Optimization and validation of RP-HPLC method for the estimation of meloxicam and paracetamol with its genotoxic impurity (p-amino phenol) in bulk and pharmaceutical drug product using PDA detector

A simple, accurate, precise, reproducible RP-HPLC method has been developed for simultaneous estimation of meloxicam and paracetamol with its genotoxic impurity (p-amino phenol) in bulk and combined dosage form (tablet). The method was validated in compliance with ICH guidelines[1-2]. The LC separation was achieved on Lichrospher RP-18e (250X4.6mm), 5μm column at 285 nm in isocratic mode using mobile phase composition Methanol: Phosphate buffer (80:20 v/v), pH adjusted to 2.6 by orthophsphoric acid. Flow rate employed was 1.0 ml/min. The retention time for paracetamol, meloxicam and p-amino phenol were found to be 2.28, 3.14 and 6.09 minutes respectively. Linearity ranges were suitable for routine determination(10-120 μg/ml, 1-20 μg/ml 1-10μg/ml) of Paracetamol, Meloxicam and p-Amino phenol with correlation coefficient of 0.9991, 0.9992 and 0.9990 respectively. The % recoveries were in the range of 99.8 ±0.14 for paracetamol, 99.50± 0.52 for meloxicam and 99.4±0.68 for p-amino phenol impurity with relative standard deviation(RSD) less than 2. The LOD and LOQ were found to be 0.1692 and 0.5073 for Meloxicam, 0.2669 and 0.8007 for Paracetamol, 0.1040 and 0.3120 for p-amino phenol respectively. The proposed method is successfully appplied for the quantification of paracetamol, meloxicam and p-amino phenol impurity in bulk and formulations.