Ion-pair formation as a strategy to enhance topical delivery of salicylic acid

An in-vitro study was carried out to determine the possibility of improving the efficiency of transdermal delivery of salicylate through human epiderm is by ion-pair formers (alkyl-amines and quaternary ammonium ions). Further , the relationship between the physicochemical propel ties of the counter-i ons and salicylate flux was examined. It was found that flux can be related to the conductivity associated with t he penetrant solution, molecular size of the counter-ion and lipophilicity expressed as either octanol/water partition coefficient of the ion pairs or the carbon chain-length of the counter-ions. Equations have been developed to predict salicylate Aux from these physicoc hemical parameters.