The effect of gastric prandial conditions on in vitro drug release from oral, locally acting, colon-targeted, mesalamine formulations has not been previously evaluated. In vitro dissolution of four mesalamine formulations were investigated using a USP II paddle apparatus. Fed gastric conditions were simulated under three consecutive phases of milk/buffer at different ratios to simulate changes in physicochemical, gastric composition during food digestion. Drug release was not observed from enteric coated preparations in the fasted state. Under simulative postprandial gastric conditions, however, drug release from Apriso® extended release (ER) capsules was 19 ± 4.7 %. As for Lialda® delayed release (DR) tablets, following two hours of exposure to simulative ileo-colonic media comprising bicarbonate buffer, drug release in the fed and fasted states was 55.7 ± 22.4 % and 12.4 ± 6.4 %, respectively. Significant differences in in vitro dissolution profiles were not observed between fasted and fed conditions for Pentasa® ER capsules and Asacol® HD DR tablets. Published pharmacokinetic data for Apriso and Lialda show higher systemic absorption of mesalamine in fed compared to fasted individuals. Our in vitro data is consistent with these pharmacokinetic findings since fed conditions may give rise to a higher extent of proximal drug release and therefore greater systemic absorption. Furthermore, extent of systemic exposure to mesalamine from Pentasa and Asacol was found not to be affected by food intake. In vitro dissolution studies simulating the gastric prandial state can possibly predict the impact of food on drug release from delayed and sustained release, locally acting formulations.
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