Spectrophotometric determination of indinavir in bulk and pharmaceutical formulations using bromocresol purple and...

A simple, sensitive and selective method for the determination of indinavir (IND) in bulk and in pharmaceutical formulations is described. The method is based on extraction of this drug into chloroform as ion-pair with sulphonphthalein dyes as bromocresol purple (BCP) and bromothymol blue (BTB). The optimum conditions of the reactions were studied and optimized. The absorbance of the yellow products was measured at 427 nm for IND-BCP and 420 nm for IND-BTB. The calibration graphs were linear over the range 4.0-60.2 microg x ml(-1) of drug in chloroform, using the two dyes. The composition of the ion-pairs was established by the molar ratio method. For IND the molar ratio was determined to be 1:1 by measurement of first derivative signals at 273 nm. A calibration graph was established for 3.0-70.6 microg x ml(-1) of IND for first derivative spectrophotometry. The developed method was applied successfully for the determination of IND in pharmaceutical formulations. The data obtained were compared the data given by first derivative spectrophotometry. No differences were found.