Two new simple, sensitive, rapid, accurate and reproducible methods (spectrophotometric and ion pair chromatography) have been developed for simultaneous estimation of verapamil (VER) from its pure and tablet dosage form. The first method involves multiwavelength spectrophotometric method (Method I) in which interference of HCTZ at 245 nm (wavelength for estimation of VAL) was removed by recording absorbance difference at 245 nm and 301 nm whereas HCTZ was estimated directly from its absorbance at 316 nm at which VAL shows no absorbance. Linearity of the response was demonstrated by VER in the concentration range of 10-60 g/ml with a square correlation coefficient (r2) of 0.9992. The second method utilizes ion pair chromatography (Method 2) on a HIQ sil ODS column (250 mm x 4.6 mm i.d.) using a mobile phase consisting methanol:water (70:30 v/v) pH adjusted to 7.4 with orthophosphoric acid and addition of 1% 1-hexanesulfonic acid monohydrate sodium salt as an ion pair reagent with UV detection at 220 nm over concentration range for VER is 10-90 µg/ml. Atenolol was used as the internal standard. The suggested procedures were checked using laboratory prepared mixtures and were applied successfully for the analysis of their tablet dosage form. The results of analysis were statistically analysed. Both the methods were validated as per ICH Q2B guidelines.
Loading....