Studies in early clinical development
1. Bioavailability (BA) / Bioequivalence (BE) studies
The objectives of bioavailability studies are to evaluate the rate and extent of absorption of a medicine. This is assessed measuring the maximum concentration (Cmax) and time of maximum concentration (Tmax) to evaluate the rate of absorption and area under the curve (AUC) for the extent of absorption.
The same applies to bioequivalence studies but in this case these values are compared with those of a reference formulation.
Bioavailability studies are typically run as crossover, randomised, single dose studies in healthy participants. Researchers measure blood/plasma concentrations of the parent drug and major active metabolites.
Bioequivalence studies are typically run as crossover, randomised studies in fasted healthy participants given single doses of test & reference products administered at the same doses. Researchers measure blood/plasma concentration of parent medicine only.
In order for a medicine to be bioequivalent it must fulfil set criteria.
The information gained from bioavailability and bioequivalent studies:
- Absolute bioavailability of medicine from a formulation
- Relative bioavailability (formulation test vs. formulation reference)
- Bioequivalence (no significant difference in bioavailability) of test vs. reference