The present study examines the lipophilic behaviour of trandolapril by partitioning the drug in a chloroform-water system at room temperature. The aqueous vehicles investigated are glycerolwater, propylene glycol-water and polysorbate 80-water systems. The results show that both the binary combinations and the surfactant solution decreased the lipophilicity of trandolapril. The order of decrease is: polysorbate 80__ampersandsigngt; propylene glycol__ampersandsigngt; glycerol. The findings suggest that none of the vehicles investigated, has the potential of enhancing the vehicle-skin partition coefficient and therefore might not be considered as potential dermal enhancers for trandolapril.