Transport of aspirin and its metabolites through human erythrocyte membrane.

The transport of aspirin (ASP) and its metabolites (salicylic acid (SA), salicyluric acid (SAU), gentisic acid (GA) and gentisuric acid (GAU)) through human erythrocyte membrane was investigated. ASP permeated rapidly into the erythrocytes and the concentration dwindled gradually after the maximum concentration was attained almost within one minute. It was suggested that SA is released from the erythrocytes after ASP transported into the erythrocytes is hydrolyzed in them. In both an inward and outward direction, the transport rates of SA and GA were rapid, while those of SAU and GAU were lower by conjugating glycine. It was suggested that GAU remains for a long time in a living body. The rate of transport of GA and GAU were markedly obstructed by the band 3 protein inhibitor 4,4'-diisothiocyanostilbene-2,2'-disulfonate, although the transport rates of SA and SAU were obstructed only slightly. It was suggested that the transport of GA and GAU are mediated through band 3 protein.