Abstract
Motesanib diphosphate is a novel, investigational, highly selective oral inhibitor of the receptor tyrosine kinases vascular endothelial growth factor receptors 1, 2, and 3, the platelet-derived growth factor receptor, and the stem cell factor receptor (Kit). The in vitro metabolic profiles of [14C]motesanib were examined by using microsomes and hepatocytes from preclinical species and humans. Several oxidative metabolites were observed and characterized by tandem mass spectrometry, nuclear magnetic resonance spectroscopy, and coinjection with authentic standards. Cytochrome P450 (P450) 3A4 is the major isozyme involved in the oxidative biotransformation of motesanib, but the CYP2D6 and CYP1A isozymes also make minor contributions. In hepatocyte incubations, oxidative and conjugative pathways were observed for all species examined, and indoline N-glucuronidation was the dominant pathway. Three less common and novel phase II conjugates of the indoline nitrogen were detected in hepatocytes and in microsomes supplemented with specific cofactors, including N-carbamoyl glucuronide, N-glucose, and N-linked β-N-acetylglucosamine. An N-glucuronide metabolite was the most frequently observed phase II conjugate in liver microsomes of all species, whereas the N-acetylglucosamine conjugate was observed only in monkey liver microsomes. Incubations with recombinant human UDP-glucuronosyltransferases (UGTs) and inhibition by the UGT1A4 and UGT1A1 substrates/inhibitors imipramine and bilirubin suggested that UGT1A4 is the major UGT isozyme catalyzing the N-glucuronidation of motesanib, with a minor contribution from UGT1A1. The in vitro metabolic profiles were similar between the human and preclinical species examined. All metabolites found in humans were also detected in other species.
Footnotes
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This work was funded by Amgen Inc. (Thousand Oaks, CA).
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Article, publication date, and citation information can be found at http://dmd.aspetjournals.org.
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doi:10.1124/dmd.108.025742.
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ABBREVIATIONS: VEGF, vascular endothelial growth factor; PDGF, platelet-derived growth factor; Kit, stem cell factor receptor; P450, cytochrome P450; UGT, UDP-glucuronosyltransferase; M3, oxidative metabolite of motesanib, pyridine N-oxide; M4, oxidative metabolite of motesanib, lactam (oxindole); M1, conjugative metabolite of motesanib, indoline N-glucuronide; HPLC, high-pressure liquid chromatography; DAD, diode array detector; GA, glucuronic acid; HLM, human liver microsome; M5, oxidative metabolite of motesanib, carbinolamine; Ma, conjugative metabolite of motesanib, indoline N-carbamoyl glucuronide; LC/MS/MS, liquid chromatography/tandem mass spectrometry; ESI, electrospray ionization; LC/MS, LC/mass spectrometry; Mx, oxidative N-dealkylated metabolite of motesanib, isonicotinic acid; Q-TOF, quadrupole time-of-flight; 1D, one dimensional; 2D, two dimensional; HMBC, heteronuclear multiple bond correlation; Mb, conjugative metabolite of motesanib, indoline N-glucose; Mc, conjugative metabolite of motesanib, indoline N-N-acetylglucosamine; M2, oxidative metabolite of motesanib, structure unassigned; Miv, oxidative N-dealkylated metabolite of motesanib, lactam of Mv; Mv, oxidative N-dealkylated metabolite of motesanib, 2-amino nicotinamide; CID, collision-induced dissociation; ILT-threo, l-threo isoleucine thiazolidide [(2S,3S)-3-methyl-1-oxo-1-(1,3-thiazolidin-3 yl)-pentan-2-amine fumarate (2:1)].
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↵1 Current affiliation: Pharmacokinetics and Drug Metabolism, Pharmacology Department, Genomics Institute of the Novartis Research Foundation, San Diego, California.
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↵2 Drug Metabolism and Pharmacokinetics, Early Drug Development, Celgene Corporation, Summit, New Jersey.
- Accepted April 13, 2009.
- Received November 19, 2008.
- The American Society for Pharmacology and Experimental Therapeutics
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In Vitro Metabolism of the Novel, Highly Selective Oral Angiogenesis Inhibitor Motesanib Diphosphate in Preclinical Species and in Humans
