Aksit D, Korkut O, Aksoz E, Gokbulut C
a Department of Pharmacology and Toxicology, Faculty of Veterinary , Balikesir University , Balikesir , Turkey.
b Department of Medical Pharmacology, Faculty of Medicine , Balikesir University , Balikesir , Turkey.
N Z Vet J. 2016 Jul;64(4):207-11. doi: 10.1080/00480169.2016.1146172. Epub 2016 Feb 24.
To investigate the plasma disposition and faecal excretion of eprinomectin (EPM) in non-lactating dairy cattle following topical and S/C administration.
Holstein dairy cows, 3.5-5 years-old, were selected 20-25 days after being dried off and were randomly allocated to receive EPM either topically (n=5) or S/C (n=5) at dose rates of 0.5 and 0.2 mg/kg bodyweight, respectively. Heparinised blood and faecal samples were collected at various times between 1 hour and 30 days after treatment, and were analysed for concentrations of EPM using high performance liquid chromatography with a fluorescence detector.
The maximum concentration of EPM in plasma (Cmax) and the time to reach Cmax were both greater after S/C administration (59.70 (SD 12.90) ng/mL and 1.30 (SD 0.27) days, respectively) than after topical administration (20.73 (SD 4.04) ng/mL and 4.40 (SD 0.89) days, respectively) (p<0.001). In addition, S/C administration resulted in greater plasma availability (area under the curve; AUC), and a shorter terminal half-life and mean residence time (295.9 (SD 61.47) ng.day/mL; 2.95 (SD 0.74) days and 4.69 (SD 1.01) days, respectively) compared with topical administration (168.2 (SD15.67) ng.day/mL; 4.63 (SD 0.32) days, and 8.23 (SD 0.57) days, respectively) (p<0.01). EPM was detected in faeces between 0.80 (SD 0.45) and 13.6 (SD 4.16) days following S/C administration, and between 1 (SD 0.5) and 20.0 (SD 3.54) days following topical administration. Subcutaneous administration resulted in greater faecal excretion than topical administration, expressed as AUC adjusted for dose (1188.9 (SD 491.64) vs. 311.5 (SD 46.90) ng.day/g; p<0.05). Maximum concentration in faeces was also higher following S/C than topical administration (223.0 (SD 63.96) vs. 99.47 (SD 43.24) ng/g; p<0.01).
Subcutaneous administration of EPM generated higher plasma concentrations and greater plasma availability compared with topical administration in non-lactating cattle. Although the S/C route provides higher faecal concentrations, the longer faecal persistence of EPM following topical administration may result in more persistent efficacy preventing establishment of incoming nematode larvae in cattle.
研究非泌乳期奶牛经皮和皮下注射伊维菌素（EPM）后的血浆处置和粪便排泄情况。
选择3.5 - 5岁的荷斯坦奶牛，在干奶后20 - 25天随机分组，分别经皮（n = 5）或皮下（n = 5）给予EPM，剂量分别为0.5和0.2 mg/kg体重。在治疗后1小时至30天的不同时间采集肝素化血液和粪便样本，使用带荧光检测器的高效液相色谱法分析EPM浓度。
皮下注射后血浆中EPM的最大浓度（Cmax）和达到Cmax的时间均高于经皮注射（分别为59.70（标准差12.90）ng/mL和1.30（标准差0.27）天），经皮注射分别为20.73（标准差4.04）ng/mL和4.40（标准差0.89）天（p < 0.001）。此外，皮下注射导致更高的血浆可用性（曲线下面积；AUC），与经皮注射相比，终末半衰期和平均驻留时间更短（分别为295.9（标准差61.47）ng·天/mL；2.95（标准差0.74）天和4.69（标准差1.01）天），经皮注射分别为168.2（标准差15.67）ng·天/mL；4.63（标准差0.32）天和8.23（标准差0.57）天（p < 0.01）。皮下注射后0.80（标准差0.45）至13.6（标准差4.16）天在粪便中检测到EPM，经皮注射后1（标准差0.5）至20.0（标准差3.54）天在粪便中检测到EPM。皮下注射导致的粪便排泄量高于经皮注射，以剂量调整后的AUC表示（1188.9（标准差491.64）对311.5（标准差46.90）ng·天/g；p < 0.05）。皮下注射后粪便中的最大浓度也高于经皮注射（223.0（标准差63.96）对99.47（标准差43.24）ng/g；p < 0.01）。
与非泌乳期奶牛经皮注射相比，皮下注射EPM产生更高的血浆浓度和更大的血浆可用性。虽然皮下注射途径粪便浓度更高，但经皮注射后EPM在粪便中的持续时间更长，可能导致预防牛体内新侵入线虫幼虫定殖的效果更持久。
