[Drug transport through artificial lipoid membranes. 21. Ion pair transport with alkyl salicylic acids].

Using hexylsalicylic acid it was demonstrated that alkylated derivatives of salicylic acid are able to increase partition and transport of ionized basic drugs across lipophilic membranes. The influence of different donor concentrations on the relation of transport was studied by means of pholedrine in combination with hexylsalicylic acid. In order to explain the mechanism of the ion-pair-transport experiments were carried out which show beside the mentioned increase of transport the occurrence of a countertransport of protons and lithium-ions, respectively. The lipophilic counterion hexylsalicylate acts inside of this mechanism as a carrier for the ionized drugs.