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Ivermectin (3.15%) long-acting formulations in cattle: absorption pattern and pharmacokinetic considerations
A Lifschitz1, G Virkel, M Ballent
1Laboratorio de Farmacología, Departamento de Fisiopatología, Facultad de Ciencias Veterinarias, Universidad Nacional del Centro, Campus Universitario, (7000) Tandil, Buenos Aires, Argentina. adrianl@vet.unicen.edu.ar
Veterinary Parasitology
|May 26, 2007
Summary
Newer long-acting ivermectin (IVM-LA) formulations for cattle showed varied absorption profiles compared to the classic IVM 1% preparation. IVM-LA (A) provided longer detectable plasma concentrations than IVM-LA (B).
Area of Science:
- Veterinary Pharmacology
- Drug Delivery Systems
- Pharmacokinetics
Background:
- Ivermectin (IVM) is a critical antiparasitic in veterinary medicine, with formulation significantly impacting its absorption and systemic availability.
- The development of long-acting (LA) ivermectin formulations aims to extend its persistent efficacy in cattle.
- Recent introduction of 3.15% IVM-LA preparations necessitates comparative pharmacokinetic evaluation against established formulations.
Purpose of the Study:
- To comparatively evaluate the absorption patterns and plasma concentration profiles of ivermectin (IVM) after subcutaneous administration in cattle.
- To assess the pharmacokinetic differences between a classic 1% IVM formulation and two distinct 3.15% IVM-LA preparations.
- To characterize the kinetic behavior of novel long-acting formulations at an elevated dose (630 microg/kg) in cattle.
Main Methods:
- Twenty-eight Holstein heifers were divided into four groups and received subcutaneous injections of either 1% IVM (200 or 630 microg/kg) or one of two 3.15% IVM-LA preparations (630 microg/kg).
- Plasma samples were collected over 90 days post-treatment.
- Ivermectin concentrations were quantified using High-Performance Liquid Chromatography (HPLC) with fluorescence detection.
Main Results:
- No significant differences in IVM plasma concentration persistence were observed between 1% IVM administered at 200 and 630 microg/kg.
- The 1% IVM formulation at 630 microg/kg resulted in higher peak plasma concentrations (Cmax) and shorter mean residence time (MRT) compared to both IVM-LA preparations.
- IVM-LA (A) exhibited a more prolonged absorption process, leading to longer detectable IVM plasma concentrations compared to IVM-LA (B).
Conclusions:
- Different IVM formulations, particularly long-acting preparations, demonstrate distinct absorption kinetics and plasma concentration profiles in cattle.
- The observed variations in Cmax and long-term plasma levels between IVM-LA (A) and IVM-LA (B) warrant further investigation into their parasitological implications.
- Characterizing the absorption and kinetic behavior of these novel LA formulations at higher doses provides valuable data for veterinary pharmaceutical applications.
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