DEVELOPMENT AND VALIDATION OF STABILITY INDICATING RP-HPLC METHOD FOR SIMULTANEOUS ESTIMATION OF ISOSORBIDE DINITRATE AND HYDRALAZINE HCL IN COMBINED PHARMACEUTICAL DOSAGE FORM

A simple, sensitive ,linear, precise and accurate PR - HPLC method for simultaneous estimation of isosorbide dinitrate and hydralazine hydrochloride, in tablet formulation was developed, validated and forced degradation studies were conducted. The chromatogra phic separation of the two drugs was achieved on INERTSIL ODS C 18 (150 x 4.6 *5μ) column in an isocratic mode. The mobile phase consisting of 0.1M sodium dihydrogen phosphate:methanol in the ratio of 80:20 v/v and was delivered at a flowrate of 1ml/min and effluents were monitored at 270nm. The retention time of was found to be 1.679 and 3.430 min, respectively. Calibration curve s were linear with acorrelation coefficient of 0.994 for HYD, and 0.997 for ISDN over the concentration range of 160 - 480 ? g/ml for ISDN, and 300 - 900 ? g/ml for Hydralazine HCl and precise with (%RSD <2). The method was validated as per the ICH guidelines and drugs were found to be stable under forced degradation conditions and can be employed for routine Q.C.analysis