title: Pharmacokinetics of an extended-release formulation of eprinomectin in healthy adult alpacas and its use in alpacas confirmed with mange.
abstract: The study objective was to determine the pharmacokinetics and clinical effects of an extended-release 5% eprinomectin formulation (Longrange®) following subcutaneous (s.c.) injection in healthy (n = 6) and mange-infected (n = 4) adult alpacas. High-performance liquid chromatography was used to analyze plasma samples obtained at regular intervals for 161 days following a single 5 mg/kg injection s.c. in healthy alpacas, and for 5 days following each dose (3 treatments, 2 months apart) in mange-affected animals. Skin scrapings and biopsies were performed pre- and post-treatment at two comparable sites in alpacas with mange. Four alpacas served as healthy controls. Eprinomectin plasma concentrations showed a biphasic peak (CMAX-1: 5.72 ± 3.25 ng/mL; CMAX-2: 6.06 ± 2.47 ng/mL) in all animals at 3.88 ± 5.16 days and 77 ± 12.52 days, respectively. Eprinomectin plasma concentrations remained above 1.27 ± 0.96 ng/mL for up to 120 days. Hematocrit (35.8 vs. 31.3%, P < 0.003) and albumin (3.5 vs. 2.8 g/dL P < 0.006) reduced significantly over 6 months in multidose animals, while fecal egg counts did not differ between groups. Self-limiting injection site reactions occurred in 9 of 10 animals. Pre- and post-treatment skin biopsies showed reduced hyperkeratosis, but increased fibrosis, with 1 of 4 alpacas remaining positive on skin scraping for mange. In conclusion, alpacas require a higher eprinomectin dose (5.0 mg/kg s.c.) than cattle, to reach comparable plasma concentrations.
authors.affiliation: Cummings School of Veterinary Medicine at Tufts Universtity, North Grafton, MA, USA.
authors.forename: J
authors.initials: J
authors.lastname: Pollock
authors.affiliation: Cummings School of Veterinary Medicine at Tufts Universtity, North Grafton, MA, USA.
authors.forename: D
authors.initials: D
authors.lastname: Bedenice
authors.affiliation: Cummings School of Veterinary Medicine at Tufts Universtity, North Grafton, MA, USA.
authors.forename: S H
authors.initials: SH
authors.lastname: Jennings
authors.affiliation: Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, St Raleigh, NC, USA.
authors.forename: M G
authors.initials: MG
authors.lastname: Papich
mesh_terms: D000818:Animals; D019540:Area Under Curve; D002161:Camelids, New World / Q000097:blood*; D003692:Delayed-Action Preparations; D005243:Feces / Q000469:parasitology; D005260:Female; D006207:Half-Life; D007306:Insecticides / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology* / Q000627:therapeutic use; D007559:Ivermectin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics / Q000627:therapeutic use; D008297:Male; D008924:Mite Infestations / Q000188:drug therapy / Q000662:veterinary*; D010270:Parasite Egg Count
chemical_list: D003692:Delayed-Action Preparations; D007306:Insecticides; D007559:Ivermectin; C101434:eprinomectin