Planning and Evaluation of Bioequivalence Studies of Drugs with Nonlinear Pharmacokinetics

A bioequivalence (BE) study is one of the key stages of investigations required for the registration of oral generic drugs. The planning of this type of study is determined by many factors, including the linearity of the pharmacokinetics of the active substance. The choice of the drug dose for a BE study will depend on this property in registering several drug strengths. Regulatory requirements for planning BE studies of drugs with non-linear pharmacokinetics are considered using atazanavir and valaciclovir as examples. An analysis of protocols and reports of BE studies received by the SCEEMP according to the State Drug Registry and open published data on BE revealed differences in both the tested drug dosages and the number of tests performed. All characteristics of the given active substance, available literature data, international experience, and current regulatory requirements should be taken into account in planning and evaluating BE studies of drugs with non-linear pharmacokinetics.