Spectrophotometric methods for determining meloxicam in pharmaceuticals using batch and flow-injection procedures.

Two sensitive and fast spectrophotometric methods using batch and flow-injection procedures for the determination of meloxicam (MX) are proposed. The methods are based on the formation of a green complex between this drug and Fe(III) [2MX/Fe(III)] in a methanolic medium. The calibration graphs resulting from measuring the absorbance at 570 nm are linear over the ranges 2.0-200 and 5.00-250 mg l(-1) with detection limits of 0.47 and 0.72 mg l(-1), respectively. Furthermore, a flow-injection spectrophotometric method involving measurement of the absorbance of the drug at 362 nm in 0.1 M NaOH is presented. The calibration graph is linear over the range 0.5-20 mg l(-1) with a detection limit of 0.04 mg l(-1). The methods are applied to the routine analysis of MX in pharmaceuticals.