DEVELOPMENT AND VALIDATION OF SPECTROPHOTOMETRIC METHODS FOR THE QUANTIFICATION OF EFAVIRENZ IN TABLETS

Two simple and precise spectrophotometric methods ( A and B ) were developed for the estimation of efavirenz ( EFZ ) in bulk drug as well as in pharmaceutical dosage form( tablets). Methods A is based on the formation of pink coloured chromogen  by the diazotization and coupling reaction of EFZ with β-Naphthol. The λ max of the pink coloured chromogen was found to be 494nm. Method B is First derivative spectroscopy method. The first derivative spectrum is a plot of the rate of change of absorbance with wavelength against wavelength (dA /dλ versus λ). It is characterized by a maximum, minimum and a cross- over point at the λ max of the absorption band. Beer’s law was obeyed in the concentration range of 10-60µg/ml and 4-24 µg/ml for methods A and B respectively. The proposed methods were statistically validated and found to be useful for the routine determination of EFZ in tablets. Key words: Efavirenz,  β- Naphthol, First derivative spectroscopy, Tablets, Validation