Extraction and Quantification of Lornoxicam in Human Plasma by Liquid Chromatography-Tandem Mass Spectrometry in Positive Ion Mode

Abstract

A novel liquid chromatography tandem mass spectrometry method is described for the quantitative determination of lornoxicam in human K₂ EDTA plasma in positive ion mode and validated using piroxicam as internal standard according to linearity, selectivity, precision, recovery and various stability studies. Sample preparation was accomplished by liquid liquid extraction technique. The eluted samples were chromatographed on ACE C18 (150 × 4.6 mm, 5 μ) column (agilent technologies) using a mobile phase consisting of HPLC grade acetonitrile: 0.3 % formic acid buffer (80:20 v/v) with injection volume of 15 μL and a run time of 3 min. The precursor to product ion transitions m/z 372.10 to 121.10 (lornoxicam) and m/z 332.10 to 95.20 (piroxicam, IS) were used for quantization. The calibration graph of lornoxicam was linear with r² > 0.990 over a concentration range of 5.086 ng/mL to 1518.325 ng/mL. CV % of intra- and inter-day precisions were found satisfactory and well within the limits. The drug was found to be stable for the studied parameters and found to be interference free for matrix effect with appreciable recovery. The novelty of the method makes it highly valuable, rapid, selective and sencitive for quantification of lornoxicam in human plasma and can be used in therapeutic drug monitoring of this drug.