兽药粉剂/预混剂中甲氧苄啶的测定

本文建立了HPLC测定兽药粉剂/预混剂中甲氧苄啶含量的方法。采用W aters C18色谱柱(150 mm×4.6 mm,5μm),流动相为甲醇-20 mmol/L磷酸二氢钾溶液(20∶80),流速1.0mL/m in,检测波长为271 nm,进样量为10μL。含量测定的线性范围为10~250μg/mL,r=1.0(n=6);甲氧苄啶的加样回收率在99.38%~100.6%之间;最低检出浓度为0.25μg/mL。结果表明本法简便、快速、准确、重复性好。     

HPLC-DAD法检测盐酸左旋咪唑注射液中左旋咪唑的含量

本研究建立了HPLC-DAD法测定盐酸左旋咪唑注射液中左旋咪唑含量的方法。采用Agilent Eclipse XDB-C18(250 mm×4.6 mm,5μm)色谱柱,流动相为0.05mol/L磷酸二氢钾溶液-乙腈(80∶20,v/v),流速为1.0mL/min,进样量为10μL,柱温为30℃,用二极管阵列检测器在190~400nm扫描,记录212nm波长处的色谱图。左旋咪唑在1~500μg/mL浓度范围内线性良好,相关系数为0.999 99。在2.5、5.0和10.0mg/g三个添加浓度下,加样回收率为99.1%~100.5%,RSD≤1.5%,检测限为2.5mg/g。本方法简便快捷,准确度和灵敏度高,可用于左旋咪唑注射液的质量控制。     

高效液相色谱法测定胆翘注射液中黄芩苷的含量

采用高效液相色谱法测定胆翘注射液中黄芩苷的含量[1]。色谱柱为Agilent Eclipse XDB-C18(5μm,250mm×4.6mm id),流动相为甲醇—水—冰乙酸(50∶50∶1),检测波长为274nm,流速1.0mL/min,柱温30℃。在相同的色谱条件下,探讨50%甲醇溶剂、流动相(50∶50∶1)对含量测定的影响,实验结果表明,不干扰黄芩苷含量结果测定(见图1、图2)。黄芩苷在0-100μg/mL浓度范围内线性关系良好R2=0.9999(n=6),回归方程为y=19.7840X+4.9103,回收率为97.6%~98.9%,相对标准偏差为0.5%。本方法简单、准确、可行,适用于胆翘注射液中黄芩苷含量测定。     

高效液相色谱法测定埃普利诺菌素注射液的含量

本文描述了用高效液相色谱法(HPLC)测定埃普利诺菌素注射液含量的方法研究。色谱条件:流动相为甲醇∶水(90∶10),流速1.0mL/min,进样量50μL,柱温为室温,检测波长245nm。样品回收率为(98.72±0.28)%。在5～200μg/mL浓度范围内,检测样品的中间精密度:批内变异系数为0.54%～0.80%,批间变异系数为0.28%～1.06%。本方法可用于埃普利诺菌素注射液的含量检测。     

高效液相色谱法测定双氯芬酸钠注射液的含量

目的:建立双氯芬酸钠注射液含量测定的高效液相色谱方法。方法:采用Ultimate LP-C_(18)-H色谱柱(5μm,4.6 mm×250 mm),甲醇-4%冰醋酸溶液(70∶30)为流动相,流速为1.0 mL/min,柱温30℃,检测波长为276 nm,采用外标法进行定量。结果:双氯芬酸钠的线性范围为5.03~503.40μg/m L,回归方程为Area=20.942×Amt1-54.805(n=5),相关系数大于0.999。从高(120%)、中(100%)和低(80%)3个添加水平的检测结果可以看出,双氯芬酸钠的回收率为98.17%~103.21%。结论:本方法可用于测定双氯芬酸钠注射液中双氯芬酸钠的含量。     

加米霉素注射液含量的高效液相色谱检测法的建立

为了建立加米霉素注射液含量的高效液相色谱检测法,为其检测提供依据,试验选用样品浓度为0.3 mg/mL,进样量为20μL,流速为1.0 mL/min,柱温为40℃,溶剂为乙腈,作为初步的色谱条件,比较不同比例流动相、不同色谱柱的峰形及分离效果,确定最优色谱条件,并考察该方法的线性关系、重复性、稳定性及添加回收率,并利用该方法对样品进行检测。结果表明:通过筛选确定了液相色谱检测条件,色谱柱为资生堂CAPCELL PAK C_(18) MGⅡ(250 mm×4.6 mm,5μm),流动相为磷酸盐缓冲液(取0.01 mol/L磷酸氢二钾溶液,用20%磷酸溶液调节pH值至8.0)∶乙腈(20∶80),检测波长为210 nm,流速为1.0 mL/min,柱温为40℃。用该条件进行检测,加米霉素标准品在1.714～450.0μg/mL范围内呈良好的线性关系(R~2=0.999 7);重复性试验平均含量为98.18%,相对标准偏差(RSD)为0.85%;在高、中、低3个水平下的回收率为98%～102%,平均回收率为99.71%,RSD为0.94%;用确定的液相色谱检测条件对8批中试样品的含量进行测定,结果RSD为0.23%。说明该方法重复性好、准确性高,可用于加米霉素注射液含量的检测。     

UPLC-PDA法测定甘草浸膏中甘草苷和甘草酸的含量

建立超高效液相色谱(UPLC)测定甘草浸膏中主成分甘草苷和甘草酸的含量。采用反相高效液相色谱法对甘草苷和甘草酸进行色谱分离和快速定量测定。以ACQUITY UPLC^TM T 3色谱柱(2.1 mm×100 mm,1.8μm)为分离柱,柱温:35℃;以乙腈-水(0.1%冰乙酸+5 mmol/L醋酸铵)进行梯度洗脱;流速:0.35 mL/min;进样量:1μL;检测波长为232 nm。通过光谱图、保留时间和峰面积参数对甘草苷和甘草酸进行定性定量检测。甘草苷在1~20μg/mL范围内线性关系良好(R^2>0.999),方法检出限为0.5μg/mL,定量限为1μg/mL;甘草酸在10~200μg/mL范围内线性良好(R^2>0.999),方法检出限为5μg/mL,定量限为10μg/mL,完全满足检测需求。该方法色谱分离较好,分析速度较快,前处理简单,适用于甘草浸膏中甘草苷和甘草酸的定性定量检测。     

HPLC法测定创伤愈合药喷雾剂中血竭素的含量

建立了高效液相色谱法测定创伤愈合药喷雾剂中血竭素含量的方法。色谱柱为C18柱(5μm,4.6 mm×250 mm),流动相乙腈-0.05 mol/L磷酸二氢钠溶液(50∶50),流速1.0 mL/min,柱温40℃,检测波长440 nm,血竭素在13.07～45.74μg/mL浓度范围内,峰面积与浓度线性关系良好(r=0.9997,n=6),平均加样回收率为98.29%,相对标准偏差为0.67%,血竭素的平均含量为0.01902 mg/mL。本研究所建立的含量测定方法简便、灵敏、准确、稳定,可用于创伤愈合药喷雾剂的质量控制。     

HPLC法测定中兽药散剂中非法添加的10种磺胺类药物

建立了中兽药散剂中非法添加10种磺胺类药物测定的高效液相色谱方法。液相色谱条件为:色谱柱C_(18)柱150 mm×4.6 mm(i.d.),5μm;流动相:乙腈-甲醇-2%乙酸溶液(15+5+80);流速:1.0 mL/min;柱温:30℃;检测波长:270 nm;进样量10μL。结果表明,10种磺胺类药物在50~800 ng/mL浓度范围内呈现良好线性关系,相关系数R~2均大于0.995,方法检测限为5μg/g,从5、10和20 mg/g 3个添加浓度检测结果可以看出,方法平均回收率为85.4%~106.8%(n=6),批内批间RSD均小于10%。     

高效液相色谱法测定猪血浆中氟苯尼考的含量

建立了猪血浆中氟苯尼考含量测定的高效液相色谱法(HPLC)。采用C18色谱柱(4.6mm×250mm,5μm),以乙腈-水(24:76)为流动相,流速1.0mL/min,检测波长223nm,进样量20μL,柱温为25℃。氟苯尼考浓度在0.1～16μg/mL时,标准曲线线性关系良好(r0.9998),无杂质干扰,回收率高于94%,批内变异系数和批间变异系数均低于5%。本方法操作简便,分析快速,结果准确,适用于猪血浆中氟苯尼考含量的测定及相关药代动力学研究。     

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.     

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     

Evaluation of the Microbiological Status of Milk and Various Structures in Mammary Glands from Naturally Infected Dairy Cows

A knowledge of the microbiological status of milk and of the different structures in the mammary glands has great importance in elucidating the pathogenesis of mammary gland infections. The objective of this study was to evaluate the microbiological status of various structures in the mammary glands from naturally infected dairy cows following slaughter. A total of 94 samples of milk, 184 samples of mammary parenchyma, 168 samples of gland cisterns, and 168 samples of teat cisterns were collected for microbiological examination. Microorganisms were detected in 59.9% of all samples, 67.0% of the milk samples, 70.1% of the mammary parenchymas, 55.9% of the gland cisterns and 48.8% of the teat cistern samples. When all samples were considered, coagulase-negative Staphylococcus were the most prevalent (35.7%) followed by coagulase-positive Staphylococcus (12.2%), Corynebacterium bovis (2.4%), Prototheca sp. (1.9%), and Streptococcus dysgalactiae (1.5%). There was a significantly higher occurrence of microorganisms in the milk and mammary parenchyma compared to the gland cisterns and teat cisterns. This revised version was published online in July 2006 with corrections to the Cover Date.     

Development and survival of free-living stages of gastrointestinal nematodes of sheep and goats on pasture in the Nigerian derived savanna

Four grass plots were sequentially contaminated with goat faeces containing known numbers of unembryonated eggs of predominantly Haemonchus contortus and Trichostrongylus spp. between October 1982 and April 1983. Four other plots were similarly contaminated with sheep faeces between February and May 1987. An additional plot was repeatedly contaminated with sheep faeces from February to April 1987. Populations of free-living stages in faeces and of infective larvae (L₃) in the herbage were subsequently monitored until the end of April and June of 1983 and 1987 respectively. During February and May 1987 two control cultures of sheep faeces were incubated in the laboratory at 25°C–30°C and at a constant temperature of 50°C and the free-living development was also monitored. L₃ developed very readily in the faeces cultured at 25°C–30°C and in those spread on a grass plot in October, at the end of the wet season, but developed less on the plot contaminated in May at the start of the wet season. Worm eggs in faeces deposited on plots during the hot dry season (December to April) or incubated at 50°C died and disintegrated after 24–48 h exposure to the high environmental temperatures. The results indicate that it is unlikely that gastrointestinal nematodes of sheep and goats can develop or survive on open pasture during the dry season in the Nigerian derived savanna zone.