Spectrophotometric and fluorimetric methods for the determination of meloxicam in dosage forms

Four simple and accurate methods are presented for the determination of meloxicam in dosage forms. These methods are based on: the direct measurements of the differential spectra at 339.9–384.7 nm (A), the 1D-values at 322–368 nm and 2D-values at 343.2–385.6 nm (B), the formation of an ion-association complex between the drug and safranin T with subsequent absorption measurement at 518 nm (C) and fluorescence measurement at 582 nm (D). All variables were studied to optimize the formation of the ion-association complex. Beer's law was valid over the concentration range 2–10 μg ml −1 (method A), 1–10 μg ml −1 (method B), 4.0–12 μg ml −1 (method C) and 0.4–1.2 μg ml −1 (method D). The detection limits were 0.11, 0.07, 0.10, 0.33 and 8.74×10 −3 μg ml −1 for methods A, B, C and D, respectively. The proposed methods were successfully applied to the assay of meloxicam in tablets and suppositories. The procedures were rapid, simple and suitable for quality control applications.