Pharmacokinetics and anthelmintic efficacy of topical eprinomectin in goats prevented from grooming

Abstract

Pharmacokinetics and anthelmintic activity of topical eprinomectin in goats prevented from physical contact to others and self-grooming were studied. Sixteen approximately 7 months old male castrated German White Noble goats harbouring induced infections of gastrointestinal nematode parasites were included in the study. They were blocked based on pre-treatment body weight (range 22.4 to 36.4 kg) and then randomly allocated to the untreated control group or the group treated with topical 0.5% w/v eprinomectin (EPRINEX Pour-on, Merial) at 1 mg/kg body weight. Plasma samples were collected prior to and at intervals up to 14 days following treatment and analyzed to determine the concentrations of eprinomectin (B1a component). Parasites were recovered, identified, and counted following necropsy 14 days after treatment. Goats treated with topical eprinomectin had significantly fewer (≥99% reduction, p < 0.01) adult Cooperia curticei, Haemonchus contortus, Nematodirus battus, Oesophagostomum venulosum, Ostertagia circumcincta, and Trichostrongylus colubriformis than the untreated controls. Basic pharmacokinetic parameters for eprinomectin B1a were AUCinfinity, 37.1 ± 15.2 day ng/mL; T½, 5.11 ± 2.83 days; and Cmax, 5.93 ± 1.87 ng/mL; individual maximal concentrations were observed 1 or 2 days after treatment. Results of this study indicate that oral ingestion is not required to achieve adequate exposure for excellent anthelmintic efficacy following topical administration of eprinomectin at 1 mg/kg body weight to goats.

Eprinomectin pour-on (EPRINEX® Pour-on, Merial): efficacy against gastrointestinal and pulmonary nematodes and pharmacokinetics in sheep

“…In addition, there is also indication of efficacy of topical 0.5% w / v eprinomectin against Oestrus ovis nasal bot infestation [16, 17]. Overall, the therapeutic efficacy demonstrated in the present studies in sheep was very similar to the array of nematode parasites effectively treated by the administration of topical 0.5% w / v eprinomectin at 1 mg per kg body weight to goats [39, 40]. …”

“…40], T max appears to occur later in sheep, indicating slower absorption possibly due to the difference of the structure of the skin/hair coat characteristics between the two species. Overall, similar pharmacokinetic profiles were demonstrated for topical 0.5% w / v eprinomectin in sheep and goats which translate to a similar spectrum of anthelmintic activity in sheep (these Studies 1, 2 and 3) and goats [39, 40, 49]. …”

Evaluation of the pharmacokinetics and efficacy of transdermal flunixin for pain mitigation following castration in goats

“…Oral, intramuscular, and intravenous pharmacokinetic data have also been reported for adult goats suggesting that the intravenous dose of 2.2 mg/kg is applicable for goats ( Konigsson et al, 2003 ). Other pour-on products such as topical eprinomectin have reported lower bioavailability in goats than in cattle ( Rehbein et al, 2014 ). Eprinomectin has a much lower plasma concentration in goats compared to cattle designated by lower C max and AUC indicating the recommended bovine dosage may not be adequate in caprine ( Alvinerie et al, 1999 ).…”

Evaluation of the pour-on administration of eprinomectin on milk yield and somatic cell counts in dairy ewes naturally infected with gastrointestinal nematodes

“…Efficacy studies, conducted in sheep ( Hamel et al, 2017 , Hamel et al, 2018 ), goats ( Rehbein et al, 2014 ) and cattle ( Rehbein et al, 2012 ), reported high anthelmintic efficacy of pour-on formulation of eprinomectin, at the recommended dosage, for each of the forementioned animal species. In our study, the efficacy of topically administered eprinomectin was also high (>90%) for the first 42 days post treatment.…”

“…The anthelmintic efficacy of pour-on eprinomectin has been studied in sheep ( Hamel et al, 2017 , Hamel et al, 2018 ), goats ( Rehbein et al, 2014 ) and cattle ( Rehbein et al, 2012 ). However, there is no research establishing the association between treatment of nematode-infected dairy sheep with eprinomectin and their milk yield or somatic cell counts (SCC) in milk.…”