摘要:

Sanyal, P.K. Pharmacokinetic behaviour of fenbendazole in buffalo and cattle.J. vet. Pharmacol. Therap.17, 1–4.Concentrations of fenbendazole and of drug metabolites in plasma were measured in buffalo and cross‐bred cattle after single intraruminal administration at two different doses. Plasma concentrations of the parent compound fenbendazole and the two metabolites, viz. oxfendazole and fenbendazole sulfone, were much lower in buffalo compared with cattle, at a dose of 7.5 mg/kg body weight as indicated by lower area under concentration curve and concentration maximum. At a dose of 15 mg/kg body weight there were corresponding increases in plasma metabolite concentrations in cattle. However, buffaloes did not show a similar corresponding incre

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1994.tb00513.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Pedersoli, W.M., Ravis, W.R., Jackson, J., Shaikh, B. Disposition and bioavailability of neomycin in Holstein calves.J. vet. Pharmacol. Therap.17, 5–11.The disposition and absorption kinetics of neomycin were studied in healthy ruminating dairy calves (n‐6), approximately 3‐months‐old. The calves were treated with single intravenous (i.v.) (12 mg/kg), intramuscular (i.m.) (24mg/kg), oral (p.o.) (96 mg/kg) and repeated p.o. (96 mg/kg, b.i.d., 15½ days) doses of neomycin. A 3‐week rest period was allowed between treatments A and B and B and C Baseline and serial venous blood samples were collected from each calf plasma concentrations of neomycin were determined by a high performance liquid chromatography procedure. The resulting data were evaluated by using compartmental pharmacokinetic models and nonlinear least squares regression analysis. The mean of some selected parameters weret½λ3 7.48 ± 2.02 h, Clt= 0.25 ± 0.04 L/h/kg,Vd(ss)= 1.17 ± 0.23 L/kg, andMRT =4.63 ± 0.87 h for the i.v. data andt½= 11.5 ± 3.8 h,MRTabs= 0.960 ± 1.001 h, F = 127 ± 35.2%, andClt/F= 0.199 ± 0.047 L/h/kg for the i.m. data, respectively. Only one calf absorbed neomycin to any significant degree (F = 0.0042) after a single p.o. dose. Selected mean parameters determined after repeated oral dosing were: F = 0.45 ± 0.45%, Cmax= 0.26 ± 0.37m̈g/ml, and tmax= 2.6 ± 2.9 h. Terminal half‐lives determined for the i.v. and i.m. treatments were considerably longer than those reported p

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1994.tb00514.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abdennebi, E.H., Khales, N., Sawchuk, R.J., Stowe, CM. Thiamphenicol pharmacokinetics in sheep.J. vet. Pharmacol. Therap.17, 12–16.The pharmacokinetics of thiamphenicol were investigated after intravenous (i‐v.). intramuscular (i.m.) and oral (p.o.) administration to sheep. It was found that the drug is almost completely absorbed following intramuscular injection, with a bioavailability of about 8 7.5%. Thiamphenicol appears to be widely distributed into extravascular compartments, yielding a volume of distribution [V(b)] of approximately 1 1/Kg. Elimination from the blood is relatively rapid, with a biological half‐life of about 1.5 h. Oral treatment showed that thiamphenicol is absorbed from the gastrointestinal tract yielding very low plasma concentrations which were maintained for at least 24 h. Although only 30% of the oral dose was systemically available, in contrast to chloramphenicol, thiamphenicol is truly absorbed when given orally to adult sheep. One possible reason for this observation is that rumen flora do not biotransform this drug as they do for chloramphenicol. Metabolism investigations are, however, needed to confirm this fi

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1994.tb00515.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Ewing, P. J., Burrows, G., MacAllister, C, Clarke, C. Comparison of oral erythromycin formulations in the horse using pharmacokinetic profiles.J. vet. Pharmacol, Therap.17, 17–23.The pharmacokinetic properties of four erythromycin formulations were compared in six adult horses after administration of single and multiple oral doses. Formulations of erythromycin administered were estolate and phosphate given 37.5 mg/kg every 12 h and 25 mg/kg every 8 h, and stearate and ethylsuccinate given 25 mg/kg every 8 h. Areas under the curve (AUC) and maximum plasma erythromycin concentrations (Cmax) were equal or greater (P ≥ 0.05) following administration of erythromycin phosphate and stearate compared with those values following administration of erythromycin estolate or ethylsuccinate. In comparing an 8 h vs. a 12 h dosage interval for multiple doses of erythromycin phosphate or estolate, there were no significant differences observed in AUC(24–28 h), peak‐trough plasma concentrations or duration that plasma concentrations exceeded the minimal inhibitory concentration (MIC) forRhodococcus equi.Comparisons of pharmacokinetic parameters between single and multiple doses were made for each formulation. Differences in Cmax, tmax, ort½β between single and multiple doses were demonstrated for erythromycin ethylsuccinate and estolate. Based on equivalent plasma antibiotic concentrations, erythromycin phosphate or stearate could be substituted for estolate in the treatment ofRhodococcus equipneumonia. Furthermore, there was no advantage of an 8‐h interval, compared with an inter

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1994.tb00516.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Jaglan, P.S., Roof, R.D., Yein, F.S., Arnold, T.S., Brown, S.A., Gilbertson. T.J. Concentration of ceftiofur metabolites in the plasma and lungs of horses following intramuscular treatment.J. vet. Pharmacol Therap. 17, 24–30.Ceftiofur sodium, a broad spectrum cephalosporin antibiotic approved for veterinary use, is metabolized to desfuroylceftiofur which is conjugated to micro as well as macromolecules. Twelve horses, weighing 442–618 kg, were injected intramuscularly with a single dose of 2.2 mg ceftiofur/kg (1.0 mg/lb) body weight. Blood was collected at various intervals over 24 h after treatment. Three groups of four horses each were euthanized and lungs were collected at 1,12, and 24 h after treatment.The concentration of desfuroylceftiofur and desfuroylceftiofur conjugates in the plasma and lungs was determined by converting them to desfuroylceftiofur acetamide (DCA) and measured DCA by high performance liquid chromatography with UV detection. The average maximum concentration (Cmax) of desfuroylceftiofur and related metabolites in plasma expressed as ceftiofur equivalents was 4.46 ± 0.93m̈g/ml occurred at 1.25 ± 0.46 h after treatment. These concentrations declined to 0.99 ± 0.16, 0.47 ± 0.15 and 0.17 ± 0.02m̈g/ml at 8, 12, and 24 h, respectively. The mean residence time of ceftiofur metabolites was 6.10 ± 1.27 h.Concentration of desfuroylceftiofur and desfuroylceftiofur conjugates in the lungs of horses expressed as ceftiofur equivalents were 1.40 ± 0.36, 0.27 ± 0.07, and 0.15 ± 0.08m̈g/ml at 1, 12, and 24 h, respectively. These concentrations of the drug at 12 and 24 h in lung homogenate were similar but slightly lower than plasma concentrations in the same horses, and the plasma pharmacokinetic values including half‐life were similar to those observed at the approved dose of 1.1–2.2 mg ceftiofur/kg body weight administered intramuscularly once daily for

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1994.tb00517.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Gagnon, H., Ferguson, J.G., Papich, M.G., Bailey, J.V. Single‐dose pharmacokinetics of cefazolin in bovine synovial fluid after intravenous regional injection.J. vet. Pharmacol. Therap.17, 31–37.The pharmacokinetic properties of cefazolin in the synovial fluid of the tibiotarsal joint were determined in 10 healthy mature cattle after intravenous regional injection of 2 50 mg cefazolin. A pneumatic tourniquet was positioned proximal to the tibiotarsal joint and the intravenous injection was performed distal to the tourniquet. Synovial fluid concentrations of cefazolin increased in the first 30 mm and fluctuated between 54.7 ± 11.0m̈g/ml (mean ± SEM) and 73.2 ± 13.2m̈g/ml in the following 90 min while the tourniquet remained inflated. After tourniquet removal, synovial fluid concentration‐time curves followed first‐order one‐compartment model decay in most of the animals with an elimination half‐life of 0.82 h (harmonic mean). Therapeutic concentrations of cefazolin in the synovial fluid of normal joints were reached and this injection technique could be used as an alternative to systemic administration of antibiotics to provide adequate concentrations in

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1994.tb00518.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Schoevers, E.J., Terlou, M., Pijpers, A., Verheijden, J.H.M. An image analysis system: an objective and accurate alternative for reading the agar diffusion test.J. vet. Pharmacol Therap.17, 38–42.A computerized image analysis system (IAS) has been used to develop a new method for reading the agar diffusion test automatically. In four experiments a total of 88 porcine plasma and 95 urine samples were screened for oxytetra‐cycline by the agar diffusion test. The inhibition zones were measured by hand and by the IAS directly from the bioassay plate and by the IAS from the photonegative taken from the plate. Both methods were positively correlated with the hand method for plasma (0.9716, 0.9669) and urine (0.9878, 0.9731) in the range tested for 0.1 to 2.0 (m̈/ml. Moreover, the coefficient of variation and the day‐to‐day‐variation amounted to 1,72% and 1.47% respectively, for the method by hand and 1.10, 1.54% and 0.27, 0.38% respectively, for the IAS methods. It is concluded that the IAS method is an objective and accurate alternative for reading the agar diff

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1994.tb00519.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Deleforge, J., Thomas, E., Davot, J.L., Boisrame, B. A field evaluation of the efficacy of tolfenamic acid and oxytetracycline in the treatment of bovine respiratory disease. J. vet. Pharmacol Therap. 17,43–47.In ablinded multicentre trial 313 cattle showing clinical signs of respiratory disease were allocated randomly into three groups, treated intramuscularly with a long‐acting oxytetracycline formulation at a dose rate of 20 mg/kg bodyweight in combination with vehicle alone (placebo) or with tolfenamic acid at 2mg/kg, bodyweight once or on two occasions with a 48‐h interdosing interval. The clinical status of the animals was monitored for 5 days using a specific scoring system and weight gain was calculated between day 0 and day 21. Relapses were monitored from day 5 until day 21. When oxytetracycline was combined with two injections of tolfenamic acid, there was a significant (P<0.04) improvement in the clinical resolution. This regimen also produced non‐significant improvements in cure rate, reduced frequency of relapses and improved weig

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1994.tb00520.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

A/Hadi, A.A., Wasfi, I.A., Gadir, F.A., Amiri, M.H., Bashir, A.K. Baggot, J.D. Pharmacokinetics of tobramycin in the camel. J. vet. Pharmacol. Therap.17. 48–51.The pharmacokinetics of tobramycin were determined in six healthy camels(Camelus dromedarius)following the intravenous (i.v.) and intramuscular (i.m. administration of single doses of tobramycin sulphate (40 mg/ml). The half‐life to tobramycin was 189 ± 21 min and the mean residence time was 254 ± 26 min. The apparent volume of distribution (area method) was 245 ± 21 ml/kg. while volume of the central compartment of the two‐compartment pharmaco‐kinetic model was 110 ± 12 ml/kg. The clearance (systemic) of tobramycin was 0.90 ± 0.10 ml/min/kg. Values of the pharmacokinetic parameters suggest that glomerular filtration rate is lower in camels than in other ruminant species, horses, dogs and cats. Following i.m. administration of the dose (1.0 mg/kg), the drug was rapidly absorbed with peak serum concentration of 3.32 ± o.59m̈g/ml at 20–30 min; the absorption half‐life was 3.9 ± 0.9 min. The systemic availability of tobramycin was 90.7 ± 14.4%. The apparent half‐life was 201 ±40 min, which was not significantly longer than the half‐life following i.v. administration of the drug. Based on the pharmacokinetic values obtained in this study, a dosing rate of 2.5 mg/kg administered by i.m. injection at 12‐h intervals can be recommended. This dosage regimen should achieve an average steady state serum concentration of 4m̈g/ml with peak serum concentration approaching, but no

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1994.tb00521.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Anadón, A., Bringas, P., Martinez‐Larrañaga, M.R., Diaz, M.J. Bioavailability, pharmacokinetics and residues of chloramphenicol in the chicken. J. vet. Pharmacol Therap.17, 52–58.The pharmacokinetic properties of chloramphenicol were determined in broiler chickens after two sinSle oral doses (30 and 50 mg/kS body weight) and after a single intravenous (i.v.) dose (30 mg/kg body weight). After oral and i.v. administration, the plasma concentration‐time graph was characteristic of a two‐compartment open model. After oral administration (30 and 50 mg/kg). chloramphenicol was absorbed rapidly (time to maximal concentration of 0.72 or 0.60 h) and eliminated with a mean half‐life (t½β) of 6.8 7 or 7.41 h, respectively. The bioavailability was 29% at 30 mg/kg chloramphenicol and 38% at 50 mg/kg chloramphenicol. Concentrations greater than 5 (m̈g/ml were achieved at 15 min and persisted up to 2 or 4 h post‐administration, respectively. Statistically significant differences between the two routes of administration were found for the pharmacokinetic variables, half‐lives of both distribution and elimination phases (t½αt½β) and apparent volume of distribution [Vd(area)]. The meant½β of chloramphenicol and i.v. administration was 5.23 h. Chloramphenicol was extensively metabolized into dehydrochloramphenicol (DH‐CAP), nitrophenylaminopropanedione (NPAP) and nitroso‐chlorampheni‐col (NO‐CAP) derivatives. Residues of chloramphenicol (CAP) and the three metabolites DH‐CAP, NPAP and NO‐CAP in kidney, liver and muscle were measured in chickens that received an oral dose of 50 mg/kg once daily for 4 days. The results indicate that CAP and DH‐CAP residues were cleared slowly and were at or below the detection limit of 0.005m̈g/ml within 12 days after dosing. However, at the time of slaughter (12 days), the NPAP and NO

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1994.tb00522.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY