Determination of meclizine hydrochloride by ion-pair extraction with methyl orange.

A method, based on ion-pair extraction, is described for the quantification of meclizine hydrochloride in various pharmaceutical dosage forms, for content uniformity determination, and for concentration monitoring in dissolution and bioavailability studies. Methyl orange, dissolved in pH 2.8 MacIlvaine buffer, gave excellent recovery of meclizine after its isolation from aqueous solutions of gelatin, urine, and blood serum. The chloroform-extracted molecular species appeared to be a 1:1 ion-pair. Beer's law was obeyed for a wide concentration range. Because the extracted species seemed well defined and stable and since a surface or an interphase adsorption phenomenon was not a problem, the reported method is considered sensitive, accurate, precise, rapid, and simple.