Oral pharmacokinetics of meloxicam in the rat using a high-performance liquid chromatographic method in micro-whole blood samples

The pharmacokinetics of meloxicam, a potent analgesic and antiinflammatory drug used in several rheumatic diseases, has been studied in rats that received oral doses of 3.2, 5.6 or 10 mg/kg of meloxicam. Blood samples were obtained at selected times during 24 h after administration, and meloxicam concentrations were determined by a validated high-performance liquid chromatography (HPLC) method, using micro-whole-blood samples, developed in our laboratory. After administration of meloxicam, blood concentrations increased reaching a dose-dependent maximal concentration in about 2 h. Then, concentrations decayed with a half-life of 9 h. An increase in C(max) and AUC as a function of the dose was observed, and no statistically significant difference was observed in AUC/dose or C(max)/dose between doses. However, linearity could not be concluded because of the wide variability observed.