Pharmacokinetics of opicapone, a third-generation COMT inhibitor, after single and multiple oral administration: A comparative study in the rat

- Opicapone is relatively rapid absorbed after oral administration to rats.
- Systemic exposure to opicapone increases approximately in a dose-proportional manner.
- Opicapone and BIA 9-1079 show a small systemic accumulation after multiple-dosing.

Opicapone is a novel potent, reversible and purely peripheral catechol-O-methyltransferase inhibitor that has been developed to be used as an adjunct to levodopa/aromatic L-amino acid decarboxylase inhibitor therapy for Parkinson's disease. Thus, this study aimed to compare the plasma pharmacokinetics of opicapone and its active metabolite (BIA 9-1079) after the administration of single and multiple oral doses to rats. Wistar rats (n = 8 per group) were orally treated with single (30, 60 or 90 mg/kg) or multiple (30 mg/kg once-daily for seven consecutive days) oral doses of opicapone. Blood samples were collected up to 24 h post-dosing through a cannula introduced in the tail vein of rats. After quantifying opicapone and BIA 9-1079 in plasma, a non-compartmental pharmacokinetic analysis was performed. Opicapone was quickly absorbed (time to reach the maximum plasma concentration ≤ 2 h) in both dosage regimens and the extent of systemic exposure to opicapone increased approximately in a dose-proportional manner after single-dosing within the studied dose range (30-90 mg/kg). Opicapone and BIA 9-1079 showed a relatively short plasma elimination half-life (1.58-4.50 h) and a small systemic accumulation after multiple-dosing. Hence, no pharmacokinetic concerns are expected when opicapone is administered with a once-daily dosing regimen.

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