Optimized and Validated Spectrophotometric Methods for the Determination of Raloxifene in Pharmaceuticals Using Permanganate

Two simple and sensitive spectrophotometric methods are described for the determination of raloxifene hydrochloride (RLX) in pure form and in tablets. The first method (method A) is based on the formation of a yellowish-brown chromogen peaking at 430 nm when RLX was reacted with permanganate in acetic acid medium. In the second method (method B), RLX was reacted with a measured excess of permanganate in H2SO4 medium followed by the spectrophotometric measurement of the unreacted KMnO4 at 550 nm. Under the optimized experimental conditions, Beer's law is obeyed in the concentration range 0.6-6.0 and 1.5-15.0 mu g mL(-1) with molar absorptivity of 7.01 x 10(4) and 2.8 x 10(4) L mol(-1) cm(-1) for method A and method B, respectively. The limits of detection (LOD) and quantification (LOQ) have also been reported. The intra-day and inter-day RSD and RE values at three different concentrations were assessed. The proposed methods were applied to the commercially available tablets, and the results were statistically compared with those of the reference method. The accuracy and reliability of the methods were further ascertained by recovery studies.