Cunningham Craig P, Brown Jenaay M, Jacobson Glenn A, Brandon Malcolm R, Martinod Serge R
Smart Drug Systems Inc, Ste 102, 181 S Broad St, Pawcatuck, CT 06379, USA.
Am J Vet Res. 2006 Sep;67(9):1564-9. doi: 10.2460/ajvr.67.9.1564.
To evaluate use of covered-rod (CR) silicone implants containing ivermectin for long-term prevention of infection with Dirofilaria immitisin dogs.
145 adult male and female dogs.
Dogs received implants of different sizes, and ivermectin concentrations and serum ivermectin concentrations were monitored for 16, 57, and 56 weeks, respectively, in 3 preclinical dose selection studies. Ability of implants to prevent infection with D immitis was evaluated in 2 further studies; dogs were challenged with 50 infective third-stage larvae 52 weeks after implant administration and necropsied 145 days after challenge, and the total number of adult heartworms was counted. A field study was then undertaken in which client-owned dogs received an implant and plasma samples were collected at intervals until week 52 for ivermectin analysis and heartworm antigen determination.
Use of the implants resulted in maintenance of an ivermectin concentration > or = 0.2 ng/mL for 12 months. In challenge studies, no treated dogs had adult heartworms, in contrast to untreated dogs, which all had adult heartworms at necropsy. In the field study, dogs treated with an implant had negative results of heartworm antigen testing for 12 months.
The CR silicone implant containing 7.3 mg of ivermectin was 100% effective in preventing experimental infection with D immitislarvae and resulted in negative results for heartworm antigen in a field trial. This product has the potential to alleviate poor owner compliance with monthly prevention regimens.
评估含伊维菌素的带膜棒状（CR）硅胶植入物对犬长期预防感染犬恶丝虫的效果。
145只成年雌雄犬。
在3项临床前剂量选择研究中，给犬植入不同尺寸的植入物，并分别在16周、57周和56周监测伊维菌素浓度及血清伊维菌素浓度。在另外2项研究中评估植入物预防犬恶丝虫感染的能力；在植入物给药52周后，给犬接种50条感染性第三期幼虫，并在接种后145天进行尸检，计算成虫心丝虫的总数。然后进行了一项现场研究，客户拥有的犬接受植入物，并定期采集血浆样本，直至第52周进行伊维菌素分析和心丝虫抗原测定。
使用植入物可使伊维菌素浓度在12个月内维持≥0.2 ng/mL。在攻毒研究中，与未治疗的犬相比，没有一只治疗犬有成虫心丝虫，未治疗的犬在尸检时均有成虫心丝虫。在现场研究中，接受植入物治疗的犬12个月内心丝虫抗原检测结果均为阴性。
含7.3 mg伊维菌素的CR硅胶植入物在预防犬恶丝虫幼虫的实验性感染方面100%有效，且在现场试验中的心丝虫抗原检测结果为阴性。该产品有可能改善宠物主人对每月预防方案依从性差的问题。
