Prediction of CNS occupancy of dopamine D2 receptor based on systemic exposure and in vitro experiments

Drug Metab Pharmacokinet. 2016 Dec;31(6):395-404. doi: 10.1016/j.dmpk.2016.07.003. Epub 2016 Jul 30.

Abstract

The effect of drugs in the central nervous system (CNS) is closely related to occupancy of their target receptor. In this study, we integrated plasma concentrations, in vitro/in vivo data for receptor or protein binding, and in silico data, using a physiologically based pharmacokinetic model, to examine the predictability of receptor occupancy in humans. The occupancy of the dopamine D2 receptor and the plasma concentrations of the antipsychotic drugs quetiapine and perospirone in humans were collected from the literature or produced experimentally. Association and dissociation rate constants and unbound fractions in the serum and brain were determined in vitro/in vivo using human D2 receptor-expressing membrane fractions, human serum and mouse brain. The permeability of drugs across the blood-brain barrier was estimated based on their physicochemical properties. The effect of a metabolite of perospirone, ID-15036, was also considered. The time profiles of D2 receptor occupancy following oral dose of quetiapine and perospirone predicted were similar to the observed values. This approach could assist in the design of clinical studies for drug development and the prediction of the impact of drug-drug interactions on CNS function in clinical settings.

Keywords: Brain; Central nervous system; Dopamine D2 receptor; Human; Physiologically based pharmacokinetic model; Positron emission tomography; Receptor occupancy.

MeSH terms

  • Adult
  • Animals
  • Antipsychotic Agents / blood
  • Antipsychotic Agents / pharmacokinetics*
  • Brain / metabolism*
  • Computer Simulation
  • Dopamine D2 Receptor Antagonists / blood
  • Dopamine D2 Receptor Antagonists / metabolism
  • Dopamine D2 Receptor Antagonists / pharmacokinetics*
  • Humans
  • Isoindoles / blood
  • Isoindoles / pharmacokinetics
  • Kinetics
  • Male
  • Mice, Inbred ICR
  • Positron-Emission Tomography
  • Quetiapine Fumarate / blood
  • Quetiapine Fumarate / pharmacokinetics
  • Raclopride / metabolism
  • Receptors, Dopamine D2 / metabolism*
  • Thiazoles / blood
  • Thiazoles / pharmacokinetics
  • Young Adult

Substances

  • Antipsychotic Agents
  • DRD2 protein, human
  • DRD2 protein, mouse
  • Dopamine D2 Receptor Antagonists
  • Isoindoles
  • Receptors, Dopamine D2
  • Thiazoles
  • Quetiapine Fumarate
  • Raclopride
  • perospirone