COMPARATIVE STUDY OF ELECTROSPRAY AND ATMOSPHERIC PRESSURE CHEMICAL IONIZATION WITH LIQUID CHROMATOGRAPHY-MASS SPECTROMETRY FOR QUANTIFICATION OF FIVE ANTIHYPERGLYCEMIC AGENTS UTILIZING MONOLITHIC COLUMN

Liquid chromatography-mass spectrometry (LC-MS) in atmospheric pressure chemical ionization (APCI) and electrospray ionization (ESI) modes were studied for a multi-component plasma and urine quantification of 5 antihyperglycemic agents (metformin, pioglitazone, gliclazide, glibenclamide, and glimperide). The separation of the compounds was achieved using Chromolith Performance RP-18e column (100 x 4.6 mm), with gradient mobile phase composition of acetonitrile -0.1% formic acid. MS parameters for APCI and ESI were optimized individually and were operated in positive mode. The detection limits for the metformin, pioglitazone, glibenclamide, and glimepiride were determined to be 6.84, 6.22, 13.03, and 44.38 ngmL(-1) using LC-ESI-MS; and for LC-APCI-MS, it was determined to be 48.39, 8.02, 17.02, and 144.55 ngmL(-1), respectively. Gliclazide was the only exception as it exhibited a lower limit of detection (LOD) using APCI than ESI which was found to be 5.61 and 23.43 ngmL(-1), respectively. The method was validated for system suitability, linearity, precision and accuracy, specificity, stability, and robustness. The ESI as compared to APCI was found superior in many analytical parameters. The assay has been applied successfully to biological fluids (plasma and urine) of healthy volunteers.