Long half-life and prolonged-release dopamine receptor agonists: a review of ropinirole prolonged-release studies.

Our review summarizes the five main studies conducted to evaluate the efficacy and pharmacokinetics of ropinirole prolonged release (PR) in Parkinson's disease (PD). The PR formulation was developed with Geomatrix coating technology in order to obtain constant pharmacokinetics throughout 24 hours. The areas under the curve were not significantly different from those observed with similar doses of ropinirole immediate-release (IR) formulation, administered 3 times a day, but concentration fluctuations were less for ropinirole PR (2-fold vs 5-fold). The efficacy study of the PR versus IR formulations showed non-inferiority of the PR formulation, similar tolerability and feasibility of overnight switches, and indicated that the optimal doses of ropinirole in patients with de novo PD is in the range of 8-12 mg/day. The efficacy study in PD patients with motor fluctuations treated with L-dopa showed that adding ropinirole PR significantly reduced "off" time and increased "on" time in comparison with placebo. The study with ropinirole as an add-on to L-dopa showed a reduced incidence of dyskinesias.