1999 年 59 巻 4 号 p. 156-162
Since the lipophilic basic compound S-2150 displays markedly low solubility in the pH range above 4.4, its dissolution rate and permeability across the gastrointestinal (GI) membrane are considered to vary depending on the pH and luminal fluid volume along the GI tract. We used a gastric emptying (GE)-convolution method to simulate the in vivo dissolution profiles of enteric-coated S-2150 granules after administration to dogs. In this method, the GE rate of the granules was calculated from the cumulative absorption after the administration of acetaminophen enteric-coated granules. The weighing function was the in vitro dissolution profile obtained in a pH 6.0 test solution with the assumption that the dissolution would terminate after a granule residence time (20 min) at the effective release/absorption site in the GI tract. The simulated in vivo dissolution profiles agreed well with the absorption profiles, and a good in vitro / in vivo correlation (IVIVC) was achieved. The present procedure is a straightforward way of predicting the bioavailability of various multiple-unit type enteric-coated formulations. It is useful for designing and/or optimizing evaluation methods and also to obtain a good IVIVC.
