Liquid chromatographic-electrospray mass spectrometric determination (LC-ESI-MS) of phase II metabolites of flobufen in rat liver microsomes-Chiral discrimination.
Glucuronidation of the non-steroidal anti-inflammatory chiral drug flobufen and its major metabolite M17203 has been implicated as an important mechanism of flobufen elimination. To characterize flobufen metabolism by O-glucuronidation, new liquid chromatographic method (LC) coupled with ESI-MS was developed to detect the conjugates of flobufen and its metabolites formed in vitro in rat liver microsomes. Discovery DSC-18 LT cartridge columns were utilized for solid phase extraction (SPE) and Discovery C18 column (150 mm x 2.1 mm, 5 microm particle size) was used for LC separation. Chiral inversion of flobufen and its metabolites enantiomers was checked by special 1-allyl-(5R,8S,10R)-terguride column (150 mm x 4.6 mm). O-Glucuronidation of the S-enantiomer displayed a typical Michaelis-Menten kinetics, whereas the R-enantiomer exhibited a substrate inhibition type of kinetics. The study of glucuronidation of M17203 led to kinetics with sigmoidal characteristics.
Babú
Yogeeta N
YN
Department of Biochemical Sciences, Charles University, Faculty of Pharmacy, Heyrovského 1203, CZ-50005 Hradec Králové, Czech Republic.
Nemec
Michal
M
Solich
Petr
P
Wsól
Vladimír
V
D000818:Animals; D002087:Butyrates / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
D002087:Butyrates; C056474:flobufen