A simple polarographic method for the quantitative determination of pyrazinamide (pyrazine monocarboxyl amide) in human blood serum or plasma is described. The method utilizes a rotein-free filtrate obtained b y the use of uranyl acetate. Isoniazid (pyridine-3-cargoxylic acid hydrazide) does not interfere. Pyrazinoic acid (pyrazine monocarboxylic acid) and pyrazinamide give a single wave, but the individual concentrations may be determined by means of a minimum error potential analysis. The sample can be used directly for isoniazid analysis after pyrazinamide determination.
RENEWED interest in the use of pyrazinamide
A in the chemotherapy of tuberculosis has followed reports that the combined therapy of tuberculosis with isoniazid and pyrazinarnide is equal or superior to other treatment regimens
(1, 2, 3). I n following the clinical progress of patients on specific chemotherapy it is desirable to determine, a t appropriate intervals, the serum concentration of the chemotherapeutic agents being used. Since serum biological assay procedures are not easily applied in instances where two or more chemotherapeutic agents are being used simultaneously, there is a need for an accurate and rapid chemical method.
A reported colorimetric method requires the use of ion exchange columns (4). The polarographic method described below eliminates such requirements, thereby lending itself more readily *