Intestinal absorption of a new anticholinergic agent, timepidium bromide. II. Enhancement of absorption.

Abstract

Enhancement of absorption of a quaternary anticholinergic agent, timepidium bromide (TB), was studied in vivo and in situ in rats. Intraduodenally administered citric acid markedly increased the amount of TB absorbed, but orally administered citric acid did only slightly. The difference in absorption of TB between oral and duodenal administration of citric acid was assumed to be due to the fact that citric acid delayed gastric emptying. It was found that the absorption of TB from in situ intestinal loop varied with drug concentration, the greater the concentration the greater the absorption. In the presence of high concentrated solution of tertiary amine of TB, diphemanil methylsulfate or prifinium bromide, which are structural analogues of TB, the absorption of TB was markedly enhanced. This increased absorption of TB was unrelated to the activity of the additives as an anticholinergic agent.