Sensitive and selective extractive spectrophotometric method for the Determination of hydroxyzine dihydrochloride in pharmaceuticals

Hydroxyzine dihydrochloride (HDH), a piperazine H-1-receptor antagonist and antihistamine, is a rapid acting anxiolytic used principally as an anti-emetic. A sensitive, selective, and precise and accurate spectrophotometric method based on the formation of an ion-pair with orange II (ORG II) as ion-pair complexing agent was developed and validated for the determination of HDH in pharmaceuticals. The chloroform-extractable ion-pair complex exhibited an absorption maximum at 480 nm. Optimization of different experimental conditions is described. Beer's law is obeyed in the range of 1.5-15 mu g mL(-1) with an apparent molar absorptivity value of 2.07 x 10(4) L mol(-1) cm(-1) and Sandell's sensitivity value of 0.0216 mu g cm(-2). The limit of detection (LOD) and limit of quantification (LOQ) are 0.14 and 0.41 mu g mL(-1), respectively. A Job's plot of absorbance versus molar ratio of HDH to ORG II indicated (1:2) stoichiometric ratio. Within-and between-day relative standard deviations at three different concentration levels were < 3%. The developed method was successfully applied to commercial tablets. The results obtained were in good agreement with those obtained using the official method. No interference was encountered from co-formulated substances. Recoveries were 96-109 %