Spectrophotometric Determination of Alprazolam in Pure and Pharmaceutical Forms using Triphenyl Methane Dyes

Three simple and sensitive extractive spectrophotometric methods have been described for the assay of Alprazolam either in pure form or in pharmaceutical formulations. The developed methods involve formation of coloured chloroform extractable ion-pair complexes of the drug with bromothymol blue (BTB), bromophenol blue (BPB) and bromocresol green (BCG) in acidic medium. The extracted complexes showed absorbance maxima at 410, 408 and 405nm with use of the cited reagents, respectively. The stoichiometry of the complex is found to be 1:1 in each case. Beer’s law is obeyed in the concentration ranges 3.0-25, 4.0-30, and 4.5-40μg/ml with BTB, BPB and BCG respectively. The effect of concentration of dye, pH, and interference of excipients have been studied and optimized. The limits of detection and quantification have been determined for three methods. All the three methods have been validated as per the guidelines of ICH. The methods have been applied to the determination of drug in commercial tablets and results of analysis were validated statistically through recovery studies.