STABILITY INDICATING RP-HPLC METHOD DEVELOPMENT AND VALIDATION FOR SIMULTANEOUS ESTIMATION OF ISONIAZID AND RIFAMPICIN IN BULK AND SOLID DOSAGE FORMS

ABSTRACT A simple, fast, precise, accurate, robust, economic and stability-indicating reversed phase high performance liquid chromatographic method was developed for the simultaneous estimation of Rifampicin and Isoniazid, using a Hypercil C18 column and a mobile phase composed of Acetonitrile:water 80:20 (v/v). Flow rate was 0.8 mL/min and UV detection wavelength at 303nm. The retention times of Rifampicin and Isoniazid were found to be 2.7 min and 3.3 min respectively. Linearity was established for both Rifampicin and Isoniazid in the range of 10-50 µg/ml respectively. % RSD of Rifampicin and Isoniazid were 1.18 and 1.34 respectively. The correlation co-efficient (r2) of regression was found to be 0.998 and 0.996 for Rifampicin and Isoniazid respectively. The percentage recoveries of Rifampicin and Isoniazid were found to be in the range of 100% and 99.98-100.1% respectively. Both the drugs were subjected to acid, alkali, oxidation and thermal degradation. The degradation studies indicated, both Rifampicin and Isoniazid bulk were degraded under acid, alkali and oxidative stress in only one day. For tablet dosage form of Rifampicin and Isoniazid degraded under acid, alkali stress in only one day as bulk and degraded under oxidation stress in three days. No degradation of both individual Rifampicin and Isoniazid in bulk was observed in Thermal condition (dry heat at 60°C). So this method can be successfully employed for analysis of drug and degradation products in stability samples in industry and simultaneous quantitative analysis of Rifampicin and Isoniazid in bulk drugs and formulations. KEYWORDS: Rifampicin, Isoniazid, Method development, Validation, RP-HPLC, Stress Conditions, Stability Indicating Method, Simultaneous Estimation Method