Identification and clearance involved in the formation of glucuronides of RT-3003, a new peripheral blood flow enhancer, and its metabolite in rats.
Glucuronides of RT-3003 and its metabolite (9-OH-RT-3003), which was hydroxylated at the 9 position on the benzene ring, were separated by HPLC and identified by liquid chromatography (LC)/MS/MS and NMR. The conjugation sites of these glucuronides were determined by nuclear Overhauser effects (NOE) irradiation; RT-3003 was conjugated at an alcoholic hydroxyl group of the hydroxymethyl moiety, and 9-OH-RT-3003 at a phenolic hydroxyl group on a benzene ring and at an alcoholic hydroxyl group of a hydroxymethyl moiety. On a reversed-phase HPLC of 9-OH-RT-3003, alcoholic glucuronide was eluted later than phenolic glucuronide, indicating the high hydrophobicity of alcoholic glucuronide. Clearance for the glucuronidation (ClG) of RT-3003 was lower than the summation of ClG for two types of glucuronidation of 9-OH-RT-3003. ClG of 9-OH-RT-3003 was high in phenolic glucuronide. The activity of UDP-glucuronyltransferase (UDPGT) for RT-3003 was 9.63 times that for 9-OH-RT-3003, and the activity ratio of the two types of glucuronidation of 9-OH-RT-3003 was similar to the ratio of the corresponding ClG. The difference between ClG and UDPGT activity is discussed in association with clearance for the hydroxylation and interaction of substrates with UDPGT.
Kaburagi
T
T
Institute of Xenobiotic Analyses, Inba, Chiba, Japan.
Yoshitsugu
H
H
Uekusa
H
H
Ishibashi
M
M
Nanbo
T
T
D000818:Animals; D001646:Bile / Q000378:metabolism; D002250:Carbon Radioisotopes; D002853:Chromatography, Liquid; D020719:Glucuronides / Q000378:metabolism / Q000493:pharmacokinetics*; D014453:Glucuronosyltransferase / Q000378:metabolism; D006900:Hydroxylation; D007211:Indoles / Q000378:metabolism / Q000493:pharmacokinetics*; D008297:Male; D013058:Mass Spectrometry; D019906:Nuclear Magnetic Resonance, Biomolecular; D011807:Quinolizines / Q000378:metabolism / Q000493:pharmacokinetics*; D051381:Rats; D017208:Rats, Wistar; D012039:Regional Blood Flow / Q000187:drug effects
D002250:Carbon Radioisotopes; D020719:Glucuronides; D007211:Indoles; D011807:Quinolizines; D014453:Glucuronosyltransferase; C066359:vintoperol