
A; A61; A61K; A61K9/00; A61K9/48; A61K9/50; B; B01; B01J; B01J13/00; B01J13/02; B01J13/06; B01J13/14; B01J13/16
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
133 words
A process for the encapsulation of a hydrophilic core material in a membrane formed by interfacial polycondensation, the process comprising: in a first step, dispersing in a first continuous hydrophobic phase a hydrophilic phase comprising in solution the hydrophilic material to be encapsulated and a hydrophilic solvent or water; and then in a second stage, adding separately to the dispersion either sequentially or simultaneously, each of two complementary polycondensation monomer reactants: the first polycondensation monomer reactant comprising a hydrophobic solvent-soluble reagent; the second polycondensation monomer reactant comprising a hydrophilic solvent-soluble reagent dispersed in a second continuous hydrophobic phase; allowing the polycondensation monomers to react, the reaction effective to cause interfacial polymerization of a membrane encapsulating the hydrophilic phase containing the hydrophilic core material; and separating the encapsulated material from the continuous hydrophobic phase.
Claim 2
Dependent Claim
133 words
A process for the encapsulation of a hydrophilic core material in a membrane formed by interfacial polycondensation, the process comprising: in a first step, dispersing in a first continuous hydrophobic phase a hydrophilic phase comprising in solution the hydrophilic material to be encapsulated and a hydrophilic solvent or water; and then in a second stage, adding separately to the dispersion either sequentially or simultaneously, each of two complementary polycondensation monomer reactants: the first polycondensation monomer reactant comprising a hydrophobic solvent-soluble reagent; the second polycondensation monomer reactant comprising a hydrophilic solvent-soluble reagent dispersed in a second continuous hydrophobic phase; allowing the polycondensation monomers to react, the reaction effective to cause interfacial polymerization of a membrane encapsulating the hydrophilic phase containing the hydrophilic core material; and separating the encapsulated material from the continuous hydrophobic phase.
Claim 3
Dependent Claim
22 words
The process according to claim 1 wherein the hydrophilic core comprises water soluble salts of anionic, cationic, quaternary, amphoteric or nonionic compounds.
Claim 4
Dependent Claim
21 words
The process according to claim 1 wherein the first or second continuous hydrophobic phase is a solution of cyclohexane and chloroform.
Claim 5
Dependent Claim
29 words
The process according to claim 1 wherein the first polycondensation monomer is selected from the group consisting of multifunctional acid halides, diacids, diisocyanates, multifunctional sulfonyl halides, and mixtures thereof.
Claim 6
Dependent Claim
16 words
The process according to claim 1 wherein the first polycondensation monomer is a multifunctional acid halide.
Claim 7
Dependent Claim
14 words
The process according to claim 5 wherein the multifunctional acid halide is sebacyl chloride.
Claim 8
Dependent Claim
34 words
The process according to claim 1 wherein the second polycondensation monomer reactant is selected from the group consisting of polyfunctional amines, polyols, diamines, and diols, and mixtures thereof dispersed in a hydrophobic continuous phase.
Claim 9
Dependent Claim
15 words
The process according to claim 1 wherein the second polycondensation monomer reactant is a diamine.
Claim 10
Dependent Claim
11 words
The process according to claim 8 wherein the diamine is hexamethylenediamine.
Claim 11
Dependent Claim
22 words
The process according to claim 1 wherein both the first and second polycondensation monomer reactants are added simultaneously to the first dispersion.
References Cited (Backward Citations)
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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) | 1988-05-20 | 1988-11-19 | 1989-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-05-20 | 1992-11-19 | 1993-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-05-20 | 1996-11-19 | 1997-05-21 | $7700.00 | Window Closed / Lapsed |