Table 4.
Plasma concentrations of ensitrelvir and nirmatrelvir in mice and hamsters
| Plasma concentration | ||||
|---|---|---|---|---|
| Mouse | ETV 16 mg/kg | ETV 32 mg/kg | NTV 1000 mg/kg | |
| t-C24h (ng/mL) | 4820 ± 2500 | 20 700 ± 10 400 | 1010 ± 910 | |
| t-C48h (ng/mL) | 22 400 ± 7500 | 37 700 ± 16 200 | 2050 ± 610 | |
| t-C72h (ng/mL) | 26 100 ± 12 200 | 56 300 ± 22 700 | 2230 ± 650 | |
| f-C24h (ng/mL) | 116 ± 60 | 497 ± 250 | 676 ± 609 | |
| f-C48h (ng/mL) | 538 ± 180 | 905 ± 389 | 1370 ± 410 | |
| f-C72h (ng/mL) | 626 ± 293 | 1350 ± 540 | 1490 ± 430 |
| Hamster | ETV 12.5 mg/kg | ETV 50 mg/kg | NTV 250 mg/kg | NTV 750/250 mg/kg |
| t-C24h (ng/mL) | 587 ± 183 | 7770 ± 4660 | 635 ± 375 | 1370 ± 190 |
| t-C48h (ng/mL) | 4490 ± 1310 | 29 300 ± 5100 | 1290 ± 60 | 1710 ± 470 |
| t-C72h (ng/mL) | 7530 ± 3960 | 16 700 ± 4000 | 1920 ± 600 | 1900 ± 660 |
| f-C24h (ng/mL) | 9.98 ± 3.11 | 132 ± 79 | 378 ± 224 | 817 ± 113 |
| f-C48h (ng/mL) | 76.3 ± 22.3 | 498 ± 87 | 769 ± 36 | 1020 ± 280 |
| f-C72h (ng/mL) | 128 ± 67 | 284 ± 68 | 1140 ± 360 | 1130 ± 390 |
ETV, ensitrelvir; NTV, nirmatrelvir; t-C, total concentration; f-C, unbound drug concentration; Cxxh, plasma concentration at xx h after the first administration of antiviral agent; f-Cxxh = t-Cxxh × (100%−protein binding rate).