Pharmacokinetics of Levamisole After a Single 20 mg/kg Intravenous, Intramuscular, or Subcutaneous Dose in Chukar Partridges (Alectoris chukar)

The pharmacokinetic features of levamisole were assessed in chukar partridges (Alectoris chukar) following intravenous (IV), intramuscular (IM), and subcutaneous (SC) administrations. The investigation included nine male partridges and a crossover pharmacokinetic design. Levamisole was administered to partridges at a dose of 20 mg/kg via IV, IM, and SC routes. Blood samples were collected at time points of 0, 0.25, 0.50, 1, 1.5, 2, 3, 4, 6, 8, 10, 12, 18, and 24 h after administrations. Plasma concentrations of levamisole were quantified by high-performance liquid chromatography (HPLC) and evaluated using a non-compartmental analysis. The elimination half-life was 1.92, 2.94, and 2.97 h for IV, IM, and SC administration, respectively. The IV injection for levamisole showed the volume of distribution at a steady state of 1.91 L/kg and total clearance of 0.73 L/h/kg. The peak plasma concentration (Cmax) for IM and SC routes of levamisole was 5.32 and 4.65 μg/mL at 0.25 h, respectively. The absolute bioavailability was 66.16% for the IM route and 58.48% for the SC route. The study findings reveal that levamisole administered via IM and SC routes exhibit comparable pharmacokinetic profiles, with both routes achieving bioavailability exceeding 50%. However, the significant adverse effects (muscle tremors, hyperexcitability, and increased respiratory rate) associated with IV administration underscore the need for caution and support the preference for IM and SC routes, which offer better safety profiles for bird anthelmintic treatments.