Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
2485526 | Journal of Pharmaceutical Sciences | 2008 | 15 Pages |
Abstract
Enteric coatings that deliver drugs to specific regions of the small intestine were examined. Hypromellose acetate succinate (HPMCAS) with different values of succinoyl group contents was used. Decreasing the succinoyl group content resulted in an increase in the pH at which HPMCAS started to dissolve. Drugâcontaining granules with or without enteric coating were prepared and their in vitro dissolution in a simulated intestinal fluid of pH 6.8 was examined. Granules coated with HPMCAS having the succinoyl group content of 6.2% showed a lag time of about 30Â min, although drug release from granules without coating was completed within 20Â min. The time lag and dissolution rate were extended and reduced, respectively, as the succinoyl group content was decreased. Rat experiments indicated that entericâcoated granules disintegrated and the bulk of the drugs was immediately released when the granules reached a specific site of the small intestine where the pH corresponded to the pH at which the enteric coating agent started to dissolve. Similar results were observed in monkey experiments. It was suggested that HPMCAS with the succinoyl group content of about 5% was suitable as an enteric coating agent for delivering drugs to the middleâtoâlower region of the small intestine.
Keywords
Related Topics
Health Sciences
Pharmacology, Toxicology and Pharmaceutical Science
Drug Discovery
Authors
Fumié K. Tanno, Shinji Sakuma, Yoshie Masaoka, Makoto Kataoka, Toshio Kozaki, Ryosei Kamaguchi, Yutaka Ikeda, Hiroyasu Kokubo, Shinji Yamashita,