High-performance liquid chromatographic determination of isoniazid, pyrazinamide, and indomethacin in pharmaceutical preparations

Isoniazid (INH) has been quantitated after precolumn derivatization with 5-methylfuran-2-carboxaldehyde (MFA). Chromatography was performed on a 150 mm × 4.6 mm i.d. YMC-ODS column with water–methanol–tetrahydrofuran, 59:39:2 (v/v) as a mobile phase at a flow rate of 2 mL min-1. Detection was performed at 328 nm. By adoption of this proc-dure pyrazinamide (PZA) and indomethacin (IM) separated completely and could be determined together with INH. Linear calibration plots were obtained between 1.4 and 5.5 µg mL-1 for INH, between 6.2 and 30.8 µg mL-1 for PZA, and between 10.7 and 64.08 µg mL-1 for IM. The method of analysis was used for quantitation of INH, PZA, and IM in pharmaceutical preparations with a coefficient of variation <1%.