Determination of Meloxicam in Human Plasma by HPLC and Evaluation of Its Bioequivalence Assessment

A sensitive HPLC method for the determination of meloxicam in human plasma was established and the bioequivalence of two MLX was studied. HPLC system consisted of a discovery C\-\{18\} column (5 μm, 250 mm×\{4.6 mm)\} and a mobile phase of methanol H\-2O (75∶25, adjusted pH 4.5 with HOAc ). The UV detector was 355 nm. 5 chloro 2 amino benzophenone was setected as an internal standard. The drug was extracted with ether n hexane(2∶1) after acidification with HCl. The calibration curve was linear in the range from 0.05~2.50 μg/ml with r=0.9998. The relative standard deviations for within day and between day were all 7.0%, and the recoveries of MLX were 90%. A single oral dose of 15 mg domestic and imported MLX tablet was given to 18 healthy volunteers in a randomized crossover study. The results showed that AUC 0→96 were 53.55±11.74 μg·h/ml and 54.53±11.18 μg·h/ml ; C max were 1.549±0.328 μg/ml and 1.580±0.342 μg/ml; T max were 5.6±2.7 h and 5.6±2.3 h for domestic and imported tablet respectively. Relative bioavailability was 98.5%±\{11.2%.\} The results showed that the two formulations were bioequivalent.