HPLC法测定磷酸替米考星可溶性粉中有关物质的研究

建立HPLC法测定磷酸替米考星可溶性粉中的有关物质。采用C18柱(250 mm×4.6 mm, 5μm)色谱柱,以水-磷酸二丁胺溶液=975∶25为流动相A,以乙腈为流动相B,进行梯度洗脱,流速为1.1 mL/min,检测波长280 nm,进样量10μL。在拟定的色谱条件下,磷酸替米考星可溶性粉中反式异构体是两个不完全分开的峰,顺式异构体与顺-8差向异构体主色谱峰与相关的杂质完全分离,制剂中的辅料对主成分及有关物质测定无干扰;4家企业11批样品单个杂质与各杂质的和分别小于3.0%和9.0%。说明该方法可用于磷酸替米考星可溶性粉有关物质的质量控制。     

HPLC法测定复方替米考星颗粒中有效成份含量

采用HPLC法同时测定了复方替米考星颗粒中替米考星、磺胺二甲氧嘧啶及甲氧苄啶的含量。色谱柱为Eclipse XCB-C18(250 mm×4.6 mm,粒径5μm),流动相为磷酸二丁胺缓冲液-乙腈-四氢呋喃-水(25∶115∶55∶805),检测波长280 nm,流速1.0 mL/min。出峰顺序为甲氧苄啶、磺胺二甲氧嘧啶、替米考星反式结构、替米考星顺式结构,理论塔板数分别为7963、15714、3282、8701。两峰之间的分离度分别为24.29、3.92、2.91;拖尾因子分别为0.92、0.90、0.97、0.94。替米考星、磺胺二甲氧嘧啶、甲氧苄啶的浓度线性范围分别是6.25～125μg/mL(R2=0.996),3.125～62.5μg/mL(R2=0.996),0.625～12.5μg/mL(R2=0.999);平均回收率分别为99.17%、99.06%和99.39%;RSD分别为0.8%、0.9%和0.9%。该法快速、灵敏、准确,适用于同时测定复方替米考星颗粒中三种成份的含量。     

高效液相色谱法测定饲料中替米考星含量

为建立饲料中替米考星含量的高效液相色谱检测分析方法，实验样品经水-乙腈-磷酸二丁胺溶液-四氢呋喃（805:115:25:55，V:V:V:V）提取后，振荡10 min，超声10 min，4000 r/min离心5 min，取上清液过0.45 μm有机微孔滤膜后供高效液相色谱仪分析测定。结果表明：替米考星在10 ~ 500 μg/mL质量浓度范围内线性关系良好，相关系数大于0.999，方法检出限为5 mg/kg，定量限为10 mg/kg，平均回收率为92.0% ~ 101.2%，相对标准偏差为1.02% ~ 5.17%。该方法操作简单，重复性好，准确率高，且上机8 min即可完成替米考星的检测，适用于饲料中替米考星含量的测定。 [关键词] 饲料|替米考星|高效液相色谱法     

高效液相色谱法测定饲料中替米考星含量

本实验建立了测定饲料中替米考星含量的高效液相色谱(HPLC)检测方法。将2g饲料样品,经乙腈、乙腈-磷酸二氢钾缓冲液提取后过C18萃取柱净化、蒸干、流动相溶解后进行HPLC检测分析。流动相检测波长为290nm,流速1.0mL/min。结果表明:在1～500μg/mL的浓度范围内替米考星的峰面积(顺式和反式异构体的峰面积之和)与浓度呈良好的线性关系(r=1),平均回收率为81.4%以上,RSD小于6.1%,检测限为1μg/g。     

不同工艺制备的替米考星颗粒体外释放度研究

通过考察3种替米考星颗粒制剂在酸性溶液和缓冲液中的释放情况，为新制剂的进一步研发和临床应用提供理论依据。采用高效液相色谱法对3种不同制剂中替米考星的含量及其体外溶出度进行测定。色谱柱选择Hypersil ODS-2 C18(4.6 mm×250 mm, 5μm),以水∶乙腈∶四氢呋喃∶磷酸二丁胺(790∶130∶55∶25)为流动相，流速1.0 mL/min,检测波长290 nm,柱温30℃。分别以盐酸溶液和磷酸盐缓冲液为溶出介质，测定3种新研制的替米考星不同制剂体外溶出曲线，溶出方法选用浆法，转速为75 r/min,温度为37℃±0.5℃。在所建立的方法学基础上，替米考星在10μg/mL～1000μg/mL范围内与峰面积呈良好的线性关系，在90 min时3种新研制的替米考星不同制剂在酸性溶液中的溶出度分别为100%、5.73%和8.29%,供试品1与供试品2、供试品3及对照品之间差异显著(P<0.05),供试品2、供试品3与对照品之间无明显差异；120 min时3种新研制的替米考星不同制剂在磷酸盐缓冲液中的累积溶出度分别为100%、97.53%和93.60%,3种供试品与对照品...     

高效液相色谱法测定替米考星含量

建立了替米考星含量测定的HPLC方法。采用C18色谱柱(5μm,4.6 mm×250mm),乙腈+四氢呋喃+磷酸二丁胺为流动相,流速1.0 mL/m in,检测波长280 mn,以HPLC外标法测定替米考星含量。结果表明,实验测得的峰面积与对应的浓度呈良好的线性关系,其线性范围为0.25~0.75 mg/mL(r=0.999 9),平均回收率为99.81%。本法简便、准确、快速,是测定替米考星含量的良好方法。     

超高效液相色谱法测定原料药中泰地罗新的含量

本实验建立超高效液相色谱法（UPLC）测定泰地罗新原料药中泰地罗新及其异构体的含量。采用ACQUITY UPLC BEH C18色谱柱(2.1 mm×100 mm，1.7 μm)，流动相为0.05 mol/L磷酸氢二钾缓冲液（磷酸调pH值至8.2）-乙腈（45：55），检测波长289 nm，流速 0.5 mL/min，柱温:40 ℃，进样量:1 μL。通过光谱图、保留时间和峰面积参数对泰地罗新进行定性、定量检测。泰地罗新在0.2-2.4mg/mL 的范围内呈良好的线性关系（R2=0.9992）；方法检测限为0.2 mg/mL，定量限为0.6 mg/mL；精密度、重复性、稳定性完全满足检测需求。说明该方法快速、准确、分离度好，可快速检测泰地罗新原料药中泰地罗新及其异构体的含量。     

牛奶中替米考星间接竞争酶联免疫吸附检测法的建立

本研究通过棋盘法优化替米考星抗体、包被原浓度,并考察了最佳包被条件,最佳反应温度、时间和酶标二抗最佳反应时间等,建立了替米考星残留的间接竞争酶联免疫吸附试验(ELISA)并应用到牛奶样本的检测。建立的间接竞争ELISA方法半数抑制浓度(IC₅₀)为2.1 ng/mL,牛奶中替米考星的最低检测限(LOD)为2 μg/L。在5、10和20 μg/L添加浓度下,回收率为79.2%~90.1%,变异系数不高于9.0%。与其他常见的大环内酯类药物无交叉反应。本研究建立的替米考星间接竞争ELISA方法灵敏度达到了残留限量标准要求,为开发可用于牛奶中替米考星的快速检测试剂盒奠定基础。     

GC法测定马香苓口服液中百秋李醇含量研究

试验旨在建立测定马香苓口服液中百秋李醇含量的研究方法。本研究采用气相色谱法,其色谱条件是使用色谱柱HP-5毛细管柱;柱温采用程序升温（初始温度150 ℃,保持18 min,以50 ℃/min速率升至280 ℃,保持5 min）;进样口温度为280 ℃;载气：高纯氮气;流速1 mL/min;进样量1 μL,分流比20：1;检测器为氢火焰离子化检测器,温度为280 ℃;氢气流速40 mL/min,空气流速370 mL/min;分别进行系统适用性试验、专属性试验、线性范围考察、检测限和定量限的确定、精密度试验、稳定性试验、重复性试验、加样回收率试验、耐用性试验,并对10批样品进行了含量测定。结果显示,专属性溶液中的溶剂峰、药液的杂质峰与主成分峰能达到有效分离且分离度符合要求（R ≥ 1.5）,表明该方法系统适用性良好;阴性对照溶液未检出色谱峰,表明样品中其他成分不干扰测定;百秋李醇定量限和检测限分别为2.842和0.812 μg/mL;百秋李醇检测质量浓度在15.86~1 015 μg/mL范围内与峰面积积分值呈良好的线性关系（y=0.869x-10.45,R²=0.999,n=7）。精密度试验、稳定性试验（日内和日间精密度）、重复性试验的平均RSD分别为0.90%、1.63%和1.83%、2.90%,其RSD均在可控范围内（RSD ≤ 3%）;平均加样回收率为95.36%,RSD=2.82%（n=6）,表明所建立的气相色谱法检测百秋李醇的含量回收率良好;进行耐用性试验,最终验证所建立的色谱方法可以稳定检测百秋李醇的含量。经方法学验证,该方法准确稳定,简便可行,能够作为马香苓口服液君药广藿香中百秋李醇的含量控制方法,同时也为该制剂质量控制提供了一种有效的检测方法,暂定本品中广藿香药材按百秋李醇计不少于47.53 μg/mL。     

HPLC法检测替米考星纳米内服混饮剂含量的方法学研究

为了验证检测替米考星纳米内服混饮剂中替米考星含量的高效液相色谱法(HPLC法)的方法学可靠性,试验用乙腈水(1∶1)200倍稀释替米考星纳米内服混饮剂,水浴10 min,12 000 r/min离心30 min,用磷酸稀释液稀释1 000倍;用Agilent SB C18(250 mm×4.6 mm×5μm)色谱柱,以865 mL超纯水、55 mL乙腈、55 mL四氢呋喃、25 mL磷酸二丁胺缓冲液为流动相,流速1.0 mL/min,检测波长280 nm,用HPLC法进行含量测定的方法学验证。结果表明:建立的替米考星纳米内服混饮剂含量测定的HPLC法标准曲线方程为:A=7 808.8C+2 314.6,R~2=0.999 9,替米考星在5～100μg/mL浓度范围内线性关系良好;平均回收率为(100.03±0.52)%,RSD为0.88%;日内稳定性的RSD为1.29%,日间稳定性的RSD为0.26%;样品平均含量为4.81%。表明所建立的方法专属性强、简便、可行,可用于替米考星纳米内服混饮剂中替米考星含量的测定。     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein     

Avian brood parasitism — a growing research area in behavioral ecology (part Ⅱ)

正We are pleased to publish the second special issue on avian brood parasitism and to be responsible guest editors for the two special issues of Chinese Birds (Vol. 3, No. 4, 2012 and Vol. 4, No. 1, 2013), entitled "Avian Brood Parasitism - A Growing Research Area in Behavioral Ecology". The first issue was published in December 2012. The goal of the two special issues is to publish accumulated knowledge and some of the recent developments in     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -