Gradient elution mode for the troubleshooting of matrix effect on the determination of G004 in different tissues by...

A steep gradient elution mode was applied to reduce the risk of matrix effect (ME) for the determination of G004, a novel sulfonylurea hypoglycemic drug, in a tissue distribution study by LC-MS/MS. The mass spectra of the total-ion-current chromatograms combined with the post-column infusion traces enabled the 'unseen' interfering species to be directly detected, and ensured that the chromatography conditions and sample preparation method were adequate to overcome the ME. According to this, a steep gradient elution mode was designed to overcome the intense ME from different tissues. The analysis was performed by monitoring the transitions m/z 558.1 → 419.0 for G004 and m/z 489.3 → 364.1 for glimepiride used as the internal standard. Calibration curves recovered over a range from 0.1 to 10000 ng/mL for seven different tissues. Sex-related difference was found in the tissue distribution. The drug levels in the tissues of female rats were about two to three times higher than those in male counterparts. The highest level was observed in liver, then in kidney, heart, pancreas, lung and spleen, but no G004 was detected in brain. G004 was slowly eliminated from female rats compared with male rats. There was no long-term accumulation of G004 in male or female rat tissues.