Aggregation of antihistamines in aqueous solution: micellar properties of some diphenylmethane derivatives

Abstract

Abstract The micellar properties of the antihistamine drugs, diphenhydramine hydrochloride, bromodiphenhydramine hydrochloride, chlorcyclizine hydrochloride and diphenylpyraline hydrochloride, have been studied in aqueous solution. The zeta potentials of the micelles were calculated from their electrophoretic mobilities as determined by a dye-tracer technique. Estimates of the degree of ionization of the micelles using a combination of conductivity and electrophoresis data were in reasonable agreement with values previously determined by light scattering. The extent of micellar hydration has been calculated from viscosity data. The hydrophobic and electrical contributions to the free energy of micellization have been calculated and related to the chemical structure.