An in vitro model for drug absorption studies

The transfer of salicylic acid and of three sulphonamides from an aqueous phase of pH 2 or pH 5 through an intervening organic phase to an aqueous phase of pH 7.4 has been studied using a rotating cell. The manner of operation of the cell promotes rapid drug transfer without vortexing or emulsification of the phases. The rates of transfer of the drugs showed the anticipated pH dependance.