伊维菌素在鲫体内的药代动力学

以0.4 mg/kg的给药剂量进行口灌和肌肉注射给药,研究伊维菌素(IVM)在鲫体内的药代动力学。两种给药方式下,鲫组织中的IVM药—时曲线大都呈现多峰现象。肌肉注射给药后,药动学统计矩参数为Cmax=0.445 mg/L、Tmax=48 h、t1/2z=524.2 h、MRT(0-∞)=788 h、AUC(0-∞)=289.2(mg/L).h;口灌给药后,药动学统计矩参数为Cmax=0.264 mg/L、Tmax=8 h、t1/2z=153.9h、MRT(0-∞)=269.78 h、AUC(0-∞)=83.77(mg/L).h。两种给药方式相比,口灌组鲫对药物的吸收和清除均较快,而肌肉注射组鲫各组织中的药物浓度高,AUC值也较大。两种给药方式下,IVM在鲫各组织中AUC(0-600)值呈现相同的排列顺序,由大到小分别为性腺、血液、肾脏、肝胰脏、肌肉。IVM在鲫性腺和肾脏中均具有一定的蓄积作用,其主要表现为药物浓度高,MRT值大,且清除率低于血药的清除率,其中卵巢的积蓄作用最为明显。25℃的水温条件下,肌肉注射给药后,鲫休药期应不低于25 d;口灌给药后,鲫的休药期应不低于15 d。休药期与水温条件和给药剂量有关,因此在养殖生产过程中的休药期要根据实际情况适当调整。     

诺氟沙星在金鳟体内的药物代谢动力学研究

实验水温为15±2℃,金鳟（Oncorhynchus mykiss）（平均体质量100±10g）单剂量肌肉注射30.0 mg/kg诺氟沙星后,应用高效液相色谱（HPCL）法于0.15,0.25,0.5,0.75,1,1.5,2,4,6,8,12,24,48,72 h测定了鱼血浆、肝脏和肾脏组织中药物的浓度,研究了诺氟沙星在金鳟组织中的分布及药物动力学规律。结果表明,诺氟沙星在金鳟体内吸收分布迅速,符合药物动力学一级吸收二室开放模型,但消除缓慢。诺氟沙星在金鳟血浆、肝脏和肾脏中的主要动力学参数如下：分布半衰期（T1/2α）分别为0.866、1.985、0.388h;消除半衰期（T1/2β）分别为31.369、36.402、30.975h;药时曲线下面积（AUC）分别为：308.005μg/mL.h、622.721μg/g.h、794.362μg/g.h。     

姜黄素固体分散体在猪体内的比较药动学研究

本研究首次建立了测定猪血浆中姜黄素的高效液相色谱串联质谱法（HPLC-MS/MS），比较了在内服给药途径下，姜黄素固体分散体和姜黄素预混剂在仔猪体内的药动学特征。选用16头7周龄左右健康二元杂交猪（约克夏×长白），公母各半，随机分为2组，每组8头，按100 mg·kg^-1（以姜黄素计）分别灌服姜黄素固体分散剂和姜黄素预混剂，不同时间点采集血浆样品，经提取、净化后采用HPLC-MS/MS测定血浆中姜黄素的药物浓度，使用WinNonlin 5.2.1软件非房室模型计算、分析姜黄素在猪体内的药动学参数。结果显示，仔猪灌服姜黄素固体分散体和姜黄素预混剂后的药时曲线下面积（AUC）分别为（104.53±38.67）和（37.82±11.48）h·ng·mL^-1；达峰时间（T_max）分别为（3.25±0.38）和（2.31±0.37）h；峰浓度（C_max）分别为（26.65±9.65）和（9.55±2.75）ng·mL^-1；消除半衰期（t_1/2β）分别为（3.55±2.17）和（6.93±0.86）h；平均驻留时间（MRT）分别为（5.23±0.53）和（4.26±0.47）h，统计分析表明，与预混剂相比，仔猪灌服姜黄素固体分散体后，主要药动学参数差异显著（P<0.01），T_max明显延迟，C_max显著提高，AUC明显增大，姜黄素固体分散体的相对生物利用度为280.39%。结果表明，姜黄素固体分散体可改善姜黄素在肠道的吸收，提高姜黄素的生物利用度，为今后姜黄素固体分散体的开发和临床应用提供科学依据。     

沙拉沙星/β-环糊精包合物微囊的特性分析

旨在制备并表征沙拉沙星/β-环糊精（SAR/β-CD）包合物微囊新制剂,测定增溶倍数和包封率,进行SAR/β-CD包合物微囊的体外溶出与体内药代动力学研究。采用搅拌法制备包合物微胶囊,用透射电镜、扫描电镜和粉末X光衍射技术进行物态表征。采用液相色谱法测定SAR/β-CD包合物微囊的增溶倍数和包封率,通过溶出试验研究SAR/β-CD包合物微囊在磷酸盐缓冲液（pH6.8）中的释放规律。最后,进行了环糊精包合物微囊在鸡体内的药代动力学评价。理化表征试验证明,药物进入β-环糊精空腔,成功获得了SAR/β-CD包合物微囊。3个试验批次的SAR/β-CD包合物微囊的平均增溶倍数和平均包封率分别为（25.3±1.15）倍和90.3%±0.15%。在磷酸盐缓冲液（pH6.8）中SAR/β-CD包合物微囊的溶出率为95.6%,而普通粉剂的溶出率仅为72.2%,包合反应后的制剂溶解度和溶出度均有显著提高。药代动力学试验中血药浓度检测的标准曲线为y=1.563 2x-0.189 6,R²=0.999 3,在0.25~10.00 μg·mL^-1内呈良好的线性关系。分析方法的精密度RSD值小于10%,分析方法的准确度大于90%,同时小于110%;回收率试验表明,低浓度（0.50 μg·mL^-1）回收率为90.55%±3.81%,中浓度（1.00 μg·mL^-1）回收率为93.85%±3.14%,高浓度（2.50 μg·mL^-1）回收率为98.19%±5.41%。冻融试验表明冻融稳定性（n=3）符合《中华人民共和国兽药典》（2015版）规定。鸡口服药代动力学试验表明,SAR/β-CD包合物微囊和沙拉沙星粉的AUC（mg·h^-1·L^-1）、T_max（h）、C_max（μg·mL^-1）分别为43.59±0.50、2.18±0.09、5.99±0.30和17.27±0.30、0.98±0.07、1.19±0.10。成功制备沙拉沙星/β-环糊精包合物微囊新剂型,明显提高了药物的溶出率和生物利用度,对喹诺酮类药物的推广应用具有重要意义。     

甲基睾丸酮在罗非鱼体内的药代动力学

以20 mg.kg-1和2 mg.kg-1剂量对经检测不含甲基睾丸酮残留的罗非鱼单次口灌给药,用高效液相色谱法测定血浆及组织中甲基睾丸酮(MET)的浓度。用乙酸乙酯提取样品,Florisil小柱净化。以3p97软件分析药时数据,MET在两个浓度组均符合一级吸收二室开放模型,吸收半衰期分别为0.29和0.28 h;分布半衰期分别为0.65和0.57 h,达峰时间分别为是0.78和0.60 h,消除半衰期分别为18.40和5.98 h。20 mg.kg-1组血液和肌肉中MET残留至144 h仍有检出,至216 h血液和肌肉样品MET均未检出;肝脏中的药物浓度高于血液和肌肉中的浓度,MET残留至24 h有检出,48 h的样品未检出。结果表明,口灌给药,MET在罗非鱼体内吸收、分布快,肝脏为主要吸收和代谢器官,与血液和肌肉相比消除速率要快,血液和肌肉中的MET消除速率相对较缓慢,因此开展MET监督检验除了常规的肌肉样品的检测外,还应增加血液样品的检测。     

HPLC-MS/MS法检测血根碱在鸡体内的药代动力学研究

为了建立给鸡灌胃血根碱后同时测定鸡血浆中血根碱及二氢血根碱浓度的HPLC-MS/MS检测方法,并评价血根碱在鸡体内的药代动力学特征,采用甲醇提取鸡血浆中的血根碱及代谢物二氢血根碱,以0.2%甲酸水(A)-乙腈(B)为流动相,选用Agilent Poroshell 120 EC C18(2.1 mm×150 mm,2.7μm)色谱柱进行色谱分离,采用电喷雾离子源(ESI)三重四极杆串联质谱进行分析,多重反应监测(MRM)方式进行检测。血根碱及代谢产物二氢血根碱均在0.1~50.0 ng/mL浓度范围内与色谱峰面积呈良好线性关系,提取回收率分别为88.95%~95.81%和82.00%~87.00%;日内及日间精密度(RSD)均小于15%;血根碱在鸡体内的药代动力学参数Cmax,Tmax,MRT,CL分别为0.90±1.053 ng/mL、0.38±0.30 h、5.11±0.74 h和44.09±3.05 h。血根碱在鸡体内血药达峰时间以及滞留在体内的平均时间较短,代谢物二氢血根碱的血药浓度是血根碱的血药浓度5.74倍,说明代谢物二氢血根碱的血药浓度远大于血根碱的血药浓度。该方法具有快速、灵敏度高、专属性强等特点,适用于同时测定鸡血浆中血根碱和二氢血根碱的血药浓度。     

新型兽用纳米乳载药系统在大鼠体内的药代动力学研究

为了解氟苯尼考纳米乳(FFNE)在大鼠体内药代动力学行为,本试验以氟苯尼考溶液(FFSol)为参比制剂,以30 mg/kg剂量给大鼠灌胃和肌内注射给药,分别于给药后0.5、1、2、4、8、12、24、36、48、72 h采血,利用高效液相色谱法测定血浆中氟苯尼考含量,利用DAS 2.0软件计算房室模型与非房室模型条件下药代动力学参数。结果显示,在两种给药方式下,FFNE与FFSol在大鼠体内均符合二室模型。灌胃给药后,FFNE与FFSol在房室模型条件下AUC_(0-∞)分别为1 085.047和2 176.490 mg/L·h,半衰期分别为10.566和13.687 h,FFNE的相对生物利用度为187.4%。肌内注射给药后,FFNE与FFSol在房室模型条件下AUC_(0-∞)分别为1 530.55和3 243.338 mg/L·h,半衰期分别为7.533和13.335 h,FFNE的相对生物利用度为211.9%。结果表明,FFNE通过灌胃和肌内注射给药在大鼠体内分布较广,灌胃相对肌内注射吸收差,消除快。将氟苯尼考制成纳米乳剂后促进了氟苯尼考的吸收,氟苯尼考的生物利用度显著提高。     

Pharmaco‐parasitological evaluation of the ricobendazole plus levamisole nematodicidal combination in cattle

The goals of the current study were to evaluate the potential pharmacokinetic (PK) interactions and the clinical efficacy occurring after the subcutaneous (s.c.) administration of ricobendazole (RBZ) and levamisole (LEV) given both separately and co‐administered to calves naturally infected with susceptible gastrointestinal nematodes. The clinical efficacy was shown in two seasons, winter and spring, with predominance of different nematode populations. Groups of 15 calves were treated with RBZ alone, LEV alone and RBZ + LEV combination, and an untreated group was kept as a Control. RBZ and LEV plasma concentrations were quantified by HPLC. The clinical efficacy was determined by the faecal egg count reduction test. RBZ and LEV have similar plasma persistence, being detected in plasma over 24 hr post‐treatment. No PK interactions were observed after the combined treatment, with similar PK parameters (p > .05) obtained for the single‐drug and the combination‐based strategy. In winter, the observed clinical efficacies were 96%, 99% and 100% for groups treated with RBZ, LEV and RBZ + LEV, respectively; however, in spring, the efficacies were 95%, 93% and 96% for the same groups. Remarkably, the combination was the only treatment that achieved 100% clinical efficacy against both Haemonchus spp and Ostertagia spp in winter; but the increased presence of Ostertagia spp. in spring (28% in untreated group) determined a tendency to reduced efficacies compared to winter time (only 10% of Ostertagia spp. in untreated group), even for the combined treatment. Overall, in a scenario where the nematode population is susceptible, the RBZ + LEV treatment may be a valid combination in cattle to delay the development of resistance, especially in winter when this combination achieved 100% of efficacy. Thus, selection of anthelmintic resistance will never occur. In fact, this is one of the greatest challenges for the whole cattle production system: to be one step ahead of anthelmintic resistance.     

Pharmacokinetics of enrofloxacin after oral,intramuscular and bath administration in crucian carp (Carassius auratus gibelio)

The pharmacokinetics of enrofloxacin (ENR) was studied in crucian carp (Carassius auratus gibelio) after single administration by intramuscular (IM) injection and oral gavage (PO) at a dose of 10 mg/kg body weight and by 5 mg/L bath for 5 hr at 25°C. The plasma concentrations of ENR and ciprofloxacin (CIP) were determined by HPLC. Pharmacokinetic parameters were calculated based on mean ENR or CIP concentrations using WinNonlin 6.1 software. After IM, PO and bath administration, the maximum plasma concentration (C_max) of 2.29, 3.24 and 0.36 μg/ml was obtained at 4.08, 0.68 and 0 hr, respectively; the elimination half‐life (T_1/2β) was 80.95, 62.17 and 61.15 hr, respectively; the area under the concentration–time curve (AUC) values were 223.46, 162.72 and 14.91 μg hr/ml, respectively. CIP, an active metabolite of enrofloxacin, was detected and measured after all methods of drug administration except bath. It is possible and practical to obtain therapeutic blood concentrations of enrofloxacin in the crucian carp using IM, PO and bath immersion administration.