Simultaneous determination of paracetamol and lornoxicam by RP-HPLC in bulk and tablet formulation

Aim: The objective of the study was to develop simple RP-HPLC method for the simultaneous determination of paracetamol and lornoxicam without prior séparation. Materials and Methods: In this method, Kromasil C8 (250 mm, 4.6 mm, 5 μm) column was used. The mobile phase used was methanol:phosphate buffer (60:40, v/v, pH 6.4), at flow rate of 1 ml min- 1. UV detection was monitored at 302 nm. Results: Calibration graphs were established in the range of 1-150 μg ml- 1 and 0.5-100 μg ml- 1 for paracetamol and lornoxicam, respectively. The average retention time for paracetamol and lornoxicam was found to be 3.15 ± 0.03 min and 5.25 ± 0.06 min, respectively. The detection limit and quantitation limit for paracetamol are 0.19 μg ml- 1 and 0.59 μg ml- 1 and for lornoxicam 0.10 μg ml- 1 and 0.31 μg mL- 1, respectively. The intraday and interday precision expressed as percent relative standard deviation were below 2%. The mean recovery of paracetamol and lornoxicam was found to be in the range of 99.03-101.2%. Conclusion: The validated HPLC method was found to be rapid, precise and accurate and can be readily utilized for analysis of paracetamol and lornoxicam in bulk and in pharmaceutical formulations.