Titrimetric Assay of Hydroxyzine Dihydrochloride in Pharmaceuticals and Formulations in Non-aqueous Medium

Hydroxyzine, a piperazine H1-receptor antagonists effective in generalized anxiety disorder. Two simple, rapid, reliable, precise and accurate and cost-effective non-aqueous titrimetric procedures have been developed for the determination of hydroxyzine dihydrochloride (HDH) in bulk drug and its pharmaceutical formulations. The methods are based on the titration of the drug in glacial acetic acid in the presence of mercuric acetate with acetous perchloric acid to the visual end point using crystal violet as indicator and to the potentiometric end point. The methods were applicable over the range of 2-20 mg HDH. The procedures were also applied for the determination of HDH in its dosage forms and the results were found to be in a good agreement with those obtained by the reference method. The precision results, expressed by intra-day and interday relative standard deviation values, were satisfactory (RSD ≤ 1.28 %). The accuracy was satisfactory as well (RE ≤ 1.33 %). Excipients used as additives in pharmaceutical formulations did not interfere in the proposed procedures as shown by the recovery study via standard addition technique with percentage recoveries in the range 97.75-101.5 % with a standard deviation of ≤ 1.52 %.