title: Plasma and milk kinetics of eprinomectin following topical or oral administration to lactating Chinese Holstein cows.
abstract: Chinese Holstein, bred by mating the Holstein-Friesian to Chinese Yellow Cattle, is a major dairy cattle breed in China. Eprinomectin is widely used in the treatment of nematode and ectoparasite infections in lactating cattle. The pharmacokinetics of eprinomectin in the plasma and milk were determined in Chinese Holstein cows following topical (at 0.5 mg kg(-1)) or oral (at 0.2 mg kg(-1)) administration. For topical administration, the concentrations of eprinomectin in plasma reached peak values (C(max)) of 16.16 ± 6.02 ng ml(-1) at 3.20 ± 1.30 days (T(max)). In milk, the C(max) values of 2.28 ± 0.85 ng ml(-1) were obtained at 3.48 ± 0.65 days. The MRT values were 5.00 ± 0.96 days for plasma and 4.65 ± 0.60 days for milk. The AUC values were 91.00 ± 25.32 ng d ml(-1) for plasma and 10.53 ± 1.55 ng d ml(-1) for milk. The ratio of AUC milk/plasma was 0.124 ± 0.041. Significant differences were found in C(max) and AUC of eprinomectin in plasma between Chinese Holstein and Prim Holstein following topical administration. It was probably due to the lower storage of body fat in Chinese Holstein than in Prim Holstein. For oral administration, the concentrations of eprinomectin reach peak values of 30.02 ± 5.73 ng ml(-1) at 1.60 ± 0.55 days in plasma and 3.14 ± 0.88 ng ml(-1) at 1.40 ± 0.27 days in milk. The MRT values for plasma and milk were 3.00 ± 0.46 and 3.18 ± 0.55 days, respectively. The AUC values were 98.46 ± 24.75 ng d ml(-1) for plasma and 10.42 ± 4.22 ng d ml(-1) for milk. The ratio of AUC milk/plasma was 0.104 ± 0.022. Compared with the topical administration, a significantly shorter MRT of eprinomectin in plasma was obtained following oral administration, which would shorten residue time of this compound in faeces and reduce its ecotoxicological effect. The low exposure of eprinomectin in milk would favor the use of eprinomectin in lactating Chinese Holstein for topical or oral administration.
authors.affiliation: Key Laboratory of Development and Evaluation of the Chemical and Herbal Drugs for Animal Use, College of Veterinary Medicine, China Agricultural University, Yuanmingyuan West Road No. 2, Haidian District, 100193 Beijing, China.
authors.forename: Huiqiang
authors.initials: H
authors.lastname: Wen
authors.forename: Baoliang
authors.initials: B
authors.lastname: Pan
authors.forename: Yuwan
authors.initials: Y
authors.lastname: Wang
authors.forename: Fangfei
authors.initials: F
authors.lastname: Wang
authors.forename: Zhenzhong
authors.initials: Z
authors.lastname: Yang
authors.forename: Ming
authors.initials: M
authors.lastname: Wang
mesh_terms: D000284:Administration, Oral; D000287:Administration, Topical; D000818:Animals; D002417:Cattle; D002681:China; D005260:Female; D007559:Ivermectin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics; D007774:Lactation; D008892:Milk / Q000737:chemistry*
chemical_list: D007559:Ivermectin; C101434:eprinomectin