土霉素在子宫内膜炎奶牛血浆中的药动学试验

对8头健康和8头患子宫内膜炎奶牛经子宫内灌注土霉素注射液,研究了土霉素在奶牛血浆中的药动学特征.应用反向高效液相色谱法为检测手段对血浆中土霉素浓度进行测定,采用3p97药动学软件分析药-时数据.结果表明:土霉素在健康奶牛子宫内不易被吸收入血,而在患病奶牛血浆中的最高血药浓度较低.土霉素在患子宫内膜炎奶牛体内的药动学特征符合一级吸收一室开放模型,主要药动学参数:药时曲线下面积(AUC)为(18.53±10.92)mg.L-1.h-1,血药峰浓度(Cmax)为(1.66±0.84)μg/mL,达峰时间(tmax)为(0.35±0.06)h,吸收半衰期(t1/2ka)为(0.05±0.01)h,清除半衰期(t1/2ke)为(7.67±2.44)h.土霉素灌注给药在患子宫内膜炎的奶牛子宫内吸收快但不完全,消除较慢.     

乙酰甲喹在美洲鳗鲡体内的药物代谢动力学及残留研究

在水温(25±1)℃条件下,分别采用口灌和浸浴的给药方式,以120mg·kg~(-1)的单剂量混饲口灌及5mg·L~(-1)浸浴18h给予乙酰甲喹后,用高效液相色谱法测定血浆、肌肉、肝脏及肾脏中的药物浓度,研究不同给药方式下乙酰甲喹在美洲鳗鲡体内的药代动力学特征及残留情况。结果表明:乙酰甲喹原药在美洲鳗鲡体内吸收良好、代谢快、体内残留少。口灌给药后,血浆中药物浓度达峰时间T_(max)为0.75h,达峰质量浓度C_(max)为4 115μg·L~(-1),消除相半衰期T_(1/2)为7.40h,总体消除率CL/F为41.89L·kg~(-1)·h~(-1),72h后血浆、肌肉、肝脏及肾脏中几乎检测不到原药;浸浴给药血浆中药物浓度于0.25h达峰,达峰质量浓度C_(max)为435.6μg·L~(-1),消除相半衰期T_(1/2)为0.26h,总体消除率CL/F为1.241L·kg~(-1)·h~(-1),2.5h后各组织中几乎检测不到原药。2种方式给药乙酰甲喹在美洲鳗鲡血浆中分布均符合药动学一室开放模型。     

枳壳对丁螺环酮在健康大鼠体内药物动力学的影响

目的 研究枳壳对丁螺环酮在健康大鼠体内药物动力学的影响。方法 将SD大鼠随机分为丁螺环酮组,丁螺环酮加枳壳低剂量组（15 g/kg）,丁螺环酮加枳壳高剂量组（30 g/kg）,测定给药后5、10、20、30、45、60、90、120、240、360、480、600 min丁螺环酮的血药浓度,计算并比较其药动学参数。结果 与丁螺环酮组比较,丁螺环酮加枳壳低剂量组和高剂量组中丁螺环酮AUC_（0-t）分别增加2.49和4.18倍,C_max分别增加1.63和2.57倍,T_max从0.28 h分别延长至0.52和1.06 h,t_1/2从0.96 h分别延长至2.18和4.87 h,差异具有统计学意义（P<0.05）。结论 枳壳可增加同服药物丁螺环酮的AUC_（0-t）和C_max,提高丁螺环酮生物利用度,并有剂量依赖性趋势,枳壳与丁螺环酮发生显著的药动学相互作用。     

氟氯苯菊酯在犬体内的药动学初步研究

研究自制1%氟氯苯菊酯浇泼剂在健康家犬体内的药代动力学特征。选用6条健康犬,以2mg/kg单剂量沿背中线浇泼,采用反相高效液相色谱法(RP-HPLC)测定犬血浆中氟氯苯菊酯浓度,用3P97药动软件处理药时数据,计算药代动力学参数。氟氯苯菊酯的药时数据符合一级吸收二室开放模型,主要药动学参数为:T1/2α为(3.622±1.079)h,T1/2β为(22.654±0.417)h,T1/2Ka为(1.684±0.240)h,AUC为(47.385±1.709)μg.mL-1.h,Tpeak为(4.165±0.187)h,Cmax为(1.902±0.064)μg/mL,Lagtime为(0.489±0.002)h。健康家犬单次给予氟氯苯菊酯浇泼剂后,吸收、消除均缓慢,药物在动物体内作用时间较长。     

恩诺沙星在健康兔和人工感染巴氏杆菌兔体内的药代动力学研究

应用反相高效液相色谱法,对肌肉注射了恩诺沙星（Ｅｎｒｏｆｌｏｘａｃｉｎ） 的６ 只健康兔和６ 只人工感染巴氏杆菌兔体内的血药浓度进行了测试和药代动力学研究。应用非线性最小二乘法处理,实验数据参数用一室模型很好地描述。肌肉注射给药后,经过短暂的迟滞期（Ｌａｇｔｉｍｅ（ 健兔） ＝ ３－４６６４ ±１－１４９０ ｍｉｎ ,Ｌａｇｔｉｍｅ（ 病兔） ＝４－１９８４ ±０－９６１５ ｍｉｎ） ,血药浓度迅速上升,分布相很快完成（ｔ１／２ｋａ（ 健兔） ＝ ６－６４３２ ±３－６６７７ ｍｉｎ ,ｔ１／２ｋａ（病兔） ＝ ５－４８８４ ±１－９３３７ ｍｉｎ, 达峰时间ｔｐ（ 健兔） ＝ ３９－１９７２ ±１１－８９５１ ｍｉｎ ,ｔｐ（ 病兔） ＝ ２７－４６７０ ±６－０１２１ ｍｉｎ） 。之后,是一缓慢的消除相（ｔ１／２ｋｅｌ（ 健兔） ＝ ２４２－７０８０ ±５２－２７６５ ｍｉｎ,ｔ１／２ ｋｅｌ（ 病兔） ＝ １６０－８２３８ ±６６－１２７３ ｍｉｎ） ,表观分布容积Ｖｄ（ 健兔） ＝ ２－６４７０ ±１－５４１８ Ｌ／ｋｇ,Ｖｄ（ 病兔） ＝ １－５２２９ ±０－４２８０ Ｌ／ｋｇ 。机体清除率为ＣＬＢ（ 健兔） ＝ ７－１０００ ±２－６０００ ｍＬ／（ｋｇ·ｍｉ     

The kinetic disposition and dosage regimen for carbenicillin in buffalo calves

The distribution half-life, elimination half-life, apparent volume of distribution and total body clearance of carbenicillin in healthy buffalo calves following a single intravenous administration (50 mg/kg) were 0.057±0.005 h, 1.688±0.11 h, 0.185±0.021 L kg^-1 and 75.97±6.519 ml kg^-1 h^-1 respectively. A satisfactory dosage regimen for carbenicillin in buffalo calves was calculated to be 56 mg/kg followed by 52 mg/kg body weight repeated at 6 h intervals.     

The effect of water deprivation on the pharmacokinetics of antipyrine and sulphadimidine following intravenous administration in Nubian goats

The effect of water deprivation on the pharmacokinetic parameters of antipyrine and sulphadimidine in the Nubian goat was studied. Water deprivation, to a level of dehydration at which the animals lost an average of 7.5% body weight, resulted in a significant reduction in antipyrine clearance (p<0.05), and a consequently increased AUC value (p<0.05). No effect was observed on the distribution parameters of the drug. In dehydrated animals which had lost an average of 10% or 12.5% of their body weight owing to water deprivation, significant changes were found in the distribution and elimination pharmacokinetic parameters of antipyrine and sulphadimidine. The volume of distribution was significantly decreased, resulting in elevated plasma levels for the two drugs compared to normally watered animals. Significant decreases in clearance and subsequent prolongation of the elimination half-lives were observed during these periods of water deprivation. These changes in the disposition kinetics of the two drugs may be attributed to the loss of total body water and extracellular fluids and changes in the liver and kidney functions taking place during dehydration.     

Influence of subclinical nematodosis on the kinetic disposition of fenbendazole in buffaloes

The disposition kinetics of fenbendazole was studied in buffaloes subclinically infected with gastrointestinal nematodes. There was significantly reduced uptake of the drug in infected animals compared to uninfected controls. The pH of the duodenal liquor was highly alkaline compared to the acidic pH in uninfected animals. The egg count in the faeces never became zero though the numbers were reduced to a great extent compared to pre-treatment values. The influence of the host's physiology on the reduced bioavailability of fenbendazole is discussed.Abbreviations AUC area under the concentration-time curve - C _max peak concentration in plasma; - e.p.g. eggs per gram of faeces - ETH-OFZ ethyl oxfendazole - FBZ fenbendazole - FBZ-SO₂ fenbendazole sulphone - FEC faecal egg count - HPLC high-performance liquid chromatography - OFZ oxfendazole - T _1/2 half-life in plasma - T _max time to peak concentration in plasma     

耕牛锥－46药物代谢动力学研究

用反相高效液相色谱法测定了黄牛肌注锥－４６１ｍｇ／ｋｇ后１０、２０、３０、４５ｍｉｎ；１、１．５、２、３、４、６、８．１２、２４ｈ血浆中锥－４６浓度。经ＰＫＢＰ－ＮＩ程序与３Ｐ８７程序拟合，锥－４６在黄牛体内的代谢符合二室开放模型。其主要动力学参数为：Ｔ１／２α１００．９ｍｉｎ，Ｔ１／２β１２９１．４ｍｉｎ，Ｔ１／２Ｋａ７．８２５ｍｉｎ，ＡＵＣ１６４．８μｇ·ｍｉｎ／ｍｌ，Ｔｐ２７．４１ｍｉｎ，Ｃｍａｘ０．３３９μｇ／ｍｌ。提示黄牛对该药物吸收迅速，消除缓慢，在血液中滞留时间较长，故对伊氏锥虫有较好的杀灭效果。