Gastric Acidity-Dependent Bioavailability of Commercial Sustained Release Preparations of Indomethacin, Evaluated by Gastric Acidity-Controlled Beagle Dogs

The relationship between gastric acidity and the bioavailability of two kinds of sustained-release indomethacin (IM) formulations was investigated in gastric acidity-controlled beagle dogs, and compared with that of rapid-release IM formulations.All test dosage forms were more rapidly dissolved in simulated intestinal fluid than in simulated gastric fluid.Gastric acidity did not affect the bioavailability of IM from the rapid-release formulation. However, the bioavailability of IM from the two kinds of sustained-release formulations were markedly influenced by gastric acidity. The rates of IM bioavailability from both of the sustained-release formulations were faster under low acidity conditions than under high acidity conditions (p