Pharmacokinetics of Enrofloxacin and Its Metabolite Ciprofloxacin after Intramuscular Administration of Enrofloxacin in Goats

The pharmacokinetics of enrofloxacin and its active metabolite ciprofloxacin were investigated in goats after a single intramuscular administration of enrofloxacin at 2.5 mg/kg body weight. The plasma concentrations of enrofloxacin and ciprofloxacin were determined simultaneously by a HPLC method. The peak concentrations (C _max) of enrofloxacin (1.13 g/ml) and ciprofloxacin (0.24 g/ml) were observed at 0.8 and 1.2 h, respectively. The elimination half-life (t _1/2), volume of distribution (V _d(area)), total body clearance (Cl_B) and mean residence time (MRT) of enrofloxacin were 0.74 h, 1.42 L/kg, 1329 ml/h per kg and 1.54 h, respectively. The t _1/2, area under the plasma concentration–time curve (AUC) and the MRT of ciprofloxacin were 1.38 h, 0.74 g h/ml and 2.73 h, respectively. The metabolic conversion of enrofloxacin to ciprofloxacin was appreciable (36%) and the sum of the plasma concentrations of enrofloxacin and ciprofloxacin was maintained at or above 0.1 g/ml for up to 4 h. Enrofloxacin appears to be useful for the treatment of goat diseases associated with pathogens sensitive to this drug.     

Some Pharmacokinetic Data for Danofloxacin in Healthy Goats

The pharmacokinetics of danofloxacin was determined in five clinically normal adult female goats after intravenous (IV) or intramuscular (IM) doses of 1.25 mg/kg body weight. Blood and urine samples were collected from each animal at precise time intervals. Serum and urine concentrations were determined using microbiological assay methods and the data were subjected to kinetic analysis. After intravenous injection, the serum concentration–time curves of danofloxacin were characteristic of a two-compartment open model. The drug was rapidly distributed and eliminated with half-lives of 17.71±1.38 min and 81.18±3.70 min, respectively. The drug persisted in the central, highly perfused organs with a K ₁₂/K ₂₁ ratio of 0.67±0.25. The mean volume of distribution at a steady state (V _dss) was 1.42±0.15 L/kg. After intramuscular administration, the serum concentration peaked after 0.58±0.04 h at approximately 0.33±0.01 g/ml. While danofloxacin could be detected in serum for 4 and 6 h, it was recovered in urine for up to 24 and 72 h after IV and IM administration, respectively. The systemic bioavailability after IM injection was 65.70%±10.28% and the serum protein-bound fraction was 13.55±1.78%.     

“一针肥”注射液中硒元素在山羊体内的药代动力学研究

为研究＂一针肥＂注射液中硒元素在山羊体内的血硒水平及药动学变化规律,采用单剂量肌肉注射＂一针肥＂注射液0.2mL/kg（相当于硒用量6μg/kg）,用原子荧光法测定血硒浓度,通过3p97药物动力学程序软件分析药时数据。结果显示,肌注＂一针肥＂注射液后,血硒的药时数据符合二室开放模型,主要的药代动力学参数分别为：t1/2Ka（0.148 4±0.051 0）h,t1/2α（6.832 4±0.397 7）h,t1/2β（362.324 3±17.789 5）h,Kel（0.004 3±0.000 3）h,AUC（22 414.233 5±2 512.959 8）（μg/L）.h。结果表明,肌注＂一针肥＂注射液后硒在山羊体内吸收迅速,消除缓慢。     

恩诺沙星长效注射液肌注后在猪体内的药动学研究

研究了恩诺沙星长效注射液给猪肌注后的药物动力学特征。将12只白猪随机分成两组,每组6只,分别肌注恩诺沙星注射液(5mg/kg)和长效恩诺沙星注射液(18.75mg/kg),并于给药后0.1, 0.25, 0.5, 1, 2, 4, 8, 12, 24, 36, 48, 60h, 从前腔静脉采取5ml血,用HPLC分析各血浆样品中的药物浓度,用MCPKP软件计算药动学参数。结果表明:长效恩诺沙星注射液肌注后,经5.64h达到4.86μg/ml的最高浓度,吸收半衰期和消除半衰期分别为2.42h和19.47h,有效浓度维持时间为128.73h, AUC为166.96mg/L.h。吸收半衰期显著延长(p<0.05),达峰时间极显著推迟(p<0.01),消除半衰期也显著长于恩诺沙星注射液。     

恩诺沙星及其活性代谢物在鸡体内的药物动力学

为全面了解恩诺沙星在鸡体内的动力学过程与药效的关系进行了本研究。用反向高效液相色谱法测定鸡血浆中的药物质量浓度,所得恩诺沙星ｃｉ－ｔｉ数据用ＭＣＰＫＰ计算机程序处理,代谢物环丙沙星的ｃｉ－ｔｉ数据用代谢物动力学方法处理。静注恩诺沙星后的ｃｉ－ｔｉ数据符合二室开放模型,主要动力学参数：ｔ１／２α（０．２５±０．０４）ｈ,ｔ１／２β（５．２６±０．８１）ｈ,Ｖｄ（４．５３±１．０７）Ｌ／ｋｇ,ＣＬＢ（０．６１±０．１１）Ｌ／（ｋｇ·ｈ）,ＡＵＣ（１７．３９±３．９２）ｍｇ／（Ｌ·ｈ）。内服恩诺沙星的ｃｉ－ｔｉ数据,符合有吸收因素二室模型,主要动力学参数ｔ１／２ｋａ（０．４４±０．１１）ｈ,ｔ１／２α（１．１５±０．３８）ｈ,ｔ１／２β（９．１４±１．４５）ｈ,ＡＵＣ（１２．４８±２．３６）ｍｇ／（Ｌ·ｈ）,ｔｍａｘ（１．７７±０．２１）ｈ,Ｃｍａｘ（１．４４±０．３１）ｍｇ／Ｌ,Ｆ７２．１８％。试验结果表明,鸡静注与内服恩诺沙星后,代谢物环丙沙星的生成及消除缓慢、分布广泛,是影响恩诺沙星疗效的重要因素。     

恩诺沙星微囊在猪体内的药动学及生物利用度研究

为了比较恩诺沙星微囊和原粉在猪体内的药动学特征及生物利用度,试验采用高效液相色谱法(HPLC),将10头健康猪分2组采用正交试验,经灌胃给药后采血、甲醇提取和HPLC分析,所得药时数据用MCPKP计算机程序处理。恩诺沙星微囊和原粉经口服给药后在猪体内的药时数据均符合一级吸收一室模型,主要药动学参数分别为:t1/2Ka1.73 h±0.93 h和0.36 h±0.31 h(P0.01);Tmax5.69 h±1.68 h和2.04 h±1.06 h(P0.01);t1/2Ke16.53 h±5.23 h和10.17 h±1.87 h(P0.01);Cmax1.71μg/mL±0.47μg/mL和2.51μg/mL±0.45μg/mL(P0.01);AUC为每小时51.98μg/mL±16.08μg/mL和40.58μg/mL±6.40μg/mL;微囊的相对生物利用度为128%。说明恩诺沙星微囊口服给药吸收较慢但完全,达峰时间较长,消除缓慢。     

恩诺沙星在猪体内的生物利用度及药物动力学研究

选用２１头健康杂种猪，随机分为３组，对静注、肌注及内服恩诺沙星（２．５ｍｇ／ｋｇ）的生物利用度和药物动力学进行了研究。用乙腈提取血浆中的药物，反相高效液相色谱法测定血浆中恩诺沙星及其主要代谢产物环丙沙星的浓度。所得血药浓药－时间数据用ＭＣＰＫＰ计算机程序处理。静注给药的药时数据适合二室开放模型，主要药物动力学参数：ｔ１／２ａ０．４８±０．２４ｈ；ｔ１／２ａ３．４５±０．８５ｈ；ｔ１／２Ｋ１０２．０     

恩诺沙星注射液中非法添加磺胺嘧啶HPLC-PDA检查法的建立

对恩诺沙星注射液中非法添加磺胺嘧啶的检测方法进行了研究.通过比较受试样品中未知峰与对照品色谱图保留时间的一致性和光谱指数图的匹配,建立了HPLC-PDA测定法,并进行相应的方法学研究.结果显示,磺胺嘧啶回收率为99.5％,RSD=0.4％;线性方程为y=873577x＋98154,R2 =1;检测限为5μg/mL,表明该检测方法准确可靠,可用于恩诺沙星注射液中非法添加磺胺嘧啶的检测.     

Some Pharmacokinetic Parameters of Pefloxacin in Lactating Goats

The aim of this study was to elucidate some of the pharmacokinetic parameters of pefloxacin in lactating goats (n = 5) following intravenous (i.v.) or intramuscular (i.m.) injections of 10 mg/kg bw. Serially obtained serum, milk and urine samples were collected at precise time intervals, and the drug concentrations were assayed using a microbiological assay. A two-compartment open model best described the decrease of pefloxacin concentration in the serum after intravenous administration. The maximum serum concentration (C _p ⁰ ) was 8.4±0.48 g/ml; elimination half-life (t _1/2) was 1.6±0.3 h; total body clearance (Cl_tot) was 3.6±0.3 L/kg/h; steady-state volume of distribution (V _dss) was 5.14±0.21 L/kg; and the area under the curve (AUC) was 2.78±0.22 g.ml/h. Pefloxacin was absorbed rapidly after i.m. injection with an absorption half-life (t _1/2ab) of 0.32±0.02 h. The peak serum concentration (C _max) of 0.86±0.08 g/ml was attained at 0.75 h (T _max). The absolute bioavailability after i.m. administration was 70.63±1.13% and the serum protein-bound fraction ranged from 7.2% to 14.3%, with an average value of 9.8±1.6%. Penetration of pefloxacin from the blood into the milk was rapid and extensive, and the pefloxacin concentration in milk exceeded that in serum from 1 h after administration. The drug was detected in milk and urine for 10 and 72 h, respectively; no samples were taken after 72 h.     

乳酸恩诺沙星可溶性粉在鸡体内的药动学研究

24只苏禽黄羽肉鸡随机分成2组,分别按10 mg/kg体重剂量静注和内服乳酸恩诺沙星。测定乳酸恩诺沙星在鸡体内的药动学参数和生物利用度。恩诺沙星血药浓度数据用3p87计算机软件处理。静注乳酸恩诺沙星后的血药浓度-时间数据符合二室开放模型,主要动力学参数:t1/2α(0.45±0.16)h,t1/2β(7.02±1.42)h,CL(s)(0.38±0.10)L/kg/h,AUC(23.69±5.56)(mg/L)×h。内服乳酸恩诺沙星的血药浓度时间数据,符合有吸收因素二室模型,主要动力学参数:t1/2ka(0.60±0.01)h,t1/2ke(8.25±1.73)h,tpeak(2.44±0.17)h,Cmax(1.44±0.30)mg/L,AUC(20.74±3.80)(mg/L)×h,F 87.54%。结果表明,乳酸恩诺沙星可溶性粉在鸡体内具有吸收快、分布广、消除较慢以及内服生物利用度高的药动学特征。     

Pharmacokinetics of Enrofloxacin and Its Metabolite Ciprofloxacin in Male and Female Turkeys following Intravenous and Oral Administration

The pharmacokinetics of enrofloxacin (EFL) was investigated in turkeys (6 male and 6 female; 7-month-old at the start of the experiment), after intravenous and oral administration at a dose of 10 mg/kg body weight. The serum concentrations of EFL and its active metabolite ciprofloxacin (CFL) were determined by high-performance liquid chromatography. The serum concentrations vs time were analysed by a compartmental analysis. The mean values of EFL pharmacokinetic parameters showed differences only between values of V_d,ss (3.46±0.19 for the females and 4.53±0.11 L/kg for the males, p>0.05). The metabolite CFL was eliminated more slowly than its parent compound. There were no statistically significant differences between the values of the CFL pharmacokinetic parameters calculated for both sexes, excluding the higher values (p>0.05) of C_max in the females. The ratio AUC_CFL/AUC_EFL×100 was 4.4% in the male and 6.84% in the female birds. After oral administration of EFL the values of F(%) were 77.83 in the female and 79.61 in the male turkeys. Higher CFL serum concentrations were measured in females (p>0.05). The pharmacokinetics of enrofloxacin and its metabolite ciprofloxacin in turkeys can be characterized as similar to that in chickens and very similar between both sexes.     

Pharmacokinetics and Dosage Regimen of Enrofloxacin in Buffalo Bulls after Intramuscular Administration

The disposition kinetics and dosage regimen of enrofloxacin were investigated in breeding buffalo bulls following a single intramuscular administration of 5 mg/kg. The absorption half-life, half-life of the terminal phase, apparent volume of distribution and total body clearance were 0.262±0.099 h, 1.97±0.23 h, 0.61±0.13 L/kg and 210.2±18.6 ml/(kg.h), respectively. Therapeutic plasma levels (1 g/ml) were maintained for up to 6 h. A satisfactory intramuscular dosage regimen for enrofloxacin in buffalo bulls would be 8.5 mg/kg followed by 8.0 mg/kg at 8 h intervals.     

恩诺沙星及其活性代谢物在传染性鼻炎鸡体的药动学

为建立鸡传染性鼻炎的药动学模型,研究了恩诺沙星及其活性代谢物在传染性鼻炎鸡体内的药动学特征.用反向高效液相色谱法测定血浆中的药物浓度,所得恩诺沙星的ci-ti数据用MCPKP程序处理,代谢物环丙沙星的ci-ti数据用代谢物动力学方法处理.结果表明,鸡静注恩诺沙星后的ci-ti数据符合二室开放模型,其主要动力学参数如下:t1/2α(0.25±0.04) h、t1/2β(5.46±0.71) h、Vd(4.21±1.09) L/kg、CLB(0.54±0.11) L/(kg.h)、AUC(19.68±3.50) mg/(L.h).鸡内服恩诺沙星的ci-ti数据,符合有吸收因素二室模型,其主要动力学参数如下:t1/2ka(0.44±0.11) h、t1/2α(1.17±0.40) h、t1/2β(9.24±2.07) h、AUC(12.23±3.68) mg/(L.h)、tmax(1.50±0.29) h、Cmax(1.34±0.44) mg/L、F 62.26%.恩诺沙星在感染鸡体内的动力学特征是吸收迅速、分布广泛、消除缓慢;感染鸡静注与内服恩诺沙星后,代谢物环丙沙星的动力学特征是生成及消除缓慢、分布广泛.鸡传染性鼻炎可使恩诺沙星内服的生物利用度下降,但对恩诺沙星的分布、消除及代谢物的动力学过程无显著影响.     

恩诺沙星及其代谢产物在奶山羊的药动学及乳中药物浓度

本试验研究单剂量静脉注射、肌肉注射和乳房灌注恩诺沙星（2.5mg/kg)在健康奶山羊的药动学及乳中药物浓度。采用HPLC法测定血浆和乳中恩诺沙星及其代谢产物环丙沙星的浓度，用统计矩原理处理血浆中药物浓度－时间数据，计算非房室模型的药动学参数。静脉注射、肌肉注射和乳房灌注恩诺沙星的t1/2β分别为1.32、1．55、0．99h;AUC为1．06、3．04、2．66mghL^-1；恩诺沙星的代谢分数为35．01％、44．06％、45．73％；环丙沙星的t1/2β为1．81、2．94、2．32h。乳中的药物浓度高于同期血中药物浓度，且乳中环丙沙星浓度高于恩诺沙星浓度并维持更长的时间。     

Pharmacokinetics of Pefloxacin in Goats after Intravenous or Oral Administration

The plasma concentrations and pharmacokinetics of the fluoroquinolone antimicrobial agent pefloxacin, following the administration of a single intravenous (10 mg/kg) or oral (20 mg/kg) dose, were investigated in healthy female goats. The antimicrobial activity in plasma was measured at predetermined times after drug administration by an agar well diffusion microbiological assay, using Escherichia coli (ATCC 25922) as the test organism. Concentrations of the drug 0.25 g/ml were maintained in plasma for up to 6 and 10 h after intravenous (IV) or oral administration of pefloxacin, respectively. The concentration–time data for pefloxacin in plasma after IV or oral administration conformed to two- and one-compartment open models, respectively. Plasma pefloxacin concentrations decreased rapidly during the initial phase after IV injection, with a distribution half-life (t _1/2 ) of 0.10±0.01 h. The terminal phase had a half-life (t _1/2 ) of 1.12±0.21 h. The volume of distribution at steady state (V _dss), mean residence time (MRT) and total systemic clearance (Cl_B) of pefloxacin were 1.08±0.09 L/kg, 1.39±0.23 h and 821±88 (ml/h)/kg, respectively. Following oral administration of pefloxacin, the maximum concentration in the plasma (C _max) was 2.22±0.48 g/ml and the interval from administration until maximum concentration (t _max) was 2.3±0.7 h. The absorption half-life (t _{1/2 ka}), mean absorption time (MAT) and elimination half-life of pefloxacin were 0.82±0.40, 4.2±1.0 and 2.91±0.50 h, respectively. The oral bioavailability of pefloxacin was 42%±5.8%. On the basis of the pharmacokinetic data, a dosage regimen of 20 mg/kg, IV at 8 h intervals or orally twice daily, is suggested for treating infections caused by drug-sensitive pathogens in goats.     

Pharmacokinetics of Amoxicillin Trihydrate in Desert Sheep and Nubian Goats

The pharmacokinetics of amoxicillin were studied in five Desert sheep and five Nubian goats after intravenous (i.v.) or intramuscular (i.m.) administration of a single dose of 10 mg/kg body weight. Following i.v. injection, the plasma concentration-versus-time data were best described by a two-compartment open model. The kinetic variables were similar in both species except for the volume of the central compartment (V_c), which was larger in sheep (p<0.05). Following i.m. injection, except for the longer half-life time of absorption in goats (p<0.05), there were no significant differences in other pharmacokinetic parameters between sheep and goats. The route of amoxicillin administration had no significant effect on the terminal elimination half-life in either species. The bioavailability of the drug (F) after i.m. administration was high (>0.90) in both species. These results indicate that the pharmacokinetics of amoxicillin did not differ between sheep and goats; furthermore, because of the high availability and short half-life of absorption, the i.m. route gives similar results to the i.v. route. Therefore, identical intramuscular and intravenous dose regimens should be applicable to both species.     

Some Pharmacokinetic Parameters of Eprinomectin in Goats following Pour-on Administration

Some pharmacokinetic parameters of eprinomectin were determined in goats following topical application at a dose rate of 0.5 mg/kg. The plasma concentration versus time data for the drug were analysed using a one-compartment model. The maximum plasma concentration of 5.60±1.01 ng/ml occurred 2.55 days after administration. The area under the concentration–time curve (AUC) was 72.31±11.15 ng day/ml and the mean residence time (MRT) was 9.42±0.43 days. Thus, the systemic availability of eprinomectin to goats was significantly lower than that for cows. The low concentration of eprinomectin in the plasma of goats suggests that the pour-on dose of 0.5 mg/kg would be less effective in this species than in cows. Further relevant information about the optimal dosage and residues in the milk of dairy goats is needed before eprinomectin should be used in this species.     

The Plasma Kinetics and Tissue Distribution of Enrofloxacin and its Metabolite Ciprofloxacin in the Muscovy Duck

Intorre, L., Mengozzi, G., Bertini, S., Bagliacca, M., Luchetti, E. and Soldani, G., 1997. The plasma kinetics and tissue distribution of enrofloxacin and its metabolite ciprofloxacin in the Muscovy duck. Veterinary Research Communications, 21 (2), 127-136The disposition and tissue distribution of enrofloxacin and of its main metabolite ciprofloxacin were investigated in ducks after oral or intramuscular administration of a single dose of 10 mg/kg enrofloxacin. Plasma and tissue concentrations were determined by a HPLC method. The peak concentrations of enrofloxacin after intramuscular administration (1.67 µg/ml at 0.9 h) were higher than after an oral dose (0.99 µg/ml at 1.38 h). The relative bioavailability of enrofloxacin after administration directly into the crop was 68%, while the metabolic conversion of enrofloxacin to ciprofloxacin was quite low (<10%) with both routes of administration. High tissue concentrations and high tissue:plasma concentration ratios were demonstrated for enrofloxacin and ciprofloxacin 24 h after treatment. It was concluded that a dose of 10 mg/kg per day provides serum and tissue concentrations sufficiently high to be effective in the control of many infectious diseases of ducks.     

Endometrial Tissue Concentrations of Enrofloxacin after Intrauterine Administration to Mares

Endometritis in mares is a common cause of infertility. Conventional treatments of the disease have mostly been unsuccessful, so new therapeutic alternatives need to be investigated. This study evaluated the uterine disposition and plasma pharmacokinetic behaviour of a commercial formulation of enrofloxacin (EFX) given by the intrauterine (i.u.) route (2.5 mg/kg) in healthy mares. In order to evaluate the uterine inflammatory response, an initial histopathological study assessing polymorphonuclear cell infiltration was carried out in 20 mares over a 14-day period after treatment. In a second study, 6 healthy adult mares were used for the pharmacokinetic study. Samples of uterine tissue and plasma were collected from 0 to 24 h after the i.u. treatment with 5% EFX solution. Samples were analysed by conventional microbiological assay using an EFX-sensitive strain of Escherichia coli (ATCC 25922). There was a moderate but statistically nonsignificant inflammatory response following i.u. administration of either the formulation or the vehicle alone. Pharmacokinetic analysis of the uterine concentrations of EFX showed a slow and sustained depletion, with EFX remaining at concentrations above the MIC for 24 h after treatment. The area under the concentration–time curve obtained for the uterus suggested that EFX and its metabolites are specifically retained in the uterus, which is the target tissue for bacterial colonization. Neither study provided any evidence of EFX toxicity. In conclusion, these results are encouraging and suggest that EFX may be a useful local treatment in mares with bacterial endometritis.     

HPLC-PDA联合UPLC-Triple TOF MS法确证恩诺沙星注射液中的非法添加物

为确证1批恩诺沙星注射液中的非法添加物,通过HPLC-PDA法初筛,利用高分辨质谱对未知物进行筛查,并用HPLC-PDA和UPLC-Triple TOF MS两种方法进行验证,结果显示,该批样品中的非法添加物为加替沙星.本研究为兽药中非法添加物筛查及定性确证提供了一个有效的思路与方法.