The influence of gastric emptying on plasma concentrations of the analgesic, meptazinol

Abstract

1. The influence of gastric emptying on the rate of absorption and peak plasma concentrations of meptazinol was studied in monkeys by comparison of the plasma concentrations of the drug achieved after intragastric and intraduodenal administration of the compound. Absorption was much more rapid and plasma concentrations were very much higher after intraduodenal than after intragastric dosage. 2. Determination of the 'normal' gastric emptying time in rats and monkeys showed that this was much longer in the monkey than in the rat. In addition, meptazinol was shown to have a pronounced retarding action on gastric emptying in the monkey, an effect which was not apparent in the rat. 3. The significance of these observations in relation to the species difference in oral potency of the drug is discussed.