Sensitive and Selective Extractive Spectrophotometric Method for the Determination of Hydroxyzine Dihydrochloride in Pharmaceuticals

hydroxyzine dihydrochloride (hdh), a piperazine h1-receptor antagonist and antihistamine, is a rapid acting anxiolytic used principally as an antiemetic. 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 μg ml-1 with an apparent molar absorptivity value of 2.07 × 104 l mol-1 cm-1 and sandell's sensitivity value of 0.0216 μg cm-2. the limit of detection (lod) and limit of quantification (loq) are 0.14 and 0.41 μg 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 coformulated substances. recoveries were 96-109 %.