Studies on absorption and excretion of drugs. IX. Relation between chemical structure and absorption rate. (I). Effects of the number and the position of OH-groups on the intestinal absorption rate of benzyl derivatives.

Abstract

The aqueous solutions of 24 benzoyl derivatives were perfused through the samll intestine of anesthetized rats. The absorption rate coefficient calculated from the slope of the straight line which was obtained from the logarithmic plots of the residual ratio vs. time was used for comparison of the intestinal absorption rates of these foreign organic compounds. In each series (benzoic acid-, benzaldehyde-, methyl benzoate-series), the absorption rate decreased as the number of hydroxyl groups increased. When comparing the monohydroxyl derivatives in each series, the o-isomer was absorbed faster than m- and p-isomers, but this was not true of methoxyl derivatives. From these facts, it is suggested that Danielli's model may be applied to the intestinal absorption of foreign organic compounds.