Metabolic profile of glyburide in human liver microsomes using LC‐DAD‐Q‐TRAP‐MS/MS

Abstract

The sulfonylurea urea drug glyburide (glibenclamide) is widely used for the treatment of diabetes milletus and gestational diabetes. In previous studies monohydroxylated metabolites were identified and characterized for glyburide in different species, but the metabolite owing to the loss of cyclohexyl ring was identified only in mouse. Glyburide upon incubation with hepatic microsomes resulted in 10 metabolites for human. The current study identifies new metabolites of glyburide along with the hydroxylated metabolites that were reported earlier. The newly identified drug metabolites are dihydroxylated metabolites, a metabolite owing to the loss of cyclohexyl ring and one owing to hydroxylation with dehydrogenation. Among the 10 identified metabolites, there were six monohydroxylated metabolites, one dihydroxylated metabolite, two metabolites owing to hydroxylation and dehydrogenation, and one metabolite owing to the loss of cyclohexyl ring. New metabolites of glyburide were identified and characterized using liquid chromatography-diode array detector-quadruple-ion trap-mass spectrometry/mass spectrometry (LC-DAD-Q-TRAP-MS/MS). An enhanced mass scan-enhanced product ion scan with information-dependent acquisition mode in a Q-TRAP-MS/MS system was used to characterize the metabolites. Liquid chromatography with diode array detection was used as a complimentary technique to confirm and identify the metabolites. Metabolites formed in higher amounts were detected in both diode array detection and mass spectrometry detection.

Differences and Similarities in the Metabolism of Glyburide for Various Species: An Analysis by LC-DAD-Q-TRAP-MS/MS

“…Mono-oxygenated metabolites (M1, M2a, M2b, M3, M4 & M5), metabolite owing to loss of cyclohexyl ring (ring loss metabolite, M6), Dihydroxylated metabolite (M7) and metabolites due to hydroxylation and dehydrogenation (M8 & M9) were identified for human. All these metabolites were identified in our previous studies too [6]. Similar to human, metabolic turnover (formation of metabolites) for mouse is also high and metabolites M1, M2a, M2b, M3, M4, M5 and M6 were identified.…”

“…In the previous studies authentic standards of monohydroxylated metabolites were utilized to confirm the formed metabolites from hepatic and placental microsomes of human and baboon [4]. Various scan modes in mass spectrometry and the fragmentation pattern obtained from the mass spectrum was also used to confirm the formed metabolites [5,6]. In the present study glyburide was incubated with hepatic microsomes from various species such as mouse, rat, dog, monkey and the obtained results are compared with the human.…”

“…In our recent studies, we have identified the new metabolites of glyburide in human [5,6]. In the previous studies authentic standards of monohydroxylated metabolites were utilized to confirm the formed metabolites from hepatic and placental microsomes of human and baboon [4].…”

“…The chromatograms (Figures 4-7) are obtained by incubation of glyburide with mouse liver microsomes. Detailed structural elucidation of these metabolites was carried out in the previous studies using human liver microsomes as a matrix [4][5][6]. Chromatograms obtained from the DAD detector is used to quantify the metabolites [7] formed in the system.…”

“…Monohydroxylated metabolites are identified during in vitro incubation of glyburide with hepatic microsomes [4]. Recently, new metabolites such as the metabolite owing to loss of cyclohexyl ring [5], dihydroxylated metabolites, metabolite owing to hydroxylation and dehydrogenation were identified using LC-DAD-Q-TRAP-MS/MS [6]. New metabolites were identified during the incubation of glyburide with human liver microsomes.…”