Pharmacokinetics of a novel spot-on formulation of praziquantel for dogs

Dogs were administered PZQ (14.5 mg/kg PZQ, from a solution of 100 mg/ml). Blood samples were drawn before treatment onset and at the following time points after PZQ administration: 1, 2, 4, 6, 12, 24 and 48 h. PZQ plasma concentration was determined by ultra-high performance liquid chromatography (UPLC) coupled to tandem mass spectrometry (MS/MS). Observed maximum concentration (Cmax), area under the concentration-time curve from the time of drug administration to infinity (AUCinf) and time to maximum concentration (Tmax) were calculated for each animal, and mean ± SD for each parameter was obtained. Results were as follows: Cmax = 56.0 ± 15 ng/ml; AUCinf = 910.2 ± 220 ng* h/ml, Tmax = 5.0 ± 1.1 h. This is the first study to provide pharmacokinetic data of a praziquantel spot-on formulation for dogs.