Spectrophotometric determination of meclozine HCl and papaverine HCl in their pharmaceutical formulations

A simple, accurate and highly sensitive spectrophotometric method is proposed for the rapid determination of meclozine and papaverine hydrochlorides using chromotrope 2B (C2B) and chromotrope 2R (C2R). The method consists of extracting the formed ion-associates into chloroform in the case of meclozine HCl and into methylene chloride in case of papaverine HCl. The ion-associates exhibit absorption maxima at 536 and 524 nm for C2B and C2R with meclozine HCl and at 540 and 528 nm with papaverine HCl, respectively. Meclozine can be determined up to 4.0 and 2.6 mg ml −1, using C2B and C2R, respectively, while papaverine can be determined up to 1.68 and 1.37 mg ml −1, respectively. The effect of acidity, reagent concentration, time, solvent and stoichiometric ratio of the ion-associates were studied. The molar absorptivity and Sandell sensitivity of the reaction products were calculated. The method was applied to the determination of the drugs in their pure state or pharmaceutical preparations with mean recovery values of 99.63–100.80 and 99.75–100.08% and coefficient of variation 0.945–2.210 and 1.020–1.268 for meclozine HCl and papaverine HCl, respectively.