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 microg 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.

Gradient HPLC analysis of raloxifene hydrochloride and its application to drug quality control.

A rapid, sensitive and selective method for the determination of raloxifene hydrochloride (RLX) in pure drug and in tablets was developed using gradient high performance liquid chromatography (HPLC). The devised method involved separation of RLX on a reversed phase Hypersil ODS column and determination with UV detection at 284 nm. The standard curve was linear (R = 0.999) over the concentration range of 50-600 microg mL-1 with a detection limit of 0.04 microg mL-1 and a quantification limit of 0.16 microg mL-1. Intra-day and inter-day precision and accuracy of the method were established according to the current ICH guidelines. Intra-day RSD values at three QC levels (250, 450 and 550 microg mL-1) were 0.2-0.5%, based on the peak area. The intra-day relative error (er) was between 0.2 and 0.5%. The developed method was successfully applied to the determination of RLX in tablets and the results were statistically compared with those obtained by a literature method. Accuracy, evaluated by means of the spike recovery method, was the excellent with percent recovery in the range 97.7-103.2 with precision in the range 1.6-2.2%. No interference was observed from the co-formulated substances. The method was economical in terms of the time taken and the amount of solvent used.