Abstract

Monitoring of anti-tuberculosis drug concentrations in human plasma is very important in the treatment of TB disease. In this study, we described a method that can rapidly and simultaneously measure the plasma concentrations of four anti-tuberculosis drugs (isoniazid, rifampicin, pyrazinamide, and ethambutol) and one major metabolite (acetylisoniazid) using high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS). To adjust for degradation and losses during sample preparation, Diltiazem hydrochloride were used as internal standard. Samples were prepared by using protein precipitation with methanol. Four drugs and one metabolite were simultaneously separated by using high performance liquid chromatography system with Gemini C18 column and mobile phase consisting of MeOH and Ammonium acetate 5mM, pH 3.5. The method was found to have high selectivity. Precision estimated by the coefficient of variation was

Key words: Pyrazinamide; Rifampicin; Isoniazid; Acetyl Isoniazid; Ethambutol; LC-MS/MS; Tuberculosis;