复方磺胺嘧啶口灌给药在拟穴青蟹(Scylla paramamosain)体内药动学和组织分布与消除

研究了水温为(27±1)℃、盐度为10条件下,单剂量(100 mg/kg)口灌给药复方磺胺嘧啶(磺胺嘧啶SD:甲氧苄啶TMP=5:1)后,SD和TMP在拟穴青蟹(Scylla paramamosain)体内的药动学以及在肌肉、肝胰腺和鳃组织中的分布和消除规律.结果显示,拟穴青蟹口灌复方磺胺嘧啶后,血淋巴中SD和TMP药物浓度-时间关系曲线均符合一级吸收二室模型,SD和TMP的峰浓度(Cmax)分别为49.56 mg/L和2.79 mg/L,药时曲线下面积(AUC)分别为1417.6 mg/L.h和82.7 mg/L·h;肝胰腺是SD和TMP峰浓度最高的组织,其Cmax分别为59.36 mg/kg和74.82 mg/kg.由此可见,大量TMP蓄积在肝胰腺中,进入血液循环的TMP很少.在鳃组织中,SD和TMP的Cmax分别为51.89 mg/kg和42.58 mg/kg,消除半衰期分别为23.28 h和25.29 h;鳃组织中药物浓度比较高,且消除速度较快,推测其在药物代谢中承担着消除功能.在肌肉中,SD和TMP的Cmax分别为44.95 mg/kg和10.09 mg/kg,消除半衰期分别为25.09 h和35.08 h.以0.1 mg/kg和0.05 mg/kg分别为SD和TMP的最高残留限量(MRL),95％置信区间,推算SD和TMP在拟穴青蟹肌肉中的理论休药期分别为290.6 h和302.8 h,在肝胰腺中分别为340.4 h和377.0 h.     

Oxytetracycline (OTC) accumulation and elimination in hemolymph, muscle and hepatopancreas of white shrimp Litopenaeus vannamei following an OTC-feed therapeutic treatment

The white shrimp, Litopenaeus vannamei, has become a very important species for the development of shrimp aquaculture in Northwest Mexico. However, viral and bacterial diseases are considered a major threat to the development of this industry. In the present study a trial was conducted to evaluate the tissue distribution, maximum concentration, and elimination of the widely used antibiotic oxytetracycline (OTC) in L. vannamei using indoor tanks under laboratory-controlled conditions. OTC was given to shrimp simulating a therapeutic treatment through medicated feed for 14 days followed by a period of feeding without antibiotic for another 14 days to evaluate the elimination pattern. Samples of hemolymph, muscle, and hepatopancreas were taken from medicated animals every two days for 28 days. All tissues were removed and frozen immediately in liquid nitrogen. OTC levels were analyzed by High Performance Liquid Chromatography (HPLC). Results showed an important OTC increase during consumption of medicated feed in all examined tissues. OTC maximum concentrations were 33.54 ± 11.19, 194.37 ± 16.11, and 18.79 ± 5.87 µg g^− 1 for muscle, hepatopancreas and hemolymph, respectively. Although the highest OTC level was found in the hepatopancreas, it required only two days after the start of dosing to reach this value, whereas the maximum OTC for muscle and hemolymph was detected after eight days of dosing. Ten days after the cessation of medicated feeding, the drug content in the shrimp tail muscle was under the detectable limit for the method (0.01 µg g^− 1 of OTC).     

氟苯尼考静注及肌注在绵羊体内的药代动力学研究

健康绵羊8只,随机分为A、B两组,A组静注单剂量20mg·kg-1氟苯尼考试验品,B组肌注单剂量30mg·kg-1氟苯尼考试验品。两周后,A组肌注单剂量20mg·kg-1氟苯尼考试验品,B组肌注单剂量20mg·kg-1氟苯尼考对照品。用高压液相色谱法测定血浆中的药物浓度。采用3p97药代动力学程序软件处理药 时数据。静注药 时数据符合三室开放模型,主要药代动力学参数:Vd(ss)1 87±0 26L·kg-1,T1/2α1 5±0 06h,T1/2β19 47±7 64h,CL(s)0 25±0 05L·kg-1·h-1,AUC77 35±10 24μg·h·mL-1;氟苯尼考试验品肌注药 时数据符合一室开放模型,主要药代动力学参数:20mg·kg-1剂量组C(max)4 20±0 28μg·mL-1,T1/2ka0 26±0 02h,T1/2ke10 07±1 08h,AUC67 47±11 02μg·h·mL-1,F(绝对)87 22%,F(相对)97 66%;30mg·kg-1剂量组C(max)7 10±1 84μg·mL-1,T1/2ka0 26±0 10h,T1/2ke9 57±3 28h,AUC101 58±10 25μg·h·mL-1。实验结果表明,氟苯尼考试验品肌注后曲线下面积AUC与剂量呈比例关系,在绵羊体内吸收好,分布快,消除缓慢,与先灵葆雅公司对照品相似。     

磺胺二甲嘧啶及其N4—乙酰化物在健康和发病兔的动力学

本文研究磺胺二甲嘧啶(SDM)及其N_4-乙酰化代谢物(N_4SDM)在健康和急性多杀性巴氏杆菌病兔的药物动力学。快速静注200mg/kg后,SDM的V_(ss)、Cl_B和t(1/2)β分别为0.7±0.3L/kg、0.57±0.24L/(kg·h)和1.6±1.3h。N_4-乙酰化代谢是本药的主要消除方式,所给剂量62.1％以该方式消除。另有12.7±1.1和2.8±1.8％药物以原形分别从肾脏和胃肠道排泄。N_4SDM的形成和消除半衰期分别为0.6±0.4和2.2±1.1h。它主要从肾脏排泄消除。急性多杀性巴氏杆菌病对SDM和N_4SDM的药动学没有显著影响。     

喹乙醇在肉鸡体内的组织动力学与残留的研究

研究了喹乙醇在肉鸡体内的组织动力学过程及在组织中的残留。并对血药和组织药物浓度进行动态相关分析。结果表明,药物按一级速率过程从组织中消除,药物在心、肝、肾、肌肉各组织中的半衰期分别为1.96、2.89、3.11、1.77小时。药物在各组织中的残留时间以肾脏最长、肌肉最短。     

Pharmacokinetics of IV Ketorolac in Horses Undergoing Orchiectomy

Ketorolac (KET) is a nonsteroidal anti-inflammatory drug for human use, with a potent analgesic activity, that is used in the relief of moderate-to-severe postoperative pain. The pharmacokinetics of KET tromethamine was evaluated after single IV injection at 0.5 mg/kg body weight, after intubation and 10 minutes before surgery, to six Arabian colts undergoing orchiectomy. Intraoperative cardiorespiratory variables were monitored. Blood samples were collected for 36 hours, and serum samples were analyzed by high performance liquid chromotography with ultraviolet-visible detection. During surgery, all monitored physiological parameters were stable. Intermittent positive pressure ventilation, and normocapnia were maintained throughout the procedure in all animals. No adverse effects were observed. The kinetics of KET was described by a two-compartment models, and also a noncompartmental analysis was performed. The distribution and elimination half-lives were t_1/2λ1$t_{1/2{\lambda }_1}$ 0.06 ± 0.02 and t_1/2λ2$t_{1/2{\lambda }_2}$ 0.59 ± 0.21 hours, respectively. Body clearance and mean residence time were 339.99 ± 120.19 mL/h/kg and 0.49 ± 0.22 hours, respectively. The volume of distribution at steady state and volume of distribution based on the terminal phase were 218.83 ± 134.26 mL/kg and 522.5 ± 529.3 mL/kg, respectively. The serum protein binding was 75.8 ± 2.9%. The results indicate that KET at 0.5 mg/kg IV was very rapidly eliminated and thus was likely not effective in the postoperative period. However, further studies including a control group and at higher doses are suggested to investigate the KET kinetics and the analgesic efficacy in horse and define the most appropriate dosage scheme.     

Pharmacokinetics of the Novel Cyclooxygenase 2 Inhibitor Cimicoxib in Donkeys

Cimicoxib is a novel cyclooxygenase 2 inhibitor drug approved for use in dogs. Assessing pharmacokinetic profiles in target species is pivotal for extra-label applications. The purpose of the present study was to evaluate the pharmacokinetic profiles of cimicoxib after intragastric administration in six healthy jennies. Plasma concentrations of cimicoxib were determined by high performance liquid chromatography with fluorescence detector. A pilot study was carried out with two animal groups (n = 3) in fasted or fed conditions receiving 2 mg/kg of cimicoxib. Because of the relatively low C_max (0.03 μg/mL) from the pilot study, the dose was increased (5 mg/kg) for the subsequent full-scale crossover study. Single administration of 5 mg/kg did not show any adverse effects. However, the C_max (0.02 μg/mL) and area under the curve (0.14 hour × μg/mL) values obtained after 5 mg/kg administration were not dose dependent compared with those in the 2 mg/kg pilot study. The results from this study could provide basic but essential information for the use of cimicoxib. Further pharmacodynamic studies are required to assess clinical efficacy in donkeys at these low plasma concentrations.     

Breed-related plasma disposition of ivermectin following subcutaneous administration in Kilis and Damascus goats

Many factors related with drug and animals affect the plasma disposition of endectocides including ivermectin (IVM). The aim of the present study was to investigate the breed differences in pharmacokinetics of IVM in goats following subcutaneous administration. Two different goat breeds (Kilis and Damascus goats) were allocated into two treatment groups with respect to breed. The injectable formulation of IVM was administered subcutaneously at a dose rate of 0.2 mg/kg bodyweight. Blood samples were collected before treatment and at various times between 1 h and 40 days after treatment and the plasma samples were analysed by high performance liquid chromatography (HPLC) using fluorescence detection. The results indicated that the plasma disposition of IVM was substantially affected by breed differences following subcutaneous administration in goats. The last detectable plasma concentration (t_last) of IVM was significantly later in Kilis goats (38.33 days) compared with Damascus goats (22.50 days). Although, there were no significant differences on C_max (10.83 ng/ml vs. 10.15 ng/ml) and t_max (2.75 days vs. 2.33 days) values; the area under the concentration–time curve-AUC (110.26 ng.d/ml vs. 73.38 ng.d/ml) the terminal half-life-t_1/2λz (5.65 days vs. 3.81 days) and the mean plasma residence time-MRT (9.31 days vs. 6.35 days) were significantly different in Kilis goats compared with Damascus goats, respectively. The breed-related difference observed on the plasma disposition of IVM between Kilis and Damascus goats could be attributable to different excretion pattern or specific anatomical and/or physiological characteristics such as body fat composition of each breed.     

Pharmacokinetics and tissue tolerance of azithromycin after intramuscular administration to rabbits

The pharmacokinetics of azithromycin after intravenous and intramuscular injection at a single dose rate of 10mg/kg bodyweight were investigated in rabbits by using a modified agar diffusion bioassay for determining plasma concentrations. The plasma creatine kinase activity was determined after i.m. administration for the evaluation of the tissue tolerance. The elimination half-lives of azithromycin after intravenous and intramuscular administration were 24.1 and 25.1h, respectively. After intramuscular administration mean peak plasma concentration was 0.26+/-0.01 mg/L and bioavailability was 97.7%. Plasma CK activity rose sharply within 8h after i.m. injection of azithromycin; activity returned to pre-treatment level by 48-72 h post-treatment. The transient rise in serum CK activity indicates some degree of muscle tissue damage at the injection site.