Studies on the Change of Thioacetazone in vivo. II

Colorimetric Determination of Thioacetazone in Urine and its Excretion

Abstract

p-Dimethylaminobenzaldehyde, which had earlier been used for the measurement of blood level of p-acetylaminobenzaldehyde thiosemicarbazone (thioacetazone), was utilized for measuring its concentration in the urine and a sensitive method for determining thioacetazone alone, removing any interfering material contained in the urine, was devised. The value obtained by this method is that of thioacetazone alone, excluding majority of the biological decomposition products of thioacetazone. By the combination of the present method and the diazotization method to measure the amount excreted, the difference of the two values gives the rate of biological decomposition of thioacetazone and the values so obtained showed that 100mg of its powder taken orally resulted in an average of about 40% decomposition and excretion. Enteric-coated tablets were also found to be decomposed to a fair extent. Application of this method in the presence of INAH, PAS, or streptomycin resulted in complete removal of INAH. The effect of 2% solution of PAS on the present method was below approx. 0.2mg% calculated as thioacetazone.