Weiss, G. and Knoch, A. and Laicher, A. and Stanislaus, F. and Daniels, R. (1995) Simple coacervation of hydroxypropyl methylcellulose phthalate (HPMCP) II. Microencapsulation of ibuprofen. INTERNATIONAL JOURNAL OF PHARMACEUTICS, 124 (1). pp. 97-105. ISSN 0378-5173, 1873-3476
Full text not available from this repository.Abstract
Microencapsulation with hydroxypropyl methylcellulose phthalate (HPMCP) through simple coacervation by the addition of 20% (w/w) sodium sulphate solution was investigated on the basis of the temperature-dependent coacervate formation of the polymer. The nonsteroidal antirheumatic drug ibuprofen was used as model substance. This paper describes the microencapsulation process and the resulting microcapsules. Furthermore, the influence of docusate sodium present during encapsulation was investigated with respect to the phase separation behaviour of HPMCP and the wall characteristics of the microcapsules. Simple coacervation of HPMCP is a suitable method for the microencapsulation of ibuprofen. The coacervate enveloped the suspended drug which had no effect upon the phase separation of the polymer owing to the low solubility of ibuprofen in the HPMCP solution, The microencapsulation process was controlled by temperature increase: additional coacervate for the coating of the drug crystals was formed and the resulting coacervate shells were subsequently prehardened by jelling. This enabled the recovery and isolation of the microcapsules to be performed. The coating of the drug crystals occurred as twins and multiples when microencapsulation was performed without surfactant; SEM micrographs demonstrated the high shell quality of the microcapsules and polymer yield calculations showed the almost complete utilization of the coacervate for enveloping the drug crystals in surfactant-free systems. Small amounts of docusate sodium present during microencapsulation resulted in a more individual encapsulation of the ibuprofen crystals; however, coating by the coacervate was incomplete and the microcapsules showed clod-like polymer shell deficiencies. As a consequence, an increased release rate of ibuprofen at pH 4.0 was observed compared to microcapsules prepared without using surfactant. Since docusate sodium had no effect upon the phase separation behaviour of HPMCP under the conditions used for microencapsulation, the incomplete polymer coating was attributed to competition between surfactant and coacervate for the solid/liquid interface.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | SURFACTANTS; GELATIN; ACID; MICROENCAPSULATION; CONSERVATION; HYDROXYPROPYL METHYLCELLULOSE PHTHALATE; IBUPROFEN; SURFACTANT; TASTE MASKING; ENTERIC |
| Subjects: | 600 Technology > 600 Technology (Applied sciences) 600 Technology > 615 Pharmacy |
| Divisions: | Chemistry and Pharmacy > Institute of Pharmacy > Pharmaceutical Technology (Prof. Göpferich) |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 16 Jan 2024 06:18 |
| Last Modified: | 16 Jan 2024 06:18 |
| URI: | https://pred.uni-regensburg.de/id/eprint/52315 |
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