Colorimetric estimation of certain thione compounds of pharmaceutical importance

ABSTRACT

Simple and sensitive spectrophotometric method for the assay of ethionamide, thiopentone sodium and thiacetazone has been reported. The method is based on the formation of stable orange-coloured product with sodium nitroprusside in basic medium which exhibits absorption maxima at wavelengths of 510 nm, 480 nm and 470 nm for ethionamide, thiopentone sodium and thiacetazone respectively. The optimal experimental parameters for the colour production has been worked out. Conformity to Beer's law enables the assay of the studied drugs in their pharmaceutical dosage forms. Recoveries from bulk drugs were 99.99-100.00 with relative standard deviation of +/- 0.235-1.16. The obtained recoveries were in good agreement with those obtained by the official methods: