高效液相色谱法测定猪血浆中阿莫西林含量

建立了高效液相色谱法测定猪血浆中阿莫西林含量的方法.采用Agillent1100HPLC系统,色谱柱为SB C18,流动相为0.05 mol/L磷酸二氢钾-0.1 mol/L三乙胺-乙腈(800:120:7,pH 2.5),流速1.0 mL/min,柱温30℃,检测波长220 nm.猪血浆样品经高氯酸溶液变性处理,取上清液直接进样测定.阿莫西林的色谱峰面积对其浓度的线性关系范围在0.5～20.0μg/mL之间,相关系数为0.999 7.阿莫西林低、中、高(0.5,5.0,20.0μg/mL)三种添加浓度猪血浆样品的平均加样回收率分别为100.7%、105.1%、103.3%(n=3),变异系数分别为3.0%、0.1%、3.3%(n=3).该法可用于猪血浆中阿莫西林含量的测定和相关的药代动力学研究.     

RP-HPLC法测定阿莫西林-盐酸环丙沙星可溶性粉的含量

应用RP-HPLC法测定阿莫西林-盐酸环丙沙星可溶性粉的含量.采用Shim-pack CLC-ODS C18柱(150 mm×6 mm, 5 μm),以1.5×10-2 mol/L三乙胺溶液(用磷酸调pH至3.0)-乙腈 (体积比85∶ 15)为流动相,流速为1.0 mL/min,检测波长为229 nm,柱温为40 ℃.在此色谱条件下两者能完全分离,阿莫西林、盐酸环丙沙星分别在22～108 μg/mL和29～146 μg/mL范围内峰面积与浓度呈良好的线性关系,相关系数均为0.999 9.阿莫西林、盐酸环丙沙星的回收率分别为99.50%～100.20%和99.30%～99.86%(n=5);RSD分别为0.60%～1.00%和0.86%～1.02%(n=5).本法可用于阿莫西林-盐酸环丙沙星可溶性粉的质量控制.     

HPLC法测定阿莫西林胶囊中阿莫西林的含量

阿莫西林又名安莫西林或安默西林,分子式为C16H19N3O5S,是一种最常用的青霉素类广谱β-内酰胺类抗生素。固定相为:依利特hypersil BDSC18色谱柱(4.6*250*5u),乙腈-甲醇-0.1mol/L的磷酸二氢钾溶液-冰醋酸(10∶10:80:0.1)为流动相,检测波长为254nm;阿莫西林在100~350μg·m L-1范围内呈良好的线性关系。阿莫西林的平均回收率为99.5%。本法简便、重现性好、回收率高,可用于阿莫西林胶囊中阿莫西林的含量测定。     

鸡蛋中阿莫西林残留HPLC-DAD检测方法的建立

为了能够准确地测定鸡蛋中阿莫西林的残留,本试验建立了高效液相色谱-二级管阵列检测器(HPLC-DAD)方法来检测鸡蛋中阿莫西林残留。采用乙腈沉淀蛋白提取鸡蛋液中的阿莫西林,以超纯水饱和的二氯甲烷作为进一步萃取纯化的溶剂,0.01 mol/L磷酸二氢钾溶液(pH=5.5)和乙腈溶液为流动相,流速为1.0 mL/min,检测波长为230 nm,样品进样量为20μL,柱温为30℃的色谱条件对鸡蛋中阿莫西林残留进行检测。结果显示,阿莫西林的质量浓度范围为0.05～100.00μg/mL,与峰面积具有良好的线性关系(R²=0.999 8);该方法的重复性、精密度和稳定性均良好,相对标准偏差在2.0%以内;平均加样回收率介于82.89%～89.92%,相对标准偏差介于1.68%～2.71%;阿莫西林检测限为0.025μg/mL,定量限为0.050μg/mL。结果表明,本试验所建立的HPLC-DAD方法操作过程简便、稳定性好、灵敏度高,可适用于鸡蛋中阿莫西林残留的准确检测。     

HPLC法测定阿莫西林胶囊中阿莫西林的含量

阿莫西林又名安莫西林或安默西林,分子式为C16H19N3O5S,是一种最常用的青霉素类广谱β-内酰胺类抗生素。固定相为：依利特hypersil BDSC18色谱柱(4.6*250*5u ),乙腈-甲醇-0.1mol/L的磷酸二氢钾溶液-冰醋酸(10：10：80：0.1)为流动相,检测波长为254nm;阿莫西林在100~350μg·mL-1范围内呈良好的线性关系。阿莫西林的平均回收率为99.5%。本法简便、重现性好、回收率高,可用于阿莫西林胶囊中阿莫西林的含量测定。     

HPLC法同时测定芩黄颗粒中黄芩苷和甘草酸的含量

建立了高效液相色谱法(HPLC)同时测定芩黄颗粒中黄芩苷和甘草酸的含量。采用Agilent Eclipse XDB-C18(250 mm×4.6 mm,5μm)色谱柱,以乙腈-0.05%磷酸溶液为流动相,梯度洗脱,检测波长为252 nm,流速为1.0 mL/min。结果显示,黄芩苷和甘草酸的进样浓度分别在61.84~618.4、8.256~82.56μg/mL(R 2=0.9999,0.9999)范围内与峰面积呈良好线性关系;精密度、重复性和稳定性试验的RSD均小于2.0%;平均加样回收率分别为100.0%、99.2%,回收率的RSD分别为1.0%、0.6%(n=6)。本方法操作简便、准确,可用于芩黄颗粒中黄芩苷和甘草酸含量的同时测定。     

HPLC法同时测定复方吡喹酮浇泼剂中有效成分的含量

本试验旨在建立一种同时测定复方吡喹酮浇泼剂中吡喹酮和乙酰氨基阿维菌素含量的HPLC方法.色谱条件为 C18柱(250 mm×4.6 mm,5 μm),柱温30 ℃,流动相为乙腈-水-三氟乙酸(70:30:0.01),流速1.0 mL/min,进样量20 μL,检测波长245 nm.吡喹酮在0.7506~7.5063 mg/mL范围内,乙酰氨基阿维菌素在31.266~312.660 μg/mL范围内线性关系均良好,相关系数(r)均为0.9999,平均回收率分别为99.0%、98.1%,RSD分别为1.02%、0.32%.本试验所建立的HPLC法快速简便、准确可靠,可用于复方吡喹酮浇泼剂中吡喹酮和乙酰氨基阿维菌素含量的测定.     

UPLC-MS/MS法测定3种中兽药制剂中非法添加的阿莫西林和氨苄西林

应用超高效液相色谱-串联质谱技术,建立了3种中兽药制剂中非法添加阿莫西林和氨苄西林的检测方法。样品经50%乙腈水溶液提取、稀释后进行分析。实验采用0.2%甲酸乙腈溶液与0.2%甲酸水溶液作为流动相进行梯度洗脱,经Atlantis T3柱(2.1 mm×150 mm,5μm)分离,通过多反应监测模式进行测定。结果表明,阿莫西林和氨苄西林在1~50 ng/m L的范围内线性关系良好,最低检测限分别为0.5 mg/g和0.2 mg/g。阿莫西林回收率在83.4%~95.8%之间,RSD为2.0%~4.6%;氨苄西林回收率在85.1%~97.2%,RSD为1.7%~4.0%。本方法准确、可靠,可用于中兽药制剂中非法添加阿莫西林和氨苄西林的检测。     

HPLC法同时测定连花柴芩可溶性粉中4种有效成分含量

建立HPLC法同时测定连花柴芩可溶性粉中绿原酸、甘草苷、连翘酯苷A及黄芩苷的含量。采用Venusil XBP C18分析柱 (250 mm×4.6 mm,5 μm),以乙腈-0.1%磷酸水为流动相,1.0 mL/min的流速下进行梯度洗脱,320 nm波长处对4种成分进行含量测定。结果表明,在此色谱条件下,4种组分分离度良好,分别在3.28~26.24 μg/mL、3.17~25.36 μg/mL、6.08~48.64 μg/mL及8.81~70.48 μg/mL范围内线性关系良好,加样回收率均大于96.61 %,RSD均小于1.75 %。该方法简便、快速、准确,重复性良好,可用于连花柴芩可溶性粉中绿原酸、甘草苷、连翘酯苷A及黄芩苷的同时测定。     

超快速液相色谱法同时测定车前子中京尼平苷酸和毛蕊花糖苷的含量

建立超快速液相色谱法同时测定车前子中京尼平苷酸和毛蕊花糖苷的含量,为车前子药材的质量控制提供参考。采用Shim-Pack XR-ODS柱(75 mm×3.0 mm,2.2μm);流动相为0.1%甲酸水(A)-甲醇(B),梯度洗脱(0~11 min,20%~65%B),平衡时间为3 min;流速为0.4 mL/min;检测波长为254 nm;柱温为35℃。结果 :京尼平苷酸和毛蕊花糖苷分别在16-160μg/mL(R=0.9996)、8-80μg/mL(R=0.9995)浓度范围内与峰面积呈良好的线性关系;平均回收率(n=9)分别为99.0%和99.4%。结论:该方法结果准确、操作简便、具有良好的重现性和稳定性,可用于车前子药材的质量控制,同时为新兽药开发利用提供参考。     

Amoxycillin: clinical trials in dogs and cats

Amoxycillin, a new broad spectrum semi-synthetic penicillin was subjected to preliminary clinical testing in 351 cases in dogs and 264 in cats in veterinary practices. Two formulations were used: capsules by mouth and an aqueous suspension by injection. Those taking part were asked to use amoxycillin in the treatment of all conditions that they considered required an antibiotic and to report their results in terms of success or failure according to criteria laid down. Samples were taken whenever practicable for bacteriology. Dose ranges were 4 to 11 mg per kg for the oral capsules twice daily in dogs and most cats and 11 mg per kg once daily in some cat cases over five days and 2 to 7 mg per kg for the injectable suspension once daily in both species for three to five days. Results for the full range of conditions are given in tabulated form. Overall percentage of success according to the criteria laid down was 80.1%.     

Amoxycillin in the control of furunculosis in Atlantic salmon parr.

The efficacy of amoxycillin in the control of laboratory induced Aeromonas salmonicida infection in Atlantic salmon parr was investigated. When given in the diet at a dose rate of 80 mg per kg bodyweight it was effective against both a moderate and severe challenge (with mortality rates in untreated groups of 75 per cent and 45 per cent). At 40 mg per kg it was effective against the moderate challenge only. The plasma levels in these regimens were 1.25 micrograms per ml and 0.3 to 0.6 micrograms per ml and the minimum inhibitory concentration of the challenge strain of A salmonicida was 0.6 micrograms per ml. The potential of the Charm radiobioassay system in detecting antibiotic residues in fish tissue was studied. The level of amoxycillin in muscle and bone from fish in mid-treatment at 80 mg per kg was 0.32 micrograms per ml. After a 12 day withdrawal period at 18 degrees C no residue was detected within the 0.005 micrograms per ml limit of this test.     

Comparative Pharmacokinetics and Bioavailability of Amoxycillin in Chickens after Intravenous,Intramuscular and Oral Administrations

The pharmacokinetics and systemic bioavailability of amoxycillin were investigated in clinically healthy, broiler chickens (n = 10 per group) after single intravenous (i.v.), intramuscular (i.m.), and oral administrations at a dose of 10 mg/kg body weight. The plasma concentrations of amoxycillin were determined using high-performance liquid chromatography (HPLC) and the data were subjected to compartmental and non-compartmental kinetic analyses. Following single i.v. injection, all plasma amoxycillin data were described by a two compartment-open model. The elimination half-lives of amoxycillin were 1.07 h, 1.09 h and 1.13 h after single i.v., i.m. and oral administration, respectively. The total body clearance (Cl(B)) of amoxycillin was 0.80 (L/h)/kg and the volume of distribution calculated as V(d(area)) was 1.12 L/kg, respectively after i.v. administration. Substantial differences in the resultant kinetic data were obtained by comparing the plasma concentration profiles after i.m. injection with that after oral administration. The systemic i.m. bioavailability of amoxycillin was higher (77.21%) than after oral (60.92%) dosing. In vitro, the mean plasma protein binding of amoxycillin amounted to 8.27%. Owing to high clearance of amoxycillin in birds in our study, a plasma level was maintained above 0.25 microg/ml for only 6 h after i.m. and oral routes of administration and consequently frequent dosing may be necessary daily.     

Amoxycillin and clavulanic acid combination in the treatment of experimentally induced bacterial cystitis in cats

Clavulanic acid (CA) competitively inhibits beta-lactamase hydrolysis of penicillins in vitro. Treatment with amoxycillin combined with clavulanic acid (A-CA) was compared with placebo in a blind study in cats with experimental cystitis caused by Escherichia coli demonstrating in vitro resistance to amoxycillin. Bacterial cystitis was induced in 20 cats by bladder infusion of 5 ml of 0.05 per cent alcoholic salicylic acid followed after 24 hours by a brain-heart infusion broth of E coli (10(8) colony forming units ml-1) previously found to be resistant to amoxycillin in vitro (minimum inhibitory concentration over 512 micrograms ml-1). Four days after infection, cats were randomly divided into two groups of 10 and treated with amoxycillin combined with clavulanic acid or placebo for 10 days. When compared to the placebo-treated group, the A-CA treated group showed: reduced quantitative bacterial counts in urine on days 7 (P less than 0.001) and 14 (P less than 0.02); reduced culture positive urine on days 7 (P less than 0.001) and 14 (P less than 0.001); and less severe inflammation on histological examination of the bladder and urethra (P less than 0.01). It was concluded that A-CA was effective in reducing the bacterial count and reducing the histopathological changes in the bladder and urethra in an experimental model of acute bacterial cystitis in cats infected with an E coli demonstrating in vitro resistance to amoxycillin.     

Amoxycillin as an alternative to dihydrostreptomycin sulphate for treating cattle infected with Leptospira borgpetersenii serovar hardjo

Objective To assess the effect of amoxycillin treatment on urinary excretion of leptospires from cattle infected with Leptospira borgpetersenii serovar hardjo .
Design A chemotherapy trial with controls.
Procedure Fourteen heifers serologically negative to L hardjo were inoculated with L hardjo via the conjunctival route and assessed for evidence of infection by serological, fluorescent antibody and microbiological tests. Two injections (48 h apart) of amoxycillin at a dose of 15 mg/kg were administered intramuscularly to seven heifers 6.5 weeks after infection; the remaining heifers acted as untreated controls. Later, these seven control group heifers were treated with a single dose of amoxycillin (15 mg/kg). Samples of urine were collected before and after amoxycillin treatments; kidneys were collected at slaughter, and examined by fluorescent antibody test and microbiological culture.
Results Leptospires were isolated from the urine of 11 of 14 heifers inoculated with L hardjo . After treatment of six of these with two injections of amoxycillin, leptospires were not isolated. Of the controls, four of the five initially leptospiruric heifers continued to shed leptospires; after a single injection of amoxycillin, no leptospires were detected in the kidneys of these four.
Conclusion Amoxycillin may be an acceptable alternative to dihydrostreptomycin sulphate for the treatment of cattle infected with L hardjo .     

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.