Evaluation of efficacy and pharmacokinetics of novel fluralaner tablet formulation (WellPet™) in dogs.

Abstract

The increasing use of isoxazolines represents a major trend in the control of ectoparasites in companion animals. WellPet™ (Ourofino Saúde Animal Ltd., Brazil) is a newly developed, highly palatable oral tablet containing fluralaner. This study aimed to characterize the pharmacokinetic profile of this formulation and to evaluate its efficacy against fleas and ticks for up to 45 days following administration. Two complementary studies were conducted. In the pharmacokinetic study, WellPet™ was administered orally to 12 healthy dogs at a dose range of 10 to 22.5 mg/kg, and plasma fluralaner concentrations were measured at predefined time points up to 49 days post-treatment, yielding a peak plasma concentration (Cmax) of 3,763 μg/L, a time to maximum concentration (Tmax) of 2.0 days, an area under the concentration-time curve (AUCtotal) of 53,342.48 μg·day/L, and an elimination half-life (t½) of 17.88 days. In the efficacy study, 12 dogs were randomly allocated into two groups: six animals treated with WellPet™ and six assigned to a negative control group, and were experimentally infested with fleas () and ticks () at scheduled time points. Post-treatment evaluations demonstrated sustained efficacy above regulatory thresholds, with tick efficacy remaining at 100% from Day 1 to Day 28 and exceeding 97% throughout the 45-day observation period (99.5% on Day 35, 98.1% on Day 42, and 97.98% on Day 45), and flea control reaching 100% efficacy on all post-treatment evaluation days. These findings demonstrate that the proposed label dose of 10 to 22.5 mg/kg achieves plasma concentrations sufficient to support robust and sustained clinical efficacy for at least 45 days, and that the integration of pharmacokinetic and efficacy data provides a mechanistic basis for the observed parasitological outcomes. This optimized 45-day retreatment interval represents a safe and effective alternative to conventional fluralaner regimens, offering reduced dosing frequency, improved owner compliance, and strategic advantages for ectoparasite control and companion animal health management.