RT Journal Article
SR Electronic
T1 <strong><em>In Vitro</em></strong><strong> Characterization of Ertugliflozin Metabolism by UDP-Glucuronosyltransferase and Cytochrome P450 Enzymes</strong>
JF Drug Metabolism and Disposition
JO Drug Metab Dispos
FD American Society for Pharmacology and Experimental Therapeutics
SP DMD-AR-2020-000171
DO 10.1124/dmd.120.000171
A1 Kimberly Lapham
A1 Ernesto Callegari
A1 Julie Cianfrogna
A1 Jian Lin
A1 Mark Niosi
A1 Christine C. Orozco
A1 Raman Sharma
A1 Theunis C. Goosen
YR 2020
UL http://dmd.aspetjournals.org/content/early/2020/10/01/dmd.120.000171.abstract
AB Ertugliflozin is primarily cleared through UDP‑glucurosyltransferase (UGT)-mediated metabolism (86%) with minor oxidative clearance (12%). In vitro phenotyping involved enzyme kinetic characterization of UGTs or cytochrome P450 (CYP) enzymes catalyzing formation of the major 3-O-β-glucuronide (M5c) and minor 2-O-β-glucuronide (M5a), monohydroxy-ertugliflozin (M1 and M3), and des-ethyl ertugliflozin (M2) metabolites in human liver microsomes (HLM). Fractional clearance (fCL) estimated from HLM intrinsic clearance (CLint) indicated a major role for glucuronidation (fCL 0.96; CLint 37 µL/min/mg) versus oxidative metabolism (fCL 0.04; CLint 1.64 µL/min/mg). Substrate concentration at half-maximal velocity (Km), maximal rate of metabolism (Vmax), and intrinsic clearance (CLint) for M5c and M5a formation were 10.8 µM, 375 pmol/min/mg, 34.7 µL/min/mg and 41.7 µM, 94.9 pmol/min/mg, 2.28 µL/min/mg, respectively. Inhibition of HLM CLint with 10 µM digoxin or tranilast (UGT1A9) and 3 µM 16β-phenyllongifolol (UGT2B7/UGT2B4) resulted in fraction metabolism (fm) estimates of 0.81 and 0.19 for UGT1A9 and UGT2B7/UGT2B4, respectively. Relative activity factor scaling of recombinant enzyme kinetics provided comparable fm for UGT1A9 (0.86) and UGT2B7 (0.14). Km and Vmax for M1, M2, and M3 formation ranged 73.0 - 93.0 µM and 24.3-116 pmol/min/mg, respectively, and was inhibited by ketoconazole and montelukast (M2). In summary, ertugliflozin metabolism in HLM was primarily mediated by UGT1A9 (78%) with minor contributions from UGT2B7/UGT2B4 (18%), CYP3A4 (3.4%), CYP3A5 (0.4%), and CYP2C8 (0.16%). Considering higher ertugliflozin oxidative metabolism (fCL 0.12) obtained from human mass balance, human systemic CL is expected to be mediated by UGT1A9 (70%), UGT2B7/UGT2B4 (16%), CYP3A4 (10%), CYP3A5 (1.2%), CYP2C8 (0.5%), and renal elimination (2%). Significance Statement This manuscript describes the use of orthogonal approaches (i.e., enzyme kinetics, chemical inhibitors and recombinant enzymes) to characterize the fraction of ertugliflozin metabolism through various UGT and CYP enzyme-mediated pathways. Phenotyping approaches routinely used to characterize CYP hepatic fractional metabolism (fm) to estimate specific enzymes contributing to overall systemic CL were similarly applied for UGT-mediated metabolism. Defining the in vitro metabolic disposition and fm for ertugliflozin allows risk assessment when considering potential victim-based DDI perpetrated by co-administered drugs.