高效液相色谱-串联质谱法检测猪肝中苯并咪唑类药物及其代谢物的残留量

建立了猪肝中阿苯哒唑及其代谢物阿苯哒唑砜、阿苯哒唑亚砜、2-氨基阿苯哒唑砜,噻苯哒唑及其代谢物5-羟基噻苯哒唑,甲苯哒唑及其代谢物氨基甲苯哒唑、5-羟基甲苯哒唑,芬苯哒唑及其代谢物芬苯哒唑砜、等效物奥芬哒唑,氟苯哒唑及其代谢物2-氨基-氟苯哒唑共14种苯并咪唑类药物及其代谢物残留检测的高效液相色谱-串联质谱方法。样品用乙酸乙酯提取,MCX固相萃取柱净化。Waters Xterra C18色谱柱(2.1 mm×150 mm,5μm)分离,流动相A相为0.1%甲酸乙腈溶液;B相为0.1%甲酸水溶液,梯度洗脱,外标法定量。结果表明,14种苯并咪唑类药物及其代谢物标准溶液在10~1 000 ng/mL的浓度范围内呈现良好的线性关系,R2均大于0.99,方法检测限为5μg/kg,定量限为10μg/kg,14种苯并咪唑类药物及其代谢物在10~200μg/kg添加浓度范围内回收率均70%~120%之间。批内、批间相对标准偏差均小于20%。本方法灵敏、准确,满足食品安全检测法规的要求。     

高效液相色谱法测定动物肌肉中的阿苯达唑及其代谢物

建立了动物肌肉组织中阿苯达唑及其代谢物阿苯达唑亚砜、阿苯达唑砜的多残留检测的高效液相色谱法。用乙酸乙酯提取肌肉组织样品中的药物,提取液浓缩后加入酸性乙醇和正己烷分配脱脂,过watersHLB固相萃取柱净化。以水-乙腈-甲酸为流动相,反相高效液相色谱紫外检测法检测。方法的平均回收率为86．4％,平均变异系数为1．96％。3种药物的检测限均为5μg／kg,定量限均为20μg／kg。     

牛肝中苯并咪唑类药物残留的高效液相色谱检测方法

建立了牛肝组织中苯并咪唑类药物(阿苯哒唑,噻苯哒唑和奥芬哒唑)多残留检测的高效液相色谱法.用乙酸乙酯提取牛肝组织样品中的药物,提取液浓缩后加入酸性乙醇和正己烷分配脱脂,过C18固相萃取柱净化.以甲醇-磷酸二氢铵缓冲液为流动相,反相高效液相色谱紫外检测法检测.方法的平均回收率为78.8%,平均变异系数为2.18%.3种药物的检测限为8 μg/kg,定量限为25 μg/kg.     

高效液相色谱法测定鸡肉中氟苯哒唑、噻苯哒唑及其代谢物残留量

采用高效液相色谱-紫外分光法测定鸡肉中氟苯哒唑、噻苯哒唑及其代谢物残留量,结果表明,氟苯哒唑、噻苯哒唑及其代谢物在20～1 000ng/ml浓度范围内,呈现良好的线性关系(相关系数R~20.999 90)。在20～400μg/kg范围内平均回收率为70.00%～92.14%,批内RSD均小于8.59%,批间RSD均小于10.28%,该方法的加标回收率和精密度试验结果较好,因此,该法可用于鸡肉中氟苯哒唑、噻苯哒唑及其代谢物残留量测定。     

高效液相色谱法检测羊鸡组织中氟苯达唑、噻苯达唑及其代谢物残留量的研究

建立了一种可同时检测羊组织（肌肉、肝脏、肾脏、脂肪）、鸡组织（肌肉、肝脏）中氟苯达唑及代谢物2-氨基氟苯达唑、噻苯达唑及代谢物5-羟基噻苯达唑药物残留的高效液相色谱检测方法。结果表明：氟苯达唑及代谢物2-氨基氟苯达唑、噻苯达唑及代谢物5-羟基噻苯达唑在0.02～1.5μg/mL浓度范围内呈良好的线性关系r,均大于0.999。方法的定量限为20μg/kg。在鸡组织（肌肉、肝脏）中,两种药物及其代谢物在20～800μg/kg的添加浓度范围内,其回收率范围在60%～100%之间;在羊组织（肌肉、肝脏、肾脏、脂肪）中,两种药物及其代谢物在20～200μg/kg的添加浓度范围内,其回收率范围在60%～100%之间;批内变异系数均小于15%、批间变异系数均小于20%。     

化学药物对家禽的有害作用(下)

五、驱蠕虫剂1.苯并咪唑类药物(Benzimidazoles)噻苯咪唑及其衍生物、苯咪氨甲酯、苯硫哒唑和甲苯咪唑,对寄生虫的作用方式可能相同。噻苯咪唑可干扰寄生虫体延胡索酸盐还原酶,从而干扰作为寄生虫能量来源的无氧酵解作     

芬苯哒唑长效控释丸在山羊体内的药物动力学研究

本试验用反相高效液相法测定芬苯哒唑长效控释丸在山羊体内的药物动力学。在血浆中测到芬苯哒唑代谢产物亚砜和砜，其平均浓度分别为７．１７±１．５４ｍｇ／ｍｌ和３．８６±１．０３ｎｇ／ｍｌ，但未测出原药浓度。在瘤胃液中测出的芬苯哒唑平均浓度为２１９．００±１３０．８３ｎｇ／ｍｌ。结果表明芬苯哒唑长效控释九可以在山羊体内恒定释放药物１１０天以上。     

液相色谱-串联质谱法检测牛奶中苯并咪唑类药物

应用液相色谱-串联质谱法检测牛奶中的苯并咪唑类药物。经试验,14种苯并咪唑类药物及其代谢物在10~1 000 ng/m L的浓度范围内呈现良好的线性关系,R2均大于0.99;检测限可达到5μg/kg,定量限能达到10μg/kg;采用该方法,在10,50,100,200μg/kg添加浓度范围内,牛奶中苯并咪唑类药物及其代谢物的回收率均在70%~120%范围内;批内相对标准偏差均≤20%,批间相对标准偏差均≤20%,符合要求。     

超高效液相色谱-串联质谱法检测饲料中4种硝基咪唑类药物

建立了同时检测饲料中洛硝哒唑、甲硝唑、二甲硝唑、替硝唑4种硝基咪唑类药物的超高效液相色谱-串联质谱法。样品经乙酸乙酯提取,Oasis MCX柱净化,以0.1%甲酸水-乙腈溶液为流动相梯度洗脱进行液相色谱-串联质谱检测。在10、50、100μg/kg的添加浓度下,饲料中各药物的回收率为70.3%～96.0%,相对标准偏差为4.2%～8.7%。检测限为3μg/kg,定量限为10μg/kg。     

超高效液相色谱-串联质谱法测定牛奶中三氯苯哒唑及其代谢物残留量的研究

建立了牛奶中三氯苯哒唑及其代谢物三氯苯唑酮残留量的超高效液相色谱-串联质谱（UPLC-MS/MS）测定方法。样品经乙酸乙酯提取后,正己烷除脂,经超高效液相色谱仪和C18色谱柱分离,以乙腈和5mmol/L乙酸铵溶液为流动相进行梯度洗脱。加热电喷雾负离子模式（HESI—）电离,选择反应监测模式（SRM）检测,外标法定量。结果表明：三氯苯哒唑和三氯苯哒唑酮标准溶液在5～500μg/L范围内呈现良好的线性关系,r2＞0.99,方法检测限为1μg/kg,定量限为2μg/kg。三氯苯哒唑和三氯苯唑酮在2～10μg/kg添加水平范围内的回收率为72.3%～110%,批内和批间变异系数均小于13.5%。该方法具有简便快捷、灵敏度高、准确度高等优点。     

Pharmacokinetics of albendazole sulfoxide enantiomers administered in racemic form and separately in rats

The pharmacokinetic behaviour of albendazole sulfoxide (ABZSO) enantiomers was studied in rats after the oral administration of 10 mg/kg of rac-ABZSO, 5 mg/kg of (-)-ABZSO or 5 mg/kg of (+)-ABZSO. The disposition profiles of ABZSO enantiomers were similar in all treatments, but the calculated area under the curve for the (-)-ABZSO was higher in all cases compared with (+)-ABZSO. The results suggest that there is no chiral inversion of ABZSO enantiomers. After the administration of rac-ABZSO, 17.2% of the total dose was recovered in urine as albendazole ABZ (0.1%), albendazole sulfone ABZSO(2) (0.3%), albendazole 2-aminosulfone (ABZ-SO(2)NH(2)) (3.1%) and ABZSO (13.7%). The ratio (+) to (-) was similar in urine (1.6) and blood (1.7).     

Modulations of bovine hepatic microsomal metabolism of benzimidazoles by secondary plant metabolites

The study was aimed to estimate the effect of plant secondary metabolites present in ruminants diet and phytogenic feed additives on liver microsomal metabolism of albendazole and fenbendazole. The selected phytocompounds comprised of flavonoids (apigenin, quercetin) and saponins (hederagenin, medicagenic acid). The experiments were performed on liver microsomal fraction obtained from routinely slaughtered cows. The intensity of albendazole and fenbendazole metabolism in the presence of flavonoids and saponins was analyzed in equimolar concentration (100 μM). The obtained results revealed that both flavonoids and saponins intensify the metabolism of albendazole and fenbendazole in bovine microsomes. In the case of albendazole, apigenin and quercetin doubled the amount of degraded drug and the amount of produced albendazole sulfoxide. Additionally, both flavonoids increased the amount of produced albendazole sulfone. Saponins, hederagenin, and medicagenic acid intensified the degradation of albendazole (1.8‐fold) and the production of albendazole sulfoxide (twofold). Medicagenic acid inhibited the production of albendazole sulfone. In the case of fenbendazole, the degradation of the drug and the production of oxfendazole were increased four and five times in the presence of saponins and flavonoids, respectively. The enhancement of benzimidazoles’ metabolism caused by the studied plant metabolites could change pharmacokinetics and the efficacy of benzimidazoles’ treatment in cattle.     

In vitro sulfoxidation of albendazole by ovine liver microsomes: assay and frequency of various xenobiotics

The in vitro biological oxidation of albendazole to its pharmacologically active sulfoxide and its sulfone by ovine liver microsomes has been studied. Sulfoxidation (maximal rate = 0.412 nmole/min/mg of protein, Michaelis constant = 185 X 10(-6) M) was 107 times more potent than formation of albendazole sulfone. The sulfoxidation corresponds to a reduced nicotinamide-adenine dinucleotide phosphate-dependent enzymatic system characterized by a pH optima value around 8. Flavin adenine dinucleotide-containing monooxygenase could be responsible for this S-oxygenation because of the strong inhibitory effect of methimazole. Albendazole sulfoxidase is inhibited competitively by the related anthelmintic drug fenbendazole (inhibitory constant = 243 X 10(-6) M) and noncompetitively by chlorpromazine (inhibitory constant = 135 X 10(-6) M). At high concentration, chloramphenicol, erythromycin, nalidixic acid, and hexobarbital are less active inhibitors, whereas dexamethasone acetate significantly enhances the reaction which is not inhibited by either carbon monoxide, griseofulvin, imidazole, phenylbutazone, or proadifen.     

Metabolite concentrations in plasma following treatment of cattle with five anthelmintics

Plasma concentrations of anthelmintics and their metabolites were determined after cattle were treated at recommended dose rates and routes of administration. Fenbendazole, oxfendazole, febantel, albendazole and thiabendazole were given orally and oxfendazole was also administered with an intraruminal injector. After fenbendazole, oxfendazole and febantel were administered, fenbendazole, oxfendazole and fenbendazole sulphone were all detected in plasma in each case. However, there were marked differences between the three anthelmintics in the peak concentrations and areas under the plasma concentration/time curve (AUC) of these three metabolites. Intraruminal administration of oxfendazole produced higher AUC for fenbendazole and fenbendazole sulphone than did oral administration. Albendazole sulphoxide and sulphone were detected in cattle plasma after albendazole administration but no parent drug was present. These metabolites disappeared more rapidly in cattle than has been reported for sheep. Only 5(6)hydroxythiabendazole was detected in cattle plasma after thiabendazole treatment.     

Effects of an anthelmintic treatment programme on sheep productivity in the Middle Atlas,Morocco

Summary This study evaluated the production advantages of the strategic anthelmintic treatment of both lambs and ewes in an area endemic for gastro-intestinal nematodes, lungworms and liver flukes. The liver fluke infections were generally chronic. The lambs were treated with albendazole (SmithKline Beecham), fenbendazole (Hoechst Roussel) or a vitamin supplement and their weight gains were followed over the next 7 months. The control group, which received a vitamin supplement only, gained 6·67 kg from July to January. The group that received fenbendazole, an anthelmintic with no activity against liver flukes, gained 10·42 kg over the study period. The third group which received albendazole, an anthelmintic with efficacy against liver flukes, gained 13·07 kg over the same period. Lamb deaths apparently due to liver flukes were 12, 4, and zero for the control, fenbendazole and albendazole groups, respectively. Similar advantages were observed in the ewes. Deaths were 16, 8, and zero in the control, fenbendazole and albendazole groups, respectively. The lambing rate in the control groupswas significantly lower than that in either of the 2 treated groups. The number of services per conception was significantly lower in the albendazole treated group than that in either of the other groups. These studies demonstrated the advantages of anthelmintic treatment in sheep in a helminth endemic area. While removing gastro-intestinal nematodes and lungworms improved production, the additional removal of liver flukes enhanced production gains as well as reducing deaths.

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Resumen Este estudio evaluó las ventajas de un tratamiento estratégico en corderos y ovejas en un área endémica de parásitos gastrointestinales, pulmonares y hepáticos. La infección con fasciola era crónica. Los corderos fueron tratados con albendazole (Smithkline Beecham), fenbendazole (Hoechst Roussel) o un suplemento vitamínico; el peso fue consignado durante 7 meses seguidos. El grupo control que recibió el suplemento vitamínico, ganó 6·67 kg desde julio hasta enero. El grupo que recibió fenbendazole, antihelmíntico sin acción contra la fasciola, ganó 10·42 kg durante el período de estudio. El tercer grupo que recibió albendazole, un antihelmíntico eficaz contra la fascioliasis, ganó 13·7 kg durante el mismo período. La mortalidad de los corderos aparentemente debida a fascioliasis fue de 12 animales, 4 animales y cero animales, en el grupo control, en el tratado con fenbendazole y en el tratado con albendazole, respectivamente. En ovéjas, las ventajas fueron similares. La mortalidad por fascioliasis fue de 16 animales, 8 animales y cero animales, en el grupo control, en el tratado con fenbendazole y en el tratado con albendazole, respectivamente. La tasa de pariciones en el grupo control, fue significativamente más baja, que aquella de los grupos tratados. El número de servicios por concepción fue menor en el grupo tratado con albendazole. Estos estudios demostraron, la ventaja de los tratamientos antihelmínticos en ovejas en áreas endémicas. Mientras que el tratamiento contra parásitos gastrointestinales y pulmonares mejoró la producción, el tratamiento contra fasciola mejoró las ganancias de peso y redujo las muertes.

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Résumé Cette étude évalue les avantages en matière de production d’une stratégie de traitements anthelminthiques des brebis et des agneaux dans une zone endémique pour les nématodes gastro-intestinaux, les Fasciola et les strongles pulmonaires. Les infections à Fasciola ont généralement un caractère chronique. Les agneaux ont été traités soit à l’albendazole (SmithKline, Beecham) ou au fenbendazole (Hoechst Roussel) ou avec un complément vitaminé. Leur gain de poids ont été suivis pendant les sept mois suivants. Le groupe des témoins qui n’a re?u qu’un complément vitaminé a gagné 6,67 kg de juillet à janvier. Celui traité au fenbendazole, anthelminthique dépourvu d’activité contre les douves a progressé de 10,42 kg pendant la période d’étude. Le troisième groupe a été traité à l’albendazole, produit actif contre les Fasciola. Il a gagné quant à lui 13,07 kg au cours du même laps de temps. La mortalité des agneaux, due apparemment aux douves a été pour les groupes témoins et fenbendazole et albendazole respectivement de 12,4 et zéro. Des avantages identiques ont été observés pour les brebis dont la mortalité a été de 16,8 et zéro respectivement pour les lots témoins et fenbendazole et albendazole. Le taux d’agnelage dans le groupe témoin a été significativement plus bas que celui de l’un et de l’autre des deux groupes traités. Le nombre d’accouplements par conception était significativement plus bas dans le lot traité à l’albendazole que dans n’importe lequel des autres lots. Ces facteurs confirment les avantages d’un traitement anthelminthique chez les ovins vivants dans une région de parasitisme endémique. Tandis que la production est améliorée par la suppression des nématodes gastro-intestinaux et des strongles pulmonaires, la disparition complémentaire des douves accro?t les gains de production au même titre qu’elle réduit la mortalité.

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This work was supported in part by the International Foundation for Science (Stockholm).     

The efficacy of fenbendazole and albendazole against immature and adult stages of benzimidazole-resistant sheep trichostrongylids

The efficacy of two recently introduced benzimidazole anthelmintics, albendazole and fenbendazole, was determined for six-day, 10-day and adult stages of resistant strains of Haemonchus contortus and Trichostrongylus colubriformis. Albendazole, at 3.8 mg/kg reduced H contortus worm counts by 92.4, 70.8 and 67.1 per cent while fenbendazole, at 5.0 mg/kg, reduced worm burdens by 51.7, 95.5 and 93.4 per cent against six-, 10- and 25-day-old parasites respectively. For T colubriformis, the corresponding reductions with albendazole were 97.7, 95.8 and 64.9 per cent and for fenbendazole 29.0, 66.3 and 33.4 per cent. Compared with susceptible strains of H contortus and T colubriformis, for which therapeutic doses of benzimidazole anthelmintics are generally highly active against all stages of development, the present results show that these drugs do not have a uniform level of activity against all developmental stages of resistant strains.     

The oxidative metabolism of fenbendazole: a comparative study

The oxidative metabolism of fenbendazole (FBZ) was studied in hepatic fractions prepared from livers of cattle, sheep, goats, chickens, ducks, turkeys, rats, rabbits and catfish. All species produced the sulfoxide metabolite (oxfendazole; FBZ-SO), and p-hydroxyfenbendazole (FBZ-OH) was produced by all species except sheep. The product of demethoxycarbonylation, fenbendazole amine (FBZ-NH2), was not produced by liver preparations of any species. A fourth metabolite, resulting from the further oxidation of oxfendazole, fenbendazole sulfone (FBZ-SO2), was formed in all species but at highly varying rates. The chicken exhibited the highest overall rate of FBZ metabolism, followed by the duck, goat, sheep, steer, catfish, rat, rabbit, and turkey. Considerable variation was evident among avian species, the duck and turkey produced substantially less of the FBZ-OH and FBZ-SO2 metabolites than the chicken. Catfish liver preparations formed equivalent amounts of metabolite at 25 degrees C and 37 degrees C incubation temperatures. The formation of the sulfone metabolite (FBZ-SO2), however, was practically nonexistent in catfish.     

Bioavailability of albendazole sulphoxide after netobimin administration in sheep: effects of fenbendazole coadministration.

After oral co-administration of two dosages of netobimin (7.5 and 20 mg kg-1 with fenbendazole (1.1 mg kg-1) to Merino sheep, the AUC0-infinity of albendazole sulphoxide at the lower dosage of netobimin, was significantly increased (75.5 per cent) from control value (34.43 +/- 7.91 versus 60.33 +/- 11.93 microg h ml-1). The pharmacokinetic parameters MRT and T1/2 were also increased: 18.96 +/- 2.54 vs 26.44 +/- 4.69 h and 10.31 +/- 1.72 vs 22.28 +/- 6.75 h respectively. No data corresponding to the higher dosage of netobimin (20 mg kg-1) were statistically different from control values. It is concluded that fenbendazole increases the bioavailability of albendazole sulphoxide in sheep at the 7.5 mg kg-1 dosage, and this may produce a potentiated anthelmintic action.     

Multiple anthelmintic resistance in Haemonchus contortus on a sheep farm in India

Multiple resistance to benzimidazoles (fenbendazole, albendazole and mebendazole) in a strain of Haemonchus contortus in sheep was detected on a farm where fenbendazole resistance had already been identified. Following a faecal egg count reduction test, this was confirmed by both critical and controlled anthelmintic tests. Different groups of sheep infected naturally or given an experimental infection with the fenbendazole-resistant strain were treated with the recommended doses of various anthelmintics. Compared to the control group, percentage reductions in faecal egg counts of sheep treated with fenbendazole, albendazole, mebendazole, levamisole and morantel varied between 56% and 81% and worm counts between 71% and 86%. The results indicate the presence of multiple anthelmintic resistance in this strain of H. contortus on this farm. Sheep treated with ivermectin and closantel showed 100% reductions in faecal egg and worm counts, suggesting high efficacy of these drugs against the population of H. contortus on this farm.     

Naphthalophos combinations with benzimidazoles or levamisole as effective anthelmintics for sheep

Objective: To investigate the relative efficacy and safety of the anthelmintic naphthalophos in sheep, either given alone or in combination with benzimidazole (fenbendazole and albendazole) or levamisole anthelmintics.
Design: A parasitological study using faecal egg count reduction tests, a validating slaughter trial and field safety trials.
Procedure: Faecal egg count reduction tests were carried out on 13 farms. Naphthalophos and combinations of naphthalophos with levamisole and fenbendazole were included in the drench tests. On one property a controlled efficacy study was carried out to validate faecal egg count reduction test findings. In this trial, sheep were slaughtered 10 days after treatment and the remaining parasites recovered from the gastro-intestinal tract. Safety trials were carried out on eight farms where approximately 50 000 sheep were treated with naphthalophos and albendazole that were tank mixed in the backpack.
Results: The efficacy of naphthalophos alone in faecal egg count reduction tests ranged from 59 to 98% with one test showing 95% reduction. The efficacy of naphthalophos and levamisole ranged from 74 to 100%, with 5 farms showing 95% reduction. The efficacy of naphthalophos and fenbendazole ranged between 88 and 100% with 95% reduction achieved on 10 farms. The controlled efficacy study showed a good correlation between the faecal egg count reduction tests and numbers of parasites recovered, except for Nematodirus where the faecal egg count reduction tests overestimated efficacy. The mortality rate in the safety trials was 0.05%, with most fatalities occurring on one farm.
Conclusion: The combination of naphthalophos and fenbendazole was more effective than a combination of naphthalophos and levamisole, and will provide a sufficiently safe drench rotation option.