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.
ELECTROCHEMICAL OXIDATION OF MELOXICAM AND ITS DETERMINATION IN TABLET DOSAGE FORM
The oxidative voltammetric behavior of meloxicam at a carbon paste electrode has been studied in Britton-Robinson buffers in the pH range of 2.0–11.5. Meloxicam gave rise to two voltammetric peaks, corresponding to the oxidation of amide and enol functions, respectively. The oxidation process was found to be dependent on the pH of the supporting electrolyte. Using linear-scan voltammetry, the drug yielded well-defined voltammetric response in Britton-Robinson buffer of pH 3.0. The process could be used to determine meloxicam concentration in the range 5.0 × 10−7 − 5 × 10−5M with detection limit of 1.6 × 10−7M. Application of the method to the determination of the drug in the dosage form, without any interference from the excipients, resulted in acceptable deviation from the stated concentration (RSD = 2.2 %).
Stability-Indicating Method for the Determination of Meloxicam and Tetracaine Hydrochloride in the Presence of their Degradation Products
Abstract Sensitive, spectrophotometric and densitometric methdos are described for the determination of meloxicam I and tetracaine hydrochloride II in the presence of their degradation products. Meloxicam was determined in the presence of its degradation products (5-methyl-2-aminothiazole) III and benzothiazine carboxylic acid IV by two methods. These methods are the first derivative Spectrophotometry at 338 nm and TLC densitometric method at 365nm. The methods were applicable over the concentration range of 5–20μg.m−1 and 2–10μg with mean accuracies of 99.66±0.91% and 99.99±0.70% respectively.