Flow-injection analysis for meloxicam based on tris(2,2'-bipyridine) ruthenium(II)-Ce(IV) chemiluminescent system.
It was found that meloxicam could enhance the chemiluminescence (CL) of the tris(2,2'-bipyridine) ruthenium(II)-Ce(IV) system in the medium of sulfate acid. Based on this phenomenon a new flow-injection system with chemiluminescent detection has been proposed for determination of meloxicam. Under optimum conditions, meloxicam had a good linear relationship with the CL intensity in the concentration range of 6.0 10(-4) to 1.0 microg/mL and the detection limit was 3.7 x 10(-4 )microg/mL. The proposed method was applied to detect meloxicam in tablets and a satisfactory recovery was obtained. The possible mechanism for this CL system is also discussed in this paper.
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 microg ml(-1) (method A), 1-10 microg ml(-1) (method B), 4.0-12 microg ml(-1) (method C) and 0.4-1.2 microg ml(-1) (method D). The detection limits were 0.11, 0.07, 0.10, 0.33 and 8.74 x 10(-3) microg 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.
Catalytic removal of tert-butyldimethylsilyl (TBS) ether by PVP-I
Abstract A mild, efficient and rapid protocol the deprotection of alcoholic TBDMS ethers using PVP-1 as catalyst in methanol, the procedure of deprotection of various TBDMS ethers were found to be very convenient, easy work-up, high yielding.