Enzyme kinetic parameters for ertugliflozin metabolite formation in recombinantly expressed CYP and UGT enzymes
Data are expressed as the means ± S.D. from triplicate incubations or means from duplicate experiments. Recombinant enzyme kinetics were scaled to HLM CLint using the HLM Scaling Factors (RAF for UGTs and ISEF for CYPs) as described under Materials and Methods.
| Metabolite | Enzyme | Vmaxa | Km | Km,u | Ksi | rhCLint,ub | HLM scaling factorc,d | HLM CLint,ub | HLM CLint,sc,ub | Combined CLint,sc,u | fm by enzyme familye |
|---|---|---|---|---|---|---|---|---|---|---|---|
| µM | µM | µM | µl·min−1·mg−1 | µl·min−1·mg−1 | ml·min−1·kg−1 | ml·min−1·kg−1 | |||||
| M5a | UGT1A9 | 5.09 ± 0.15 | 135 ± 13 | 14.9 | — | 0.343 | 0.80 | 0.274 | 0.259 | 22.7 | UGT: 0.76 (1A9:2B7 0.86:0.14) |
| UGT2B7 | 6.55 ± 0.28 | 233 ± 28 | 25.6 | — | 0.256 | 2.40 | 0.613 | 0.580 | |||
| M5c | UGT1A9 | 375 ± 5 | 134 ± 6 | 14.7 | — | 25.4 | 0.80 | 20.4 | 19.2 | ||
| UGT2B7 | 2.63 ± 0.18 | 204 ± 46 | 22.4 | — | 0.117 | 2.40 | 2.81 | 2.66 | |||
| M1 | CYP3A4 | 37.0 | 148 | 120 | 1090 | 0.308 | 16.4 | 5.05 | 4.78 | 7.26 | CYP: 0.24 |
| CYP3A5 | 5.47 | 230 | 175 | 1660 | 0.0313 | — | — | — | |||
| CYP2C8f | — | — | — | — | 0.0003 | 55.2 | 0.0184 | 0.0174 | |||
| M2 | CYP3A4 | 11.0 | 167 | 135 | 587 | 0.0815 | 16.4 | 1.34 | 1.27 | ||
| CYP3A5 | 4.93 | 215 | 163 | 771 | 0.0302 | — | — | — | |||
| CYP2C8 | 0.0361 | 32.0 | 28.8 | 568 | 0.00125 | 55.2 | 0.0692 | 0.0654 | |||
| M3 | CYP3A4 | 15.6 | 263 | 213 | 397 | 0.0732 | 16.4 | 1.20 | 1.13 | ||
| CYP3A5 | 1.66 | 495 | 376 | — | 0.0044 | — | — | — | |||
| CYP2C8 | — | — | — | — | — | 55.2 | — | — |
↵a Vmax for UGT metabolism is reported as picomole per minute per milligram protein and for CYP metabolism is picomole per minute per milligram protein.
↵b Ertugliflozin unbound fraction (fu,inc) in rhCYP 3A4 was 0.81 for 0.11 mg/ml protein concentration, 0.11 in HLMs with 2% BSA, 0.76 for 0.16 mg/ml rhCYP 3A5, 0.90 for 0.06 mg/ml protein rhCYP 2C8.
↵c UGT1A9 and UGT2B7 RAFs were generated using mycophenolic acid and zidovudine as probe substrates, respectively.
↵d CYP3A4 CLint ISEF was 0.12 and the CYP abundance was 137 pmol/mg. The CYP2C8 CLint ISEF was 2.3 and CYP abundance was 24 pmol/mg. An ISEF is not available for CYP3A5.
↵e The fm by enzyme family is based on combined CYP and UGT CLint,sc,u.
↵f M1 CYP2C8 CLint,u was determined by slope of formation since solubility prevented determination of individual kinetic parameters.