Human mass balance, pharmacokinetics and metabolism of rovatirelin and identification of its metabolic enzymes in vitro.
The mass balance, pharmacokinetics and metabolism of rovatirelin were characterised in healthy male subjects after a single oral dose of [14C]rovatirelin. [14C]Rovatirelin was steadily absorbed, and the peak concentrations of radioactivity and rovatirelin were observed in plasma at 5-6 h after administration. The AUCinf of radioactivity was 4.9-fold greater than that of rovatirelin. Rovatirelin and its metabolite (thiazoylalanyl)methylpyrrolidine (TAMP) circulated in plasma as the major components. The total radioactivity recovered in urine and faeces was 89.0% of the administered dose. The principal route of elimination was excretion into faeces (50.1% of the dose), and urinary excretion was the secondary route (36.8%). Rovatirelin was extensively metabolised to 20 metabolites, and TAMP was identified as the major metabolite in plasma and excreta among its metabolites. To identify the metabolic enzymes responsible for TAMP formation, the in vitro activity was determined in human liver microsomes. The enzymatic activity depended on NADPH, and it was inhibited by ketoconazole. Furthermore, recombinant human cytochrome P450 (CYP) 3A4 and CYP3A5 displayed enzymatic activity in the assay. Therefore, CYP3A4/5 are the most important enzymes responsible for TAMP formation.
['Kobayshi|Kaoru|K|', 'Abe|Yoshikazu|Y|', 'Kawai|Asuka|A|', 'Furihata|Takao|T|', 'Harada|Hiroshi|H|', 'Endo|Takuro|T|', 'Takeda|Hiroo|H|']
D000284:Administration, Oral D000328:Adult D019540:Area Under Curve D002250:Carbon Radioisotopes D002853:Chromatography, Liquid D051544:Cytochrome P-450 CYP3A D005243:Feces D006801:Humans D008658:Inactivation, Metabolic D008297:Male D008875:Middle Aged D023303:Oxazolidinones D011759:Pyrrolidines D011994:Recombinant Proteins D053719:Tandem Mass Spectrometry
Rovatirelin metabolic enzyme CYP3A4/5 TRH analogue human mass balance study reaction phenotyping