SPECTROPHOTOMETRIC DETERMINATION OF CARISOPRODOL IN PURE AND PHARMACEUTICAL FORMS USING TRIPHENYL METHANE DYES

New simple and sensitive extractive spectrophotometric methods have been developed and described for the determination of carisoprodol in pure form and in pharmaceutical formulations. The developed methods involve formation of coloured chloroform extractable ion-pair complexes of carisoprodol with triphenyl methane dyes viz., bromocresol green (BCG), bromothymol blue (BTB) and bromophenol blue (BPB) in acidic medium. The extracted complexes showed absorbance maxima at 420, 417 and 413 nm with use of BCG, BTB and BPB respectively.  The stoichiometry of the complex in three cases is found to be 1:1.  Beer’s law is obeyed in the concentration ranges: 2.5-25, 2.5-30 and 3.0-30μg/ml with BCG, BTB and BPB 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 all the three methods. These methods have been validated as per the guidelines of International Conference on Harmonization (ICH) and have been applied to the determination of carisoprodol in commercial tablets and results of analysis were validated statistically through recovery studies. Thus the newly developed methods are accurate, efficient and stable.