title: Ivermectin disposition kinetics after subcutaneous and intramuscular administration of an oil-based formulation to cattle.
abstract: Slight differences in formulation may change the plasma kinetics and ecto-endoparasiticide activity of endectocide compounds. This work reports on the disposition kinetics and plasma availability of ivermectin (IVM) after subcutaneous (SC) and intramuscular (IM) administration as an oil-based formulation to cattle. Parasite-free Aberdeen Angus calves (n = 24; 240-280 kg) were divided into three groups (n = 8) and treated (200 microg/kg) with either an IVM oil-based pharmaceutical preparation (IVM-TEST formulation) (Bayer Argentina S.A.) given by subcutaneous (Group A) and intramuscular (Group B) injections or the IVM-CONTROL (non-aqueous formulation) (Ivomec, MSD Agvet) subcutaneously administered (Group C). Blood samples were taken over 35 days post-treatment and the recovered plasma was extracted and analyzed by HPLC using fluorescence detection. IVM was detected in plasma between 12 h and 35 days post-administration of IVM-TEST (SC and IM injections) and IVM-CONTROL formulations. Prolonged IVM absorption half-life (p < 0.05) and delayed peak plasma concentration (p < 0.001) were obtained following the SC administration of the IVM-TEST compared to the IVM-CONTROL formulation. No differences in total plasma availability were observed among treatments. However, the plasma residence time and elimination half-life of IVM were significantly longer after injection of the IVM-TEST formulation. IVM plasma concentrations were above 0.5 ng/ml for 20.6 (CONTROL) and 27.5 days (IVM-TEST SC), respectively (p < 0.05). The modified kinetic behaviour of IVM obtained after the administration of the novel oil-based formulation examined in this trial, compared to the standard preparation, may positively impact on its strategic use in cattle.
authors.affiliation: Departamento de Fisiopatología, Facultad de Ciencias Veterinarias, Universidad Nacional del Centro, Campus Universitario, Tandil, Argentina.
authors.forename: A
authors.initials: A
authors.lastname: Lifschitz
authors.forename: G
authors.initials: G
authors.lastname: Virkel
authors.forename: A
authors.initials: A
authors.lastname: Pis
authors.forename: F
authors.initials: F
authors.lastname: Imperiale
authors.forename: S
authors.initials: S
authors.lastname: Sanchez
authors.forename: L
authors.initials: L
authors.lastname: Alvarez
authors.forename: R
authors.initials: R
authors.lastname: Kujanek
authors.forename: C
authors.initials: C
authors.lastname: Lanusse
mesh_terms: D000818:Animals; D000871:Anthelmintics / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use; D019540:Area Under Curve; D002417:Cattle; D002418:Cattle Diseases / Q000188:drug therapy* / Q000517:prevention & control; D002851:Chromatography, High Pressure Liquid / Q000662:veterinary; D004337:Drug Carriers; D006207:Half-Life; D007273:Injections, Intramuscular / Q000662:veterinary; D007279:Injections, Subcutaneous / Q000662:veterinary; D007559:Ivermectin / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use; D008297:Male; D013050:Spectrometry, Fluorescence / Q000662:veterinary
chemical_list: D000871:Anthelmintics; D004337:Drug Carriers; D007559:Ivermectin