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Indexed by:期刊论文

Date of Publication:2008-11-15

Journal:JOURNAL OF APPLIED POLYMER SCIENCE

Included Journals:SCIE、EI、Scopus

Volume:110

Issue:4

Page Number:2488-2497

ISSN No.:0021-8995

Key Words:drug delivery systems; microencapsulation; simulations

Abstract:Spraying and spraying with an electrostatic field (SEF) were employed to prepare alginate microspheres for delivering proteins, especially for intestinal digestive enzymes and cytokines. The encapsulation efficiency (EE) of a model protein [bovine serum albumin (BSA)] at a pH value lower than the isoelectric point was 20% higher than that at a natural pH. Moreover, for the microspheres prepared by SEF, EE improved significantly with increasing electric voltage. The interactions between BSA and the alginate microspheres were identified with Fourier transform infrared spectroscopy. The release profiles in vitro showed a controlled and pH-responsive release manner for the encapsulated BSA. A first-order release equation was postulated and modified to describe the release kinetics with an obviously initial burst release related to the eroded porous matrix. The equation fit the release data well when the pH value and composition of the release media were changed. The analysis of the release kinetics indicated that the drug release rate was in an inverse ratio to the diameter of the microspheres. Increasing the gas flow rate or electric voltage decreased both the mean diameter and size distribution of the microspheres significantly and enhanced the release rate of loaded drugs from alginate microspheres. Sodium dodecyl sulfate /polyacrylamide gel electrophoresis analysis revealed that BSA kept its structural integrity during the encapsulation and release process. (C) 2008 Wiley Periodicals, Inc.