A VALIDATED STABILITY-INDICATING METHOD FOR THE DETERMINATION OF RELATED SUBSTANCES AND ASSAY OF PAMIDRONATE SODIUM PENTAHYDRATE BY HPLC WITHOUT DERIVATIZATION

Abstract

ABSTRACT A high performance liquid chromatography (HPLC) method is developed for determination related substances and assay in Pamidronate sodium without derivatization. The isocratic method was developed by using column Zorbax SB-C18 (250 mm x 4.6 mm), 5 µm employing the mobile phase containing the buffer (0.4 % v/v n-Hexylamine in water with pH 7.5): Methanol: Acetonitrile (75:25:05 v/v/v). This method is compatible to conductivity detector, Evaporative Light Scattering (ELS) detector and Refractive Index (RI) detector. The Limit of detection (LOD) and limit of quantitation (LOQ) was established for Pamidronate sodium with Conductivity detector, ELS detector and RI detector. The conductivity detector was found to be suitable for related substances determination in Pamidronate sodium when compared with ELS and RI detectors. The LOQ values obtained for phosphoric acid impurity is 0.05% and phosphorus acid impurity is 0.04% with respect to the target analyte concentration (1 mg mL -1 ) by using conductivity detector. The relative response factor was established by linearity method for phosphoric acid impurity and phosphorous acid impurity against Pamidronate sodium by using conductivity detector. The method was validated with respect to accuracy, precision, linearity and robustness by using conductivity detector. Specificity of the method was demonstrated in the presence of known impurities and degradation impurities