Absorption
Eravacycline is administered intravenously and therefore has 100% bioavailability.
The mean pharmacokinetic parameters of eravacycline after single and multiple intravenous infusions (60 minutes) of 1 mg/ kg administered to healthy adults every 12 hours are presented in Table 3.
Table 3 Mean (%CV) plasma pharmacokinetic parameters of eravacycline after single and multiple intravenous infusions to healthy adults
| Eravacycline dosing | | PK parameters arithmetic mean (%CV) |
| Cmax (ng/mL) | tmaxa (h) | AUC0-12b (ng*h/mL) | t1/2 (h) |
| 1.0 mg/kg intravenous every 12 hours (n=6) | Day 1 | 2125 (15) | 1.0 (1.0-1.0) | 4305 (14) | 9 (21) |
| Day 10 | 1825 (16) | 1.0 (1.0-1.0) | 6309 (15) | 39 (32) |
a Mean (range) represented
b AUC of Day 1 = AUC 0-12 after the first dose and AUC for Day 10 = steady state AUC0- 12
Distribution
The in vitro binding of eravacycline to human plasma proteins increases with increasing concentrations, with 79%, 86% and 90% (bound) at 0.1, 1 and10 μg/mL, respectively. The mean (%CV) volume of distribution at steady-state in healthy normal volunteers following 1 mg/kg every 12h is approximately 321 L (6.35), which is greater than total body water.
Biotransformation
Unchanged eravacycline is the major medicinal product-related component in human plasma and human urine. Eravacycline is metabolised primarily by CYP3A4- and FMO-mediated oxidation of the pyrrolidine ring to TP-6208, and by chemical epimerisation at C-4 to TP-498. Additional minor metabolites are formed by glucuronidation, oxidation and hydrolysis. TP-6208 and TP-498 are not considered to be pharmacologically active.
Eravacycline is a substrate for the transporters P-gp, OATP1B1 and OATP1B3 but not for BCRP.
Elimination
Eravacycline is excreted in both urine and faeces. Renal clearance and biliary and direct intestinal excretion account for approximately 35% and 48% of total body clearance after administration of a single intravenous dose of 60 mg 14C-eravacycline, respectively.
Linearity/non-linearity
The Cmax and AUC of eravacycline in healthy adults increase approximately in proportion to an increase in dose. There is approximately a 45% accumulation following intravenous dosing of 1 mg/kg every 12 hours.
Within the range of eravacycline multiple intravenous doses studied clinically, the pharmacokinetic parameters AUC and Cmax demonstrate linearity, but with increasing doses the increase in both AUC and Cmax are slightly less than dose-proportional.
Potential for drug-drug interactions
Eravacycline and its metabolites are not inhibitors of CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6 or CYP3A4 in vitro. Eravacycline, TP-498 and TP-6208 are not inducers of CYP1A2, CYP2B6 or CYP3A4.
Eravacycline, TP-498 and TP-6208 are not inhibitors of BCRP, BSEP, OATP1B1, OATP1B3, OAT1, OAT3, OCT1, OCT2, MATE1 or MATE2-K transporters. The metabolites TP-498 and TP-6208 are not inhibitors of P-gp in vitro.
Special populations
Renal impairment
The geometric least square mean Cmax for eravacycline was increased by 8.8% for subjects with end stage renal disease (ESRD) versus healthy subjects with 90% CI -19.4, 45.2. The geometric least square mean AUC0-inf for eravacycline was decreased by 4.0% for subjects with ESRD versus healthy subjects with 90% CI -14.0, 12.3.
Hepatic impairment
The geometric mean Cmax for eravacycline was increased by 13.9%, 16.3%, and 19.7% for subjects with mild (Child-Pugh Class A), moderate (Child-Pugh Class B), and severe (Child-Pugh Class C) hepatic impairment versus healthy subjects, respectively. The geometric mean AUC0-inf for eravacycline was increased by 22.9%, 37.9%, and 110.3% for subjects with mild, moderate, and severe hepatic impairment versus healthy subjects, respectively.
Gender
In a population pharmacokinetic analysis of eravacycline, no clinically relevant differences in AUC by gender were observed for eravacycline.
Elderly (≥ 65 years)
In a population pharmacokinetic analysis of eravacycline, no clinically relevant differences in the pharmacokinetics of eravacycline were observed with respect to age.
Body weight
In a population pharmacokinetic analysis it was shown that eravacycline disposition (clearance and volume) was dependent on body weight. However, the resulting difference in exposure to eravacycline in terms of AUC does not warrant dose adjustments in the weight range studied. No data are available for patients weighing more than 137 kg. The potential influence of severe obesity on eravacycline exposure has not been studied.