Population Pharmacokinetics of Apomorphine in Patients with Parkinson’s Disease

The population pharmacokinetic parameters of apomorphine, a potent dopamine agonist used in the treatment of on-off fluctuations in 8 Parkinsonian patients, were calculated after subcutaneous and intranasal administration. Compared with the ‘traditional’ standard 2-stage method or naïve pooling, the nonparametric expectation maximization method (NPEM2) program from the USC*PACK collection provides similar results, but more information about the population under investigation. Two available software packages for therapeutic drug monitoring were used: USC*PACK and MW/PHARM. We compared the calculated parameters: elimination constant (kel), distribution volume (Vslope), absorption constant (ka) and bioavailability. Small differences were observed in the following population pharmacokinetic data: Subcutaneous administration (n=8): Vslope=1.89 ±0.97 L/kg, kel=1.46 ±0.63 hour−1, ka=10.5 ±7.6 hour−1. Intranasal administration (n=6): Vslope=1.68 ±0.71 L/kg, kel=1.41 ±0.58 hour−1, ka=9.45 ±4.97 hour−1, bioavailability 1.32 ±0.81.