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. Detection was performed at 328 nm. By adoption of this procedure 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 for INH, between 6.2 and 30.8 μg mL for PZA, and between 10.7 and 64.08 μg mL for IM. The method of analysis was used for quantitation of INH, PZA, and IM in pharmaceutical preparations with a coefficient of variation <1%.