Safety, pharmacokinetics, relative bioavailability and dose linearity of
four formulations of emodepside in healthy male subjects
Abstract
Aims: Emodepside is an anthelmintic, originally developed for veterinary
use. We investigated the safety, pharmacokinetics, relative
bioavailability and dose linearity of four oral formulations of
emodepside in healthy male subjects. Methods: Three randomised,
parallel‐group, controlled, Phase I studies were conducted using various
oral formulations, involving 79 subjects in ten cohorts in the
single-ascending-dose study, 24 subjects in three ascending-dose cohorts
in the multiple-ascending-dose study and 77 subjects in seven different
cohorts in the relative bioavailability study. Pharmacokinetics and
safety assessments were performed up to 21, 30 and 7 days, respectively.
Results: As a liquid service formulation, emodepside was rapidly
absorbed under fasting conditions, with dose-proportional increases in
plasma concentrations at doses from 1 mg to 40 mg. The half-life during
the first 24 hours after dosing was around 11 hours, followed by a
terminal elimination half-life > 500 hours. Emodepside was
less bioavailable in the fed state. The rate of absorption was slower
and Cmax was lower with the amorphous solid dispersion tablets compared
to the liquid service formulation. Emodepside was well tolerated overall
with no major safety concerns. Conclusion: These Phase I studies with
various dosage forms revealed a pharmacokinetic profile suggesting good
tissue distribution of emodepside and a long terminal half‐life. A 15 mg
dose with the gastrosoluble tablet is predicted to provide exposure that
will achieve the target concentration for clinical efficacy. These data
enabled us to select a field-adapted tablet formulation that will open
the way for further clinical development of emodepside in individuals
with onchocerchiasis.