伊维菌素微乳中伊维菌素的含量测定方法研究

为建立伊维菌素微乳中伊维菌素含量的高效液相色谱（HPLC）测定方法,选用Hypersil ODS2 （5 μm,4.6 mm×250 mm）色谱柱,流动相为甲醇∶乙腈∶水为35∶60∶5（V/V/V）,检测波长为244 nm,柱温为30 ℃,流速为1 mL/min进行测定。结果显示,伊维菌素在该色谱条件下,系统适应性良好,在80~320 μg/mL浓度范围内线性关系良好,回归方程为：Y=22 700X+2 510,R²=0.9998,总平均回收率为101.90%±2.94%,RSD为2.88%,对中试生产的3批伊维菌素微乳进行含量测定,RSD为1.86%。表明该含量测定方法准确可靠,重现性好,可用于伊维菌素微乳中伊维菌素含量的测定,并为该新型制剂的质量标准的制定和质量评价提供依据,也为后期的临床安全应用提供可靠的参考。     

伊维菌素干混悬剂对绵羊寄生虫的驱杀效果与安全性研究

选择1．5～2．0岁自然感染线虫和外寄生虫绵羊150只，分别按体重0．1、0．2、0．3mg／kg剂量口服伊维菌素干混悬剂，同时设口服伊维菌素片剂对照。结果显示，口服伊维菌素干混悬剂0．2、0．3mg／kg组绵羊的消化道线虫虫卵转阴率分别为93．3％和100％，减少率分别为99．2％和100％；原圆科线虫幼虫转阴率分别为90．0％和100％，减少率分别为94．5％和100％；平均驱虫率分别为98．4％和99．9％；绵羊颚虱、绵羊足颚虱全部被杀死，羊蜱蝇的转阴率分别为83．3％和87．5％。口服0．1mg／kg组绵羊的线虫虫卵（幼虫）转阴率、减少率、驱虫率均次于0．2、0．3mg／kg剂量组，对绵羊颚虱、羊蜱蝇的杀虫率较低。绵羊口服0．5mg／kg伊维菌素干混悬剂未出现明显异常反应。表明伊维菌素干混悬剂与片剂有同等的驱虫效果与安全性。     

伊维菌素防控山羊疥螨病的效果观察

为优化羊疥螨病的防控方法,从疥螨病患病率超过50％的132只山羊中,随机选取患病羊33只,依次平均分为3组,分别颈部皮下注射0.1、0.2和0.3 mg/kg的伊维菌素;未编入试验的99只病羊及健康羊,均同时颈部皮下注射0.2 mg/kg的伊维菌素;在注射伊维菌素的第5天,用0.2 mg/L伊维菌素·0.8 mg/L螺...     

伊维菌素浇泼剂和注射剂对牛皮蝇蛆病的治疗效果

为了解伊维菌素浇泼剂对牛皮蝇蛆病的治疗效果,探讨及筛选对牛皮蝇蛆病高效、低毒、使用方便的有效剂型,本临床试验共选用合格试验牛80头,随机分成5组:高剂量组(10头)、中剂量组(40头)、低剂量组(10头)、伊维菌素注射组(药物对照组10头)和不给药组(空白对照组10头),各组牛按如下方法给药:高、中、低剂量组分别按每100 kg体重15、10和5 mL背部浇泼给药,药物对照组按每100 kg体重2 mL颈部皮下注射伊维菌素。结果:伊维菌素浇泼剂高、中、低剂量组对牛皮蝇幼虫的杀虫效果三者之间差异不显著(P0.05),3个剂量组与药物对照组比较差异也不显著(P0.05),表明高、中、低剂量的伊维菌素浇泼剂和伊维菌素注射剂均对牛皮蝇均具有明显的驱虫效果。伊维菌素浇泼剂是一种新开发治疗牛皮蝇蛆病较为安全的局部外用药,使用简便、快捷,适合在临床上广泛推广应用。     

阿维菌素和伊维菌素对猪疥螨驱除效果研究

将30头感染疥螨的猪分成3组,用来测定阿维菌素类药物对疥螨的治疗效果,第1组注射1%阿维菌素注射液,第2组注射1%伊维菌素注射液,另设一不用药组作为对照。用药后第7天,重复用药1次,用药后第14、21、28天疥螨全部死亡,并且该类药对妊娠母猪、哺乳母猪、哺乳仔猪均无不良影响。     

多拉菌素和伊维菌素对牛、羊寄生虫的驱虫效果研究

目的:研究多拉菌素、伊维菌素对高寒阴湿地区放牧牛、羊寄生虫的驱治效果。对甘肃省张家川回族自治县林缘区7个试验点的42头牛、280只羊为研究对象。方法:按多拉菌素给牛0.3 mg/kg体重、羊0.2 mg/kg体重,伊维菌素给牛、羊均以0.02 m L/kg体重通过皮下或肌肉注射给药,以全身蠕虫剖检法及EPG来判定驱虫率。结果:发现相对于空白对照组来说,用药后多拉菌素组、伊维菌素组驱虫效果明显。结论:多拉菌素、伊维菌素对高寒阴湿地区牛、羊寄生虫均有较好的驱治效果,其中多拉菌素驱治效果最优。     

伊维菌素注射液对绵羊内外寄生虫驱除试验

用伊维菌素分低、中、高3个剂量组对60只绵羊进行了驱虫试验，结果表明，伊维菌素对绵羊鼻蝇的驱除率90％以上，虫卵减少率分别为82．4％、96．0％和96．4％。驱虫的最佳剂量为0．02ml／kg体重．     

伊维菌素长效注射液对小鼠的急性毒性试验

为考察伊维菌素长效注射液的急性毒性,用简化寇氏法对小鼠的LD50进行了测定。将伊维菌素长效注射液以1：0．7的组间剂量给试验小鼠一次皮下注射,连续观察7d。结果表明,伊维茵素长效注射液的LD50为257．04mg／kg,9500可信限范围为192．84mg／kg-342．61mg／kg,符合低毒标准,说明该药临床皮下注射使用安全。     

伊维菌素注射剂对牛皮蝇蛆病的防治效果试验

2014年10月5日至27日在克孜勒苏柯尔克孜自治州乌什县英阿瓦提乡和亚科瑞克乡共试验牛200头(黄牛)牛进行伊维菌素注射剂对牛皮蝇蛆病的防治效果试验.     

伊维菌素注射剂对牛皮蝇蛆病的防治效果实验

2004年10月15日至31日。在阿勒泰地区富蕴县和精河县分别每县1000头（黄牛）牛进行伊维菌素注射剂对牛皮蝇蛆病的防治效果实验。实验结果用伊维菌素（伊力佳）注射剂对牛皮蝇蛆病的防治效果达到100％，说明伊维菌素对牛皮蝇蛆很好的防治效果。     

Efficacy of dinotefuran, permethrin and pyriproxyfen combination spot-on against Aedes aegypti mosquitoes on dogs

A spot-on formulation combining permethrin, dinotefuran and pyriproxyfen (Vectra 3D? spot-on solution for dogs - one 10-25kg pipette contains 196mg dinotefuran, 1429mg permethrin and 17mg pyriproxyfen) was evaluated in adult Beagle dogs in a study designed to measure its efficacy to control Aedes aegypti (anti-feeding effect and mortality effect). The trial was performed according to Animal Welfare and Good Clinical Practice. Twelve dogs (five males and seven female, >3 years old, weighing 8.8-13.0kg) were randomly allocated to treatment groups on pre-treatment mosquito counts: six dogs served as untreated controls, and six dogs were treated with the test formulation. Treatment consisted of applying a combination formulation to deliver at least 46.6mgkg(-1) permethrin, 6.40mgkg(-1) dinotefuran and 0.57mgkg(-1) pyriproxyfen. The combination is designed to control fleas, ticks, sand flies and mosquitoes. Each dog was infested with approximately 100 adult unfed A. aegypti once before treatment (day 6) then at 1, 7, 14, 21 and 28 days post-treatment. Counts and engorgement determination of dead and live mosquitoes were performed after 1h exposure period. In the treated group (group A), the repellency effect of the product based on engorgement status (anti-feeding effect), was 91.5%, 94%, 94.7%, 94% and 87% at 1, 7, 14, 21 and 28 days post-treatment. Mortality effect or insecticidal efficacy calculated at the end of the 1-h exposure was almost identical when calculated 24h after the 1-h exposure and remained above 93% until the end of the in-life phase. No adverse events were observed following treatment, including observations conducted 2, 4 and 24h after the last dog was treated.     

Effects of artesunate treatment on Plasmodium gallinaceum transmission in the vectors Aedes aegypti and Culex quinquefasciatus

In the absence of vaccines, chemotherapy is an effective and economical way for controlling malaria. Development of anti-malarial drugs that target pathogenic blood stage parasites and gametocytes is preferable for the treatment as it can alleviate the host's morbidity and mortality and block transmission of the Plasmodium parasite. Recently, our laboratory has developed an in vivo transmission blocking assay that involves administration of 7 consecutive daily doses of a test compound into domestic chickens (Gallus gallus domesticus) infected with the avian malaria parasite Plasmodium gallinaceum with 10% parasitaemia and 1% gametocytaemia. To compromise the cost and time for artesunate (ATN) treatment, this study aimed to investigate effects of a 5-day consecutive administration of 10 milligrams per kilogram (mg/kg) ATN on P. gallinaceum infection in chickens and transmission to two natural vectors, Aedes aegypti and Culex quinquefasciatus. Our study showed that the treatment with 10 mg/kg ATN for 7 days, but not 5 days, completely eliminated blood stage infections, prevented recrudescence and blocked gametocyte production and transmission of P. gallinaceum to its vectors, thereby confirming the potent schizontocidal and gametocytocidal activities of ATN. This regimen should be further evaluated in field trials.     

Repellency and efficacy of a 65% permethrin spot-on formulation for dogs against Aedes aegypti (Diptera: Culicidae) mosquitoes

A topically applied 65% permethrin spot-on (Defend EXspot Treatment for Dogs, Schering-Plough Animal Health) used for flea and tick control on dogs was evaluated for repellency and efficacy against the yellow fever mosquito, Aedes aegypti, a vector of canine filariasis. Six dogs were randomly assigned to receive a single application of 65% permethrin on Day 0 (n=3) or to remain untreated as controls (n=3). Dogs were anesthetized and exposed to 100 unfed, female mosquitoes in screened cages for 2 hours on Days -6, -4, -1, 0, 1, 7, 14, 21, and 28. Mosquito landing rates, engorgement rates, and mortality were determined for each mosquito challenge. Cages were thoroughly cleaned after each mosquito challenge. Treatment of dogs with 65% permethrin reduced the mosquito landing rates by 96.3% 6 hours after treatment and by 82.5% on Day 1. Mosquito mortality, relative to the control group, was 28.2% 6 hours after treatment, ranged from 84.0% to 90.9% through Day 21, and declined to 50.3% 28 days after treatment. Successful feeding by mosquitoes was significantly (P=.05) reduced on Days 1 through 28. The 65% permethrin spot-on treatment killed and repelled significantly (P =.05) more mosquitoes on treated dogs versus untreated dogs for 28 days after treatment.     

Evaluation of mosquitoes, Aedes vexans, as biological vectors of porcine reproductive and respiratory syndrome virus

The objective of this study was to determine whether mosquitoes, Aedes vexans (Meigen), could serve as biological vectors of porcine reproductive and respiratory syndrome virus (PRRSV). Specifically, the study assessed the duration of viability and the site of PRRSV within mosquitoes, and evaluated whether PRRSV could be transmitted to a susceptible pig by mosquitoes following a 7- to 14-day incubation period after feeding on an infected pig. For the first experiment, a total of 100 mosquitoes were allowed to feed on a pig, experimentally infected with PRRSV (day 7 post-inoculation) and were then maintained alive under laboratory conditions. A set of 10 mosquitoes were collected at 0 hour (h), 6 h, 12 h, 24 h, 48 h, 72 h, 5 days (d), 7 d, 10 d, and 14 d post-feeding (pf). Samples of exterior surface washes, salivary glands, thorax carcasses, and gut homogenates were collected from each set of mosquitoes, and tested for PRRSV. Infectious PRRSV was detected by polymerase chain reaction and swine bioassay only from the gut homogenates of mosquitoes collected at 0 h and 6 h pf. For the second experiment, a total of 30 mosquitoes were allowed to feed on a pig, experimentally infected with PRRSV and the mosquitoes were then maintained under laboratory conditions. On each of day 7, 10, and 14 pf, a set of 10 mosquitoes were allowed to feed on a susceptible pig. Transmission of PRRSV to susceptible pigs did not occur, and PRRSV was not detected from the mosquitoes. These findings indicate that mosquitoes are not likely to serve as biological vectors of PRRSV.     

Mechanical transmission of porcine reproductive and respiratory syndrome virus by mosquitoes, Aedes vexans (Meigen)

The objective of this study was to determine whether porcine reproductive and respiratory syndrome virus (PRRSV) could be transmitted to naïve pigs by mosquitoes following feeding on infected pigs. During each of 4 replicates, mosquito-to-pig contact took place on days 5, 6, and 7 after PRRSV infection of the donor pig. A total of 300 mosquitoes [Aedes vexans (Meigen)] were allowed to feed on each viremic donor pig, housed in an isolation room. After 30 to 60 s, feeding was interrupted, and the mosquitoes were manually transferred in small plastic vials and allowed to feed to repletion on a naïve recipient pig housed in another isolation room. Prior to contact with the recipient pig, the mosquitoes were transferred to clean vials. Swabs were collected from the exterior surface of all vials, pooled, and tested for PRRSV. Separate personnel handled the donor pig, the recipient pig, and the vial-transfer procedure. Transmission of PRRSV from the donor to the recipient pig occurred in 2 out of 4 replicates. The PRRSV isolated from the infected recipient pigs was nucleic-acid-sequenced and found to be 100% homologous with the virus used to infect the donor pigs. Homogenates of mosquito tissues collected in all replicates were positive by either polymerase chain reaction or swine bioassay. All control pigs remained PRRSV negative, and PRRSV was not detected on the surface of the vials. This study indicates that mosquitoes (A. vexans) can serve as mechanical vectors of PRRSV.     

The incrimination of Aedes (stegomyia) aegypti as the vector of Dirofilaria repens in Nigeria

Six local species of culicides were identified as the common mosquitoes in Zaria, out of 15 species captured using various adult and larval collection methods. These common culicides are Culex pipiens fatigans, Anopheles gambiae grp., Mansonia africana, Culex pipiens pipiens, Aedes (stegomyia) aegypti and Aedes vittatus. They were each fed directly on a local dog naturally infected with Dirofilaria repens to evaluate their refractoriness/susceptibility to dirofilarial infection. In a number of donor-feeding trials, 39. 4% Culex pipiens fatigans; 58.9% An gambiae grp.; 60.5% Mansonia africana; 1.8% of Culex pipiens pipiens; 23.4% Ae aegypti and 3.3% of Ae vittatus successfully fed on the microfilaraemic host. Only Aedes aegypti was susceptible to the infection as all 40 (100%) Ae aegypti reaching 10-14 day post-blood meal had infective (L(3)) larvae of D. repens. The remaining five species were refractory. The microfilariae in the five non-susceptible mosquitoes were always found trapped in the blood meal in the insects midgut (stomach). These trapped microfilaria were dead by the 2nd day in the insect's midgut. However, in the susceptible Ae aegypti, the microfilariae were set free from the blood meal in the midgut and within 24h migrated to the malpighian tubules (MT) of the mosquitoes. All Ae aegypti dissected 5-7 day post-infective blood meal showed the typical quiescent sausage stage (L(2)) larvae in the malpighian tubules. At day-10 post-blood meal, relatively active infective (L(3)) larvae of D. repens were found in the MT; and by day 12-14, highly motile infective larvae had reached the insect's head and proboscis, with infective larvae occasionally oozing out during dissection through the tip of the proboscis. The rate of development of D. repens to infective larvae was faster in mosquitoes infected in July when the environmental temperature was 24.5 degrees C than those infected in November when the temperature was 22.5 degrees C. The latter were delayed for 4 days. The breeding sources of Ae aegypti, the local vector implicated were also identified. As no particular vector of this zoonotic filaria has been identified previously in Nigeria, these findings could make any control programme more focussed and easier.     

Pharmacokinetic studies of ivermectin: Effects of formulation

Studies are reported which describe the effects of formulation, animal species, and route of administration on the pharmacokinetics of ivermectin. Biological half-life t_1/2 increases in the order: swine (0.5 day) > dogs (1.8 day) > cattle sheep (2.8 day). Formulation modifications, based upon the solubility properties of the drug, have been directed towards the development of a nonaqueous injectable formulation for cattle and an aqueous vehicle for horses. Bioavailability following subcutaneous injection in cattle can be regulated by control of injection solvent composition: a vehicle composed of a mixed aqueous-organic solvent exhibits pharmacokinetic properties (i.e., C_p, t_1/2, AUC, and F) intermediate between those furnished by an aqueous formulation and via a purely nonaqueous solvent. The longer apparent biological half-life from this latter vehicle (t_1/2=8.3 days) confirms that a slow absorption process dominates the pharmacokinetics in the nonaqueous injectable product to produce an effective controlled-release formulation. These bioavailability results illustrate the increase in the concentration of an organic solvent and a concomitant decrease in surfactant concentration in a micellar aqueous system for prolonged drug delivery via injection.