Development and Validation of a Novel Stability Indicating High – Performance Liquid Chromatography Method for Simultaneous Determination of Paracetamol and Lornoxicam

A simple, specific, accurate and stability-indicating reversed phase high performance liquid chromatographic method was developed for the simultaneous determination of paracetamol and lornoxicam from pharmaceutical dosage forms. The method uses RP-18 column and isocratic elution. The mobile phase composed of methanol: ammonium acetate (pH 8, 10 mM) in the ratio of 50:50%v/v was used at a flow rate of 1mL/min. The detection was achieved with a diode array detector at 290 nm. The retention time of paracetamol and lornoxicam were found to be 2.7 and 7.2 min, respectively. The method was linear in the concentration range of 8–80 μg/mL. The specificity and stability indicating capability of the method were proved through stress studies. The degradation studies indicated that both paracetamol and lornoxicam were susceptible to acid and alkali hydrolysis. The degradation products of paracetamol and lornoxicam were well resolved from the pure drugs with significant differences in the retention time. The percentage recoveries of paracetamol and lornoxicam were found to be 99.88±0.1617% and 99.78±0.3235%, respectively. The method developed can be effectively applied for the simultaneous estimation of paracetamol and lornoxicam in bulk drugs and formulations in presence of degradation products.