Effect of adjuvants on the rectal absorption and lymphatic uptake of pepleomycin in rats.

The rectal absorption of pepleomycin sulfate (PEPS) in rats was increased significantly by the coadministration with each of diclofenac (DC), sodium 5-methoxysalicylate (5-MSA) and phenylalanine enamine of ethylacetoacetate (Enamine). 5-MSA increased the lymphatic uptake of PEPS after rectal administration while DC and Enamine did not. The mechanism behind the enhancing action of 5-MSA on the lymphatic uptake of PEPS may be due to the suppressing action of 5-MSA on the vascular permeability to PEPS. DC increased the vascular permeability to PEPS but Enamine did not affect it. Findings obtained in this study may indicate that adjuvant used acts independently at the rectal mucosal membrane and at the vascular membrane for membrane for membrane permeability to PEPS.