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Updated: Sep 20, 2026

Preparation and Characterization of Individual and Multi-drug Loaded Physically Entrapped Polymeric Micelles
Published on: August 28, 2015
The effect of polyion complex formation on in vitro/in vivo correlation of hydrophilic matrix tablets
Yasunori Miyazaki1, Shigeru Yakou, Tsuneji Nagai
1Pharmaceutical Department, Tokyo Women's Medical University, Daini Hospital, Nishiogu-2-1-10, Arakawa-ku, Tokyo 116-8567, Japan. myph@dnh.twmu.ac.jp
Abstract:
The aim of this study was to investigate the effects of polyion complex formation on in vivo performance of hydrophilic matrix tablets. Three kinds of controlled release theophylline tablets were prepared by direct compression using carboxymethyldextran (CMD), a mixture of CMD and [2-(diethylamino)ethyl]dextran (EA), and a mixture of dextran sulfate (DS) and EA. According to a conventional dissolution test, in vitro drug release profiles of these tablets were similar to each other. In vivo absorption profiles of theophylline after oral administration to beagle dogs, however, were quite different and were not consistent with in vitro release profiles. Thus, we applied a modified in vitro release test considering destructive forces. An excellent in vitro/in vivo correlation was obtained in the cases of CMD/EA- and DS/EA-tablets. The results suggested that the drug was released constantly in the overall gastrointestinal tract, and even in the colon. Then, hydrophilic matrices were characterized by swelling rate, matrix density and strength in a wet state. DS/EA-tablets showed limited swelling, higher density and a larger value of wet strength than the others. These findings indicated that polyion complex formation in gel layer contributes to prevent over-swelling and strengthen the wetted matrices.
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