STABILITY INDICATING VALIDATED METHOD FOR THE SIMULTANEOUS ESTIMATION OF DROTAVERINE HCL AND MEFENAMIC ACID IN PURE AND PHARMACEUTICAL DOSAGE FORM BY RP-HPLC

Abstract

A simple isocratic, stability-indicating, rapid, sensitive and robust reversed phase-HPLC method was developed and validated to measure simultaneously the amount of Drotaverine Hcl and Mefenamic acid at single wavelength (245 nm) in order to assess the interference of the excipients over the drug for a new tablet formulation and its subsequent stability studies. There were no analytical methods reported for the simultaneous determination of Drotaverine Hcl and Mefenamic acid in pure and marketed sample. The two drugs were separated using a mobile phase consisting of the mixture acetonitrile: methanol: ortho phosphoric acid buffer {PH adjusted to 3.5 using triethylamine} in the ratio of 50: 30: 20 % v/v/v. Column used was Phenomenex hypersil C18 ODS column 2504.6mm i.d with 5 m particle size The Drotaverine Hcl and Mefenamic acid was carried out using UV detector at 245 nm. The method was found to be specific for Drotaverine Hcl and Mefenamic acid in the presence of degradation products with an overall analytical run time of 7s min. The retention time was found to be 4.3 and 6.2 for Drotaverine Hcl and Mefenamic acid respectively. The method showed a linear response in the concentration range of 40-280 µg/ml for Drotaverine Hcl and 125-875 µg/ml for Mefenamic acid. The results of the analysis were validated statistically by evaluation of accuracy, precision (intra-day and inter day), and linearity parameters as per ICH guidelines. The proposed method can be successfully used to estimate the drug contents of Drotaverine Hcl and Mefenamic acid in pure, marketed formulation and also along with their degraded products.