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ACETYLATION PHENOTYPING OF ISONIAZID USING A SIMPLE AND ACCURATE HIGH‐PERFORMANCE LIQUID CHROMATOGRAPHY
Author(s) -
ElSayed Y. M.,
Islam S. I.
Publication year - 1989
Publication title -
journal of clinical pharmacy and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.622
H-Index - 73
eISSN - 1365-2710
pISSN - 0269-4727
DOI - 10.1111/j.1365-2710.1989.tb00238.x
Subject(s) - isoniazid , chromatography , high performance liquid chromatography , chemistry , metabolite , urine , elution , acetonitrile , chloroform , extraction (chemistry) , medicine , biochemistry , tuberculosis , pathology
Summary A simple, specific, accurate and reproducible method for the analysis of isoniazid and its major metabolite, N ‐acetylisoniazid in urine using high‐performance liquid chromatography (HPLC) is described. The assay is performed after extraction of isoniazid, N ‐acetylisoniazid and 5‐(4‐methylphenyl)‐5‐phenylhydantoin (internal standard) from urine using a mixture of chloroform: isopropanol (70:30, v/v) and eluted from a 5 urn C‐18 reversed phase column at ambient temperature with a mobile phase consisting of 10 mM sodium acetate: methanol: acetonitrile (40:40:20, v/v) containing 10 mM dioctylsulphosuccinate sodium and adjusted to pH 2·9 with sulphuric acid (< 1 ml), at a flow rate of 1 ml/min with u.v. detection at 266 nm. Quantification was achieved by the measurement of the peak height ratio, and the absolute recoveries ranged from 94 to 99%. Within‐day coefficients of variation ranged from 2·81 to 4·54% for isoniazid and from 2·37 to 3·75% for N ‐acetylisoniazid. Between‐day CVs varied from 3·27 to 5·62% and from 2·5 to 4·91% for isoniazid and N ‐acetylisoniazid, respectively. Preliminary stability tests using a urine sample from a subject showed an increase in mean isoniazid concentration of about 25% after 1 month storage at ‐ 20°C. The method was used for acetylation phenotyping of five individuals.