title: Linearity of eprinomectin pharmacokinetics in lactating dairy sheep following pour-on administration: excretion in milk and exposure of suckling lambs.
abstract: Pharmacokinetics of eprinomectin (EPR) were studied in blood plasma and milk in two groups of six Istrian Pramenka dairy sheep and their suckling lambs following pour-on administration of EPR to ewes at dose levels of 0.5 and 1mg/kg. Maximum concentration in plasma was 2.22 and 5.25 microg/l, and AUC was 13.6 and 33.7 microg day/l for the 0.5 and 1.0mg/kg dose, respectively. These results indicate that drug exposure with a dose of 0.5mg/kg, which is commonly used in cattle, may be subtherapeutic. The concentration time course in milk paralleled plasma concentrations. In the dose range studied, linear pharmacokinetics of EPR were demonstrated. Milk-to-plasma AUC ratio was 0.79+/-0.12 and 1.12+/-0.43; the fraction of dose recovered in milk was 0.037+/-0.011 and 0.058+/-0.027% for the low and high dose, respectively. Maximum residual levels in milk were below the maximum acceptable level of 20 microg/kg; however, EPR was detected in all samples investigated. Despite low permeability in milk, AUC in plasma of suckling lambs was between 20 and 30% of the AUC in plasma of ewes.
authors.affiliation: Veterinary Faculty of University of Ljubljana, Gerbiceva 60, SI-1000 Ljubljana, Slovenia. lenahodoscek@gmail.com
authors.forename: Lena
authors.initials: L
authors.lastname: Hodoscek
authors.forename: Iztok
authors.initials: I
authors.lastname: Grabnar
authors.forename: Luka
authors.initials: L
authors.lastname: Milcinski
authors.forename: Adica
authors.initials: A
authors.lastname: Süssinger
authors.forename: Nevenka Kozuh
authors.initials: NK
authors.lastname: Erzen
authors.forename: Tomaz
authors.initials: T
authors.lastname: Zadnik
authors.forename: Milan
authors.initials: M
authors.lastname: Pogacnik
authors.forename: Vesna
authors.initials: V
authors.lastname: Cerkvenik-Flajs
mesh_terms: D000287:Administration, Topical; D000818:Animals; D000833:Animals, Suckling; D000871:Anthelmintics / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D005260:Female; D007559:Ivermectin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics; D007774:Lactation; D008892:Milk / Q000737:chemistry*; D012756:Sheep / Q000097:blood*
chemical_list: D000871:Anthelmintics; D007559:Ivermectin; C101434:eprinomectin