Cardamone M, Lee R P, Lucas J C, Birks D V, O'Donoghue M, Lofthouse S A, Brandon M R
Centre for Animal Biotechnology, School of Veterinary Science, University of Melbourne, Parkville, Victoria, Australia.
J Control Release. 1998 Jan 23;51(1):73-83. doi: 10.1016/s0168-3659(97)00160-0.
A solid formulation of a potent anthelmintic macrocyclic lactone, moxidectin, was administered using a non-degradable delivery device to discharge the agent into the subcutaneous tissues of sheep. In vivo release was monitored in sheep indirectly using faecal egg counts. Using a dose of 0.2 mg moxidectin/kg body weight when applied in the form of a solid pellet, protection of sheep against Haemonchus contortus challenge was conferred to a level greater than that of sheep which received Cydectin, the commercial liquid injectable form delivered at the same dosage. The anthelmintic efficacy of the solid formulation was assessed at four dosage levels in sheep and it was demonstrated that the dosage of anthelmintic agent could be reduced to 1/6 of the present recommended injectable dose. When two pellets containing the recommended dose of moxidectin were loaded into a non-degradable delivery device, the period of H. contortus control was extended from 42 to 183 days. Antibody levels of sheep receiving repeated infections of H. contortus L3 larvae and treated with moxidectin-loaded devices were reduced significantly compared to the levels observed in sheep treated with Cydectin (p < 0.0005). This implies that the group treated with the moxidectin-loaded devices was exposed to a reduced antigenic load compared to sheep treated with placebo devices, and sheep treated with Cydectin. The antibody levels generated in the sheep treated with placebo devices were no different to those treated with Cydectin. Application of this sustained release device may allow the control of nematode diseases in livestock throughout an entire season with a single administration.
强效驱虫大环内酯类药物莫昔克丁的固体剂型，通过不可降解给药装置给药，将药物释放到绵羊的皮下组织中。在绵羊体内，通过粪便虫卵计数间接监测药物释放情况。以固体颗粒形式给药时，使用0.2毫克莫昔克丁/千克体重的剂量，对绵羊的保护作用可抵御捻转血矛线虫的攻击，其保护水平高于接受相同剂量商业液体注射剂型“赛得菌素”的绵羊。在绵羊身上评估了该固体剂型在四个剂量水平下的驱虫效果，结果表明驱虫剂的剂量可降至目前推荐注射剂量的1/6。当将两个含有推荐剂量莫昔克丁的颗粒装入不可降解给药装置时，对捻转血矛线虫的控制期从42天延长至183天。与接受“赛得菌素”治疗的绵羊相比，接受捻转血矛线虫L3幼虫反复感染并使用装有莫昔克丁的装置治疗的绵羊抗体水平显著降低（p < 0.0005）。这意味着与接受安慰剂装置治疗的绵羊以及接受“赛得菌素”治疗的绵羊相比，使用装有莫昔克丁的装置治疗的组接触到的抗原负荷降低。接受安慰剂装置治疗的绵羊产生的抗体水平与接受“赛得菌素”治疗的绵羊无异。应用这种缓释装置单次给药可能使整个季节的家畜线虫病得到控制。
