Intrinsic clearance rate of O-desmethyltramadol (M1) by glucuronide conjugation and phase I metabolism by feline, canine and common brush-tailed possum microsomes

Quantitative aspects of in vitro phase II glucuronidative metabolism of O-desmethyltramadol (O-DSMT or M1), the active metabolite of the analgesic drug tramadol, by feline, canine and common brush-tailed possum hepatic microsomes are described.Whilst previous studies have focused on the phase I conversion of tramadol to M1, this is the first report in which the phase II glucuronidative metabolic pathway of M1 has been isolated by an in vitro comparative species study.Using the substrate depletion method, microsomal phase II glucuronidative in vitro intrinsic clearance (Clint) of M1 was determined.The in vitro Clint (mean ± SD) by pooled common brush-tailed possum microsomes was 9.9 ± 1.7 μL/min/mg microsomal protein whereas the in vitro Clint by pooled canine microsomes was 1.9 ± 0.07 μL/min/mg microsomal protein. The rate of M1 depletion by feline microsomes, as measured solely by high pressure liquid chromatography, was too slow to determine. Liquid chromatography-mass spectrometry identified O-DSMT glucuronide in samples generated from all three species' microsomes, although the amount detected under the feline condition was minimal.This study indicates that M1 likely undergoes in vitro phase II glucuronidation by canine and common brush-tailed possum microsomes and, to a minor extent, by feline microsomes. The rate of depletion of M1 by phase I metabolism was also undertaken.When incubated with phase I co-factors and common brush-tailed possum microsomes or canine microsomes, M1 had an in vitro Clint of 47.6 and 22.8 μL/min/mg microsomal protein, respectively. However, due to a lack of CYP2B-like activity in the feline liver, unsurprisingly, M1 did not deplete when incubated with feline microsomes. Consequently, major M1 elimination pathways, using feline microsomes, were not determined.".

Medienart:

E-Artikel

Erscheinungsjahr:

2020

Erschienen:

2020

Enthalten in:

Zur Gesamtaufnahme - volume:50

Enthalten in:

Xenobiotica; the fate of foreign compounds in biological systems - 50(2020), 7 vom: 22. Juli, Seite 776-782

Sprache:

Englisch

Beteiligte Personen:

Izes, Aaron M [VerfasserIn]
Kimble, Benjamin [VerfasserIn]
Govendir, Merran [VerfasserIn]

Links:

Volltext

Themen:

2WA8F50C3F
39J1LGJ30J
Cat
Common brush-tailed possum
Dog
Glucuronidation
Glucuronides
Intrinsic clearance
Journal Article
M1
Microsome
O-demethyltramadol
O-desmethyltramadol
Phase II hepatic metabolism
Tramadol

Anmerkungen:

Date Completed 21.07.2020

Date Revised 21.07.2020

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1080/00498254.2019.1697014

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM303579560