恩诺沙星混悬液的研制及其在鸡组织中的残留研究

以恩诺沙星为主药,采用正交试验筛选配方,研制恩诺沙星混悬液,并对该制剂的药剂学特征及其在鸡组织中的残留进行研究。药剂学研究表明,混悬液的性状、pH及药物含量均符合混悬剂质量要求,且稳定性良好、易于再分散。健康鸡在饮水中添加75 mg/L(以恩诺沙星计)混悬液,自由饮水,连续用药5 d后休药;休药第5天,肌肉、肝脏及"皮肤+脂肪"组织中药物总残留量(恩诺沙星+环丙沙星)分别为11.12±10.53、79.29±28.86、50.08μg/kg±22.09μg/kg,而肾脏组织未检出;休药第8天,肌肉、肾脏、肝脏组织中均未检出恩诺沙星及环丙沙星,"皮肤+脂肪"的总残留量为13.84μg/kg±10.82μg/kg。采用WT1.4软件处理数据,计算出该混悬液在鸡体内的休药期为6 d。     

恩诺沙星混悬液在猪体内的药动学及生物利用度

本文比较了恩诺沙星混悬液和恩诺沙星溶液在猪体内的药动学特征和生物利用度。选用 7头健康猪按拉丁方设计进行静注、肌注恩诺沙星溶液和肌注恩诺沙星混悬液在猪体内的药物动力学研究。 3种给药方法的剂量均为 10mg/kg。猪静注给药的药时数据符合二室开放模型 ,主要药动学参数为 :t1/ 2α0 6 4± 0 15h ,t1/ 2 β9 0 6± 2 47h ,Vd(area) 4 40± 0 88L/kg ,ClB0 35± 0 0 6L·kg-1·h-1,AUC2 9 85± 4 11L·kg-1·h。猪肌注恩诺沙星溶液和恩诺沙星混悬液的药时数据符合一级吸收一室模型 ,其主要药动学参数分别为t1/ 2ka0 2 4± 0 10h和 1 2 5± 1 0 9h(P <0 0 5 ) ;t1/ 2ke8 90± 2 0 2h和 18 95± 4 5 5h(P <0 0 1) ;Tmax1 2 5± 0 41h和 5 14± 2 95h(P <0 0 1) ;Cmax1 5 4± 0 2 5 μg/ml和 0 87± 0 2 1μg/ml;AUC2 1 49± 4 94mg·L-1·h和 2 8 97± 10 80mg·L-1·h ;F72 0 %±17 4%和 97 7%± 35 0 %。比较肌注恩诺沙星混悬液和恩诺沙星溶液的主要药动学参数 ,二者有显著差异 ,前者的t1/ 2ka、Tmax、t1/ 2ke和Cmax分别为后者的 5 2、4 1、2 1和 0 6倍。这些差异说明恩诺沙星混悬液肌注后吸收缓慢 ,消除半衰期延长 ,临床应用 48h给药 1次仍能维持对常见病原菌的有效血药     

恩诺沙星微囊制剂在猪体内残留消除规律研究

采用高效液相色谱法研究恩诺沙星微囊制剂在猪体内各组织中的残留消除规律。恩诺沙星微囊制剂混饲,连续给药7 d,宰杀猪,取组织。组织样品经磷酸盐缓冲液提取,C18固相萃取柱净化,过膜,用流动相:0.05 mol/L磷酸溶液/三乙胺-乙腈(82+18)溶解,微孔过滤,进行HPLC分析。结果表明,当样品浓度为0.02～1μg/g时,线性关系良好。该法最低检测限为20μg/kg,回收率在72%～90%之间,变异系数小于10%。残留在肌肉、脂肪中的恩诺沙星和环丙沙星消除较快,第5天总残留量已下降至检测限以下;肝和肾脏中的残留药物消除较缓慢,第7天肾中药物总残留量为91.48μg/kg。综合各组织中总残留量和MRL规定,建议恩诺沙星微囊制剂休药期为7 d。     

恩诺沙星口服混悬液的研制及其对仔猪黄白痢疗的效观察

以恩诺沙星为原料,纯化水为溶媒,利用胶体磨采用分散法研制出恩诺沙星口服混悬液,并对制剂进行了稳定性研究.结果显示,所有参试样品的外观性状、沉降体积比、再分散性、相对含量等指标均无明显变化,表明该制剂稳定性良好.结果表明,试验组与对照组对仔猪黄白痢的治愈率分别为72.0%和66.0%,有效率分别为92.0%和72.0%,试验组对仔猪黄白痢的有效率与对照组比较差异极显著(P＜0.01),表明恩诺沙星口服混悬液对仔猪黄白痢的临床疗效显著优于恩诺沙星溶液.     

恩诺沙星混悬液对人工诱发鸡大肠杆菌病的疗效观察

为验证恩诺沙星口服混悬液对鸡大肠杆菌病的临床疗效,选用人工诱发大肠杆菌病的鸡为试验对象,以恩诺沙星溶液的疗效为对照。结果显示,恩诺沙星混悬液的高、中、低剂量与恩诺沙星溶液组的有效率分别为96.7%、90.0%、80.0%和73.3%,均极显著高于感染组自愈率(P<0.01);高剂量组有效率极显著高于恩诺沙星溶液组(P<0.01),中剂量组显著高于同等剂量的恩诺沙星溶液组(P<0.05),而低剂量组的有效率稍高于恩诺沙星溶液组,差异不显著(P>0.05)。     

恩诺沙星在猪组织中残留消除规律研究

在常规饲养条件下,对健康猪按2.5 mg/kg体重的剂量肌肉注射2.5%恩诺沙星注射液,每日2次,连续注射3 d.停药后第2、4、6、8、10、12、14天分别屠宰4头猪.分别采取每头猪的肌肉(注射部位)、脂肪(腹脂)、肝和肾脏等4种组织,用高效液相色谱法进行残留量测定.结果表明:残留在肌肉、脂肪组织中的药物消除较快,第8天总残留量(恩诺沙星 环丙沙星)已下降至检测限(20μg/kg)以下;肝和肾脏组织中的药物消除缓慢,第14天测得猪肾中药物总残留量为40μg/kg.     

鸡猪排泄物中恩诺沙星和环丙沙星含量HPLC检测方法的建立

建立了测定鸡、猪排泄物中恩诺沙星及环丙沙星含量的高效液相-荧光检测方法.将猪粪和鸡粪尿混合物样品分别用甲醇氨水溶液和醋酸甲醇溶液浸提,猪尿用固相萃取小柱富集净化,流动相为乙腈-三乙胺磷酸溶液（0.02 mol/L）,荧光激发波长280 nm,发射波长450 nm.检测结果表明,排泄物样品中恩诺沙星和环丙沙星含量的检测定量限,鸡粪尿混合物为0.010 μg/g,猪尿0.005 μg/mL,猪粪为0.020 μg/g.外标法标准曲线的线性范围鸡粪尿混合物中恩诺沙星为0.010～100.000 μg/g、环丙沙星为0.010～50.000 μg/g,猪尿和猪粪中恩诺沙星和环丙沙星的线性范围分别为0.005～0.500 μg/mL和0.020～1.000 μg/g.恩诺沙星和环丙沙星的回收率分别大于75%和88%.HPLC方法的样品前处理和检测方法简便、快捷,准确性较微生物检测法高.     

高效液相色谱法检测复方制剂中恩诺沙星和痢菌净的含量

用HPLC方法测定了复方制剂中恩诺沙星和痢菌净的含量。色谱柱SUPELCOSILTMLC 18(2 5cm× 4 .6mm ,5 μm) ,柱温 30℃ ,流动相为甲酸 三乙胺 乙腈 水 (6∶3∶16.3∶84 .7) ,流速 1.2ml/min ,进样量 10 μl。恩诺沙星、痢菌净的检测波长分别为 2 80nm和 374nm ,线性范围分别为 0 .5～ 5 0 μg/ml(r =0 .9992 )和 1～ 10 0 μg/ml(r =0 .9997)。平均回收率分别为99.5 1% (RSD =1.83% )和 99.37% (RSD =1.69% )。本文还讨论了流动相的成份和比例对恩诺沙星色谱峰的拖尾影响 ,并对两药物的分离度进行了讨论     

恩诺沙星在猪血清和组织液中对大肠杆菌的半体内药动-药效同步模型的研究

为合理应用恩诺沙星治疗猪大肠杆菌感染.本研究采用了体内药动和体外药效联合的方法,研究了恩诺沙星在血清和组织笼液中抗大肠杆菌的活性.体外测定结果显示,恩诺沙星在血清和组织笼液中对猪大肠杆菌的MIC均为0.4 μg·mL-1.如果在血清和组织液中添加更多的细菌,则需要高于MIC药物浓度才能持续抑制细菌的生长.猪按5 mg·kg-1的剂量肌内注射恩诺沙星后,血清中半效浓度(EC50)为77.67±31.12,即恩诺沙星血清药物浓度为1.29μg·mL-1时可产生50%最大效应;组织液中恩诺沙星的半效浓度(EC50)为15.78±4.99,即组织液药物浓度为0.26μg·mL-1时可产生50%最大效应.结果提示,临床应用恩诺沙星治疗大肠杆菌感染时,应适当提高给药的剂量,不应仅以高于MIC作为制定给药间隔的标准.     

恩诺沙星对17℃负压环境下猪精子保存效果的影响

为研究猪精子在17℃负压环境下保存时不同浓度恩诺沙星对精子质量的影响,并探讨恩诺沙星的最适添加浓度,试验在Modena基础稀释液中添加不同浓度恩诺沙星并在17℃负压环境下保存猪精液,利用迈朗全自动精子质量检测仪等检查猪精子活率、路径速度、直线速度和畸形率。结果表明:恩诺沙星浓度为50μg/L时,精子活率、路径速度、直线速度和畸形率都显著高于其他浓度(P0. 05)。说明50μg/L的恩诺沙星有利于17℃负压环境下猪精液的保存。     

猪排泄物中恩诺沙星和环丙沙星含量的HPLC检测方法

为了对猪排泄物中恩诺沙星(enrofloxacin,ENR)和环丙沙星(ciprofloxacin,CIP)进行定量检测,试验建立了测定猪粪尿中ENR和CIP含量的高效液相－荧光检测方法。将猪粪经乙腈－氨水超声提取后,加入三氯乙酸酸化,然后分别将经磷酸酸化后的猪尿和提取后的猪粪溶液经固相萃取小柱富集净化,取净化液进行HPLC分析。HPLC流动相为乙腈(A):柠檬酸/乙酸铵缓冲液(B),梯度洗脱:0~25 min,A 10%~40%;25~30 min,A 40%至10%,荧光检测器的激发波长278 nm,发射波长465 nm。结果表明,ENR和CIP 在尿中的最低检测限(LOD)<0.01 mg/L,在粪中的LOD<0.021 mg/kg,在尿中的最低检测限(LOQ)<0.03 mg/L,在粪中LOQ<0.056 mg/kg,猪尿中的ENR和CIP在0.01~1.0 mg/mL范围内线性关系良好,R²分别为0.9994和0.9992;猪粪中的ENR和CIP在0.02~2.0 mg/mL范围内线性关系良好,R²分别为0.9986和0.9981。ENR在猪粪和猪尿中的回收率分别为79.4%和88.5%,CIP在猪粪和猪尿中的回收率分别为75.8%和89.9%。该方法样品处理简单,检测结果准确可靠,且灵敏度较高,是值得推广的检测方法。     

Method for Determination of Enrofloxacin and Ciprofloxacin in Pig Excreta by HPLC

A HPLC-FLD method was developed for determination of enrofloxacin (ENR) and ciprofloxacin (CIP) levels in feces and urine of pig.The pig feces was ultrasonic extracted by acetonitrile-ammonia, then added trichloroacetic acid to make the extraction acidification.The pig urine was acidulated by phosphoric acid and the extraction of feces solution were enriched and purified by solid phase extraction small column, took purification liquid for HPLC analysis.Conditions of HPLC mobile phase was acetonitrile (A):citric acid/ammonium acetate buffer (B), the procedure of gradient elution was 0 to 25 min, A:10% to 40%;25 to 30 min, A:40% to 10%.The detector of fluorescence excitation wavelength was 278 nm, emission wavelength was 465 nm, chromatographic data were measured and recorded.The results showed that the LOD of ENR and CIP were lower than 0.01 mg/L in urine and 0.021 mg/kg in feces, the LOQ of ENR and CIP were lower than 0.03 mg/L in urine and 0.056 mg/kg in feces.ENR and CIP in the concentration of 0.01 to 1.0 mg/mL levels range had good linear relationship, R² were 0.9994 and 0.9992 in pig urine, respectively;ENR and CIP in the concentration of 0.02 to 2.0 mg/mL levels range had good linear relationship, R² were 0.9986 and 0.9981 in pig feces, respectively.The recovery ratio of ENR were 79.4% and 88.5%, and the recovery ratio of CIP were 75.8% and 89.9% in pig feces and urine.After get on validation, the method was easy in sample processing and testing, the results were accurate, reliable and high sensitivity, which was a worth promoting detection method.     

Depletion study and estimation of the withdrawal period for enrofloxacin in pacu (Piaractus mesopotamicus)

Defining the pharmacokinetic parameters and depletion intervals for antimicrobials used in fish will help in the development of important guidelines for future regulations by Brazilian agencies on the use of these substances in fish farming. This paper presents a depletion study for enrofloxacin (ENR) and its main metabolite, ciprofloxacin (CIP), in pacu (Piaractus mesopotamicus) fillets. The depletion study was carried out under monitored environmental conditions, with the temperature controlled at 27 °C to mimic the fish farming conditions in Brazil. ENR was administered orally via medicated feed for 10 consecutive days at daily dosages of 10 mg/kg body weight (b.w.). The fish were slaughtered at 6, 12, and 24 h and 2, 3, 5, 8, 12, 17, and 24 days after the medication period. Considering a maximum residue limit of 100 μg/kg for the sum of the ENR and CIP residues in the fillet, the results obtained in the depletion study allowed the estimation of a half‐life for ENR of 2.75 days and a withdrawal period of 23 days. The results obtained in this study are important for the farming of pacu in tropical regions.     

Pharmacokinetics of enrofloxacin following intravenous administration to greater rheas: a preliminary study

The pharmacokinetic behaviour of enrofloxacin (ENR) and its active metabolite ciprofloxacin (CIP) were determined in six greater rheas following a single intravenous (i.v.) dose of 15 mg/kg bw. Plasma concentrations of ENR and CIP were simultaneously determined by a HPLC/u.v. method. Following i.v. administration, the plasma drug concentrations were best fitted by an open two-compartment model with a rapid distribution phase. The high volume of distribution (V(ss)=5.01 L/Kg) suggests good tissue penetration. ENR presents a high clearance (3.95 L/kg h) explaining the low AUC values (3.57 mg h/L) and a short permanence (t(1/2beta)=2.66 h and MRT=1.23 h). Ciprofloxacin comprised 14% of the total fluoroquinolone (ENR+CIP).     

盐酸沃尼妙林预混剂在猪组织中残留消除规律研究

建立了猪肝脏、肾脏、肌肉和脂肪中盐酸沃尼妙林的高效液相色谱检测方法并研究盐酸沃尼妙林预混剂在猪体内各组织中的残留消除规律。对24头健康猪以200mg/kg的剂量混饲给药21d。在停药后0、6、12、18、24、36h分别宰杀4头猪,采集各组织进行药物残留测定。方法的检测限为0.025～0.062 5μg/g,定量限为0.05～0.1μg/g,肝脏的平均回收率为75.5%～76.4%,变异系数为2.3%～3.8%;肾脏的平均回收率为75.8%～78.5%,变异系数为4.1%～6.0%;肌肉的平均回收率为79.3%～80.0%,变异系数为3.0%～4.7%;脂肪的平均回收率为76.7%～77.3%,变异系数为3.3%～5.4%。结果表明,盐酸沃尼妙林在肝脏中残留量最高,肾脏其次;肌肉和脂肪中的残留量显著低于肝脏和肾脏,停药24h时,残留量低于定量限;停药36h时残留量均低至检测限以下。盐酸沃尼妙林预混剂在猪组织中消除迅速,建议休药期为2d。     

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.     

Comparison of fluoroquinolone pharmacokinetic parameters after treatment with marbofloxacin, enrofloxacin, and difloxacin in dogs

Plasma, urine, and skin drug concentrations were determined for dogs (n=12) given five daily oral doses of marbofloxacin (MAR) (2.75 mg/kg), enrofloxacin (ENR) (5.0 mg/kg) or difloxacin (DIF) (5.0 mg/kg). Concentrations of the active metabolite of ENR, ciprofloxacin (CIP), were also determined. The three-period, three-treatment crossover experimental design included a 21-day washout period between treatments. Area under the plasma drug concentration vs. time curve (AUC0-last, microg/mLxh of MAR was greater than for ENR, CIP, ENR/CIP combined, and DIF. Maximum concentration (Cmax) of MAR was greater than ENR, CIP, and DIF. Time of maximum plasma concentration (Tmax) was similar for MAR and DIF; Tmax occurred earlier for ENR and later for CIP. Plasma half-life (t1/2) of MAR was longer than for ENR, CIP, and DIF. Urine concentrations of DIF were less than MAR or ENR/CIP combined, but urine concentrations of MAR and ENR/CIP combined did not differ. DIF skin concentrations were less than the concentrations of MAR or ENR/CIP combined 2 h after dosing, but skin concentrations of MAR and ENR/CIP combined did not differ.     

Tylosin depletion from edible pig tissues

The depletion of tylosin from edible pig tissues was studied following 5 days of intramuscular (i.m.) administration of 10 mg/kg of tylosin to 16 crossbreed pigs. Animals were slaughtered at intervals after treatment and samples of muscle, kidney, liver, skin+fat, and injection site were collected and analysed by high-performance liquid chromatography (HPLC). Seven days after the completion of treatment, the concentration of tylosin in kidney, skin+fat, and at the injection site was higher than the European Union maximal residue limit (MRL) of 100 microg/kg. Tylosin residues in all tissues were below the quantification limit (50 microg/kg) at 10 and 14 days post-treatment.     

Comparative pharmacokinetics of enrofloxacin in healthy and Aeromonas hydrophila‐infected crucian carp (Carassius auratus gibelio)

The comparative pharmacokinetics of enrofloxacin (ENR) and its metabolite ciprofloxacin (CIP) were investigated in healthy and Aeromonas hydrophila‐infected crucian carp after a single oral (p.o.) administration at a dose of 10 mg/kg at 25 °C. The plasma concentrations of ENR and of CIP were determined by HPLC. Pharmacokinetic parameters were calculated based on mean ENR concentrations by noncompartmental modeling. In healthy fish, the elimination half‐life (T_1/2λz), maximum plasma concentration (C_max), time to peak (T_max), and area under the concentration–time curve (AUC) values were 64.66 h, 3.55 μg/mL, 0.5 h, and 163.04 μg·h/mL, respectively. In infected carp, by contrast, the corresponding values were 73.70 h, 2.66 μg/mL, 0.75 h, and 137.43 μg·h/mL, and the absorption and elimination of ENR were slower following oral administration. Very low levels of CIP were detected, which indicates a low extent of deethylation of ENR in crucian carp.