Ion interaction reagent reversed-phase high-performance liquid chromatography determination of anti-tuberculosis drugs and metabolites in biological fluids

New methods of ion interaction reagent (IIR) RP-HPLC are presented for the determination of anti-tuberculosis drugs and their metabolites, singly or i n multi-component mixtures, in biological fluids. The following analytes ar e considered: isoniazid, ethionamide, pyrazinamide, morphazinamide, p-amino salicylic acid, nicotinic and isonicotinic acids. Aqueous solutions of thre e different ion interaction reagents are alternatively or comparatively use d as the mobile phases, namely: (A) 5.00 mM octylamine at pH 3.00 for o-pho sphoric acid, (B) 5.00 mM octylamine at pH 8.00 for o-phosphoric acid, and (C) 5.00 mM 1,6 diaminohexane at pH 6.00 for o-phosphoric acid. The respons e linearity between peak area and analyte concentration is verified fur all the analytes in the concentration range within the determination limits an d 2.00 mg/l, Detection limits are always lower than 82 mug/l for standard s olutions; in the analysis of samples of rat serum, rat plasma and human ser um, the matrix effect is negligible, the detection limits are always lower than 94 mug/l and the average recovery yield is always greater than 96%. (C ) 2001 Elsevier Science B.V. All rights reserved.