The promotion of drug rectal absorption by water absorption.

The promotion of the rectal absorption of antipyrine by sodium taurocholate (TC-Na) or sodium ethylenediaminetetraacetate (EDTA-Na) has been examined by in-situ recirculating perfusion in the rat. These promoters significantly increased water influx, efflux and antipyrine absorption clearance (CLAP). Ouabain treatment significantly reduced the increase in both rectal absorption of drug and water flux. Water absorption dependent on active sodium transport may thus possibly promote the rectal absorption of poorly absorbable drugs.