RESUMO
Three sensitive and reproducible methods for quantitative determination of meloxicam (mel) in pure form and in pharmaceutical formulations are presented. The first method is high performance liquid chromatography by which the drug is determined in the presence of its degradation products over concentration range 100-500 microg x ml(-1) with mean percentage accuracy 100.13+/-0.53. The second method is based on measuring the absorbance of the formed neutral complex between basic methylene blue and mel in phosphate buffer (pH 8) at lambda=653.5 nm over concentration range 1-5 microg x ml(-1) with mean percentage accuracy 99.12+/-1.18. The third method is based on reaction between 2,3-dichloro-5,6-dicyano-p-benzoquinone resulting in the formation of an intense orange red coloured product after heating in a boiling water bath for 5 min. The coloured product exhibits an absorption maximum at 455 nm, over concentration range 40-160 microg x ml(-1) with mean percentage accuracy 100.53+/-1.04.