Abstract

SPECTROPHOTOMETRIC DETERMINATION OF DRUGS USING TETRACYANOETHELENE AS ANALYTICAL REAGENT

T. Charan Singh*

Abstract

Five Drugs viz., Cloxacillin, Dextromethorphan, Famotidine, Pyrimethamine, Quetiapine were tested for the formation of charge transfer complexes with Tetracyanoethylene(TCNE). Each of these drugs turned the colourless reagent i.e TCNE., in CH3CN, to pale yellow and exhibited two bands at 400 and 420nm due to anion of the reagent the intensity of these bands increased with increase in the concentration of the drugs and formed a bases for quantitative determination of the drugs the complexes were found to have 1:1 composition and have stability of the order 103 to 104. The effects of reagent concentration, polarity of solvent and interference of excipients have been studied & optimised the Acetonitrile was found to be suitable solvent for the analysis. The methods have been validated in terms of ICH guidelines and applied to the quantification of pharmaceuticals. The variations of slopes of calibration plots and stability constant of the complexes are discussed in terms of structures of drugs.

Keywords: Spectrophotometer, TCNE, Cloxacillin, Dextromethorphan, Famotidine, Pyrimethamine Quetiapine.