A modified method for the estimation of acetylisoniazid in urine.

Abstract

The method of Venkataraman et al. (1968) for the direct estimation of acetylisoniazid in urine has been modified to make it suitable for application to urine specimens containing sugar. The urine is first extracted with a mixture of chloroform and n-butanol, the organic phase re-extracted with dilute sulphuric acid, and the original method then applied to the acid extract. With the modified method, recoveries of acetylisoniazid were quantitative, both in the presence and the absence of glucose. Interference due to hydrazones and isonicotinyl glycine was substantially reduced by the modification, while that due to isoniazid remained the same. There was little or no interference from isonicotinic acid, with either the original or the modified method.