Electrochemical reduction of meloxicam at mercury electrode and its determination in tablets

The electrochemical reduction of meloxicam has been studied at a mercury electrode using various electrochemical methods in aqueous solutions over a wide pH range. The reduction of the drug produced a single reduction step in acidic media, whereas in slightly acidic and neutral media two reduction steps were observed. In alkaline media meloxicam shows a single pH-independent reduction step. The irreversibility of the electrode process was verified by different criteria. At all pH values, reactant adsorption at mercury electrode was observed. The mechanism of reduction was discussed. Using differential-pulse voltammetry, the drug yielded a well-defined voltammetric response in Britton-Robinson buffer solution, pH 4.0 at -1.286 V (vs. Ag/AgCl). This process could be used to determine meloxicam concentration in the range 1.0 x 10(-8) -5.0 x 10(-6) M. The method was successfully applied for the analysis of meloxicam in the tablet dosage form. (C) 2002 Elsevier Science B.V. All rights reserved.