A simple method for determination of nimesulide in rat blood samples by high-performance liquid chromatography

A rapid and simple method for determination of nimesulide in blood samples, by high-performance liquid chromatography, was developed. This method incl udes a single extraction of acidified blood (1N hydrochloric acid) with die thyl ether. Blood extracts were analyzed on a reversed-phase column eluted with a mixture of methanol-0.05 M potassium dihydrogen phosphate solution ( pH 5) and detected by absorbance at 290 nm. Retention times for the internal standard and nimesulide were 4.2 and 8.2 m in, respectively. The method was linear in the range of 0.2 to 5 mu g/mL an d the detection limit of the method was 40 ng/mL. This method is suitable f or determination of nimesulide after oral administration, and could be used for pharmacokinetic studies of the drug in the rat using small volume samp les.