AgResearch Grassland, Private Bag 11008, Tennent Drive, Palmerston North, 4442, New Zealand.
AgResearch Grassland, Private Bag 11008, Tennent Drive, Palmerston North, 4442, New Zealand.
Int J Parasitol Drugs Drug Resist. 2020 Dec;14:152-158. doi: 10.1016/j.ijpddr.2020.10.006. Epub 2020 Oct 20.
An animal trial was conducted to measure the concentrations of ivermectin occurring in abomasal and small intestinal contents and mucosa, and in the target parasites (Ostertagia ostertagi and Cooperia oncophora) following administration by subcutaneous, oral and pour-on routes. Twenty-five steers were infected with ivermectin-resistant isolates of O. ostertagi and C. oncophora and following patency randomly allocated to 3 treatment groups of 7 and 1 untreated control group of four. On day 0, animals in the treatment groups were administered ivermectin via the oral, injectable or pour-on routes. On days 1, 2, 3, 4, 5, 6 and 8, blood samples were collected from all live animals, one animal from each treatment group was euthanised and the abomasum and small intestine recovered. Control animals were euthanised on each of days 4, 5, 6 and 8. Samples of gastrointestinal tract organs, their contents, mucosa and parasites were collected and assayed for ivermectin concentration using HPLC. The highest plasma concentrations occurred following subcutaneous administration. In the gastrointestinal contents the highest levels occurred following oral administration, although one high value occurred following pour-on administration, which was attributed to self-licking by the treated animal. The lowest GI content levels followed subcutaneous injection. Ivermectin concentrations in the gastrointestinal mucosa were highest following subcutaneous injection. Drug levels in the abomasal parasite O. ostertagi were most closely correlated with levels in the abomasal mucosa whereas levels in the intestinal C. oncophora were most closely correlated with those in the intestinal contents. Thus, the maximun levels of drug reached C. oncophora in the small intestine following oral administration. In contrast, the highest levels of ivermectin in O. ostertagi followed subcutaneous injection. Therefore, route of administration is likely to influence the exposure to ivermectin for different parasite species.
进行了一项动物试验，以测量皮下、口服和涂敷给药后，伊维菌素在皱胃和小肠内容物和黏膜中以及目标寄生虫（Ostertagia ostertagi 和 Cooperia oncophora）中的浓度。25 头小公牛感染了伊维菌素耐药的 O. ostertagi 和 C. oncophora 分离株，在通畅后随机分为 3 个治疗组（每组 7 头）和 1 个未治疗对照组（4 头）。在第 0 天，给治疗组动物口服、注射或涂敷伊维菌素。在第 1、2、3、4、5、6 和 8 天，从所有活动物采集血液样本，从每个治疗组中采集一头动物进行安乐死，并回收皱胃和小肠。对照动物在第 4、5、6 和 8 天分别安乐死。采集胃肠道器官、内容物、黏膜和寄生虫样本，使用 HPLC 测定伊维菌素浓度。皮下给药后出现最高的血浆浓度。在胃肠道内容物中，口服给药后出现最高水平，尽管涂敷给药后出现一个高值，这归因于受治动物的自舔。皮下注射后胃肠道内容物中的水平最低。皮下注射后胃肠道黏膜中的伊维菌素浓度最高。皱胃寄生虫 O. ostertagi 中的药物水平与皱胃黏膜中的水平最密切相关，而肠道 C. oncophora 中的药物水平与肠道内容物中的水平最密切相关。因此，口服给药后，肠道 C. oncophora 在小肠中达到药物的最大水平。相比之下，O. ostertagi 中的伊维菌素水平最高，随后是皮下注射。因此，给药途径可能会影响不同寄生虫物种对伊维菌素的暴露。
