摘要:

The pharmacokinetic behaviour of amoxycillin sodium and amoxycillin trihydrate‐20% aqueous suspension was studied in a group of five dairy cows. Amoxycillin sodium was administered intravenously and amoxycillin trihydrate‐20% by four different routes of administration: subcutaneously in the dewlap, intramuscularly in the lateral neck,M. triceps, and buttock (M. semitendineus). The dose level for both drug formulations was 3.83 ± 0.47 mg/kg.The mean plasma concentration–time curve(Cp)for intravenous amoxycillin sodium administration could be described mathematically by the biexponential equationCp= 15.6 e‐0.033t+ 1.04 e‐0.0091t. The areas under the plasma concentration–time curve (AUC's) obtained after the intravenous injections of sodium amoxycillin were used as references for the bioavailability studies of the four routes of amoxycillin trihydrate administration.Intramuscular injections into the lateral neck or into theM. tricepsresulted in similar systemic bioavailabilities, being at 12 h post injection (p.i.) 76.2 and 79.2% of the administered dose. The biological half‐lives (t1/2) were similar, being 6.2 and 6.9 h, respectively. After subcutaneous injection into the dewlap or intramuscular injection into the buttock lower bioavailabilities at 12 h p.i. were observed (24.1 and 49.2%, respectively). The plasma amoxycillin concentration was persistently low. The half‐lives of plasma amoxycillin disposition after the buttock and dewlap injections were 13.2 and 44 h, respectively.The plasma concentrations obtained were compared with minimal inhibitory concentrations (MIC) against pathogenic bacteria with respect to the theoretical design of effective antibacterial therapy. The differences observed serve to emphasize the fact that more attention should be paid to the effect of the route of administration on the biological bioavailability of a drug, with particular reference to studies on clinical efficacy. Pre‐slaughter withdrawal times were suggested for the different routes of injection of these t

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1980.tb00417.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Each of two male and two female healthy, non‐fasted mongrel dogs weighing approximately 13.6 kg were given subcutaneous injections of clindamycin‐2‐phosphate sterile solution. The doses were 2.75, 5.51, 11.02 and 21.04 mg clindamycin free base as clindamycin‐2‐phosphate/kg of body weight. Serum samples were assayed for clindamycin bioactivity as a function of time and the pharmacokinetics determined. The elimination curves were biexponential with mean values for α of 0.466‐1and 0.0498 h‐1for β. The three lower doses demonstrated linear pharmacokinetics (constant total body clearance) while the highest dose did not. Based on the pharmacokinetics, a dosage regimen of 11.02 mg of clindamycin free base as clindamycin‐2‐phosphate/kg of body weight every

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1980.tb00418.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Five adult domestic cats were each given three separate 3‐day courses of chloramphenicol, using a different oral‐dosage regimen each time. The regimens were: 120 mg/kg/day divided 8‐hourly, 60 mg/kg/day divided 8‐hourly, and 50 mg per cat every 12 h (25–40 mg/kg/day). The interval between successive courses was 3 weeks. On the third day of each course plasma samples were obtained at fixed intervals after dosing and were assayed chemically for chloramphenicol. The ranges from peak to trough chloramphenicol concentrations with each regimen were (values are means ± SEM): 63.8 ± 4.60 to 43.0 ± 3.32 μg/ml (120 mg/kg/day), 42.0 ± 3.63 to 24.7 ± 1.83 μg/ml (60 mg/kg/day), and 24.3 ± 1.72 to 7.5 ± 0.85 μg/ml (50 mg per cat 12‐hourly). Because of these findings, previous toxicity studies, and the proposed therapeutic (effective and safe) concentration for chloramphenicol of 5–15 μg/ml, it is suggested that a regimen of 50 mg per animal every 12 h could be adequate for chloramphenicol therapy in cats of average size (2.5‐3.9 kg) and shou

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1980.tb00419.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Eleven buffalo calves (Bubalus bubalis) of 1‐1 1/2 years of age and weighing between 64 and 174 kg were given chloramphenicol at the dose rates of 10 and 20 mg/kg body weight. Pharmacokinetic parameters were determined from the plasma levels. The median elimination half‐life was estimated to be 2.95 h and the median volumes of distribution were 1.1667 litres/kg with the 10 mg/kg dose and 0.9699 litres/kg with the 20 mg/kg dose. The median metabolic clearance rates were 288.30 and 234.13 ml/h/kg, respectively. From the average plasma concentrations obtained with the 20 mg/kg i.v. dose, it was considered necessary to repeat the drug by the i.m. route with the same dose (four calves) which resulted in prolonging the therapeutic concentration (>5 μg/ml) until 18 h. At therapeutic concentrations, about 60% of the drug was bound to plasma proteins. Using the overall elimination rate constant (0.2354 h‐1) and the apparent specific volume of distribution (0.97 litres/kg), different dosage regimens were calculated so as to obtain plasma concentrations (Cpmin) of 2, 5 and 10

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1980.tb00420.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

The plasma levels of chloramphenicol were determined following i.m. administration in three groups of water buffalo (n= 4 per group). The absorption of chloramphenicol was relatively rapid since concentrations of 7.00 ± 0.62 μg/ml were detected in plasma after 1 h and peak concentrations of 9.25 ± 0.53 μg/ml were obtained 3 h following administration of 30 mg/kg. A concentration of at least 5 μg/ml was achieved at the end of 1 h and persisted up to 12 h (6.79 ± 1.19 μg/ml). With repetition of 10 and 20 mg/kg dose at 12 h, concentrations greater than 5 μg/ml persisted for an additional 8 and 12 h, respectively. The distribution studies of chloramphenicol in tissues and body fluids at 4 h post‐injection (30 mg/kg i.m.,n= 4, group IV), revealed that the highest concentration was seen in bile (31.67 ± 6.21 μg/ml), followed by liver, kidney, plasma, heart, skeletal muscle and brain (4.00

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1980.tb00421.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

The pharmacokinetic behavior of chloramphenicol in Chinese spot‐billed ducks (Anas poecilorhyncha) was investigated. Single doses of chloramphenicol were given by the intravenous (22 mg/kg), intramuscular (22 mg/kg), and oral route (55 mg/kg) to six, seven and six ducks, respectively. Serum samples were collected at various times and analyzed for chloramphenicol by a radio‐enzymatic procedure. The time—concentration curves after intravenous administration were described by one‐compartment kinetics. The mean half‐lives for the intravenous, intramuscular, and oral route were 102.5, 104.5 and 151.4 min, respectively. There was little individual variation in the time—concentration plots for either the intravenous or intramuscular route. However, following oral administration, there was considerable individual variation indicating erratic absorption. From the intravenously derived, pharmacokinetic parameters, dosage regimens applicable to either the intravenous or intramuscular route, wer

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1980.tb00422.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Lithium was administered to adult sheep to estimate its pharmacokinetic parameters and a suitable dosage for chronic psychopharmacological experiments. The triexponential decline of plasma lithium levels was tentatively interpreted with a three‐compartment, open‐model of distribution. Sheep differed from other species by the following features: high faecal excretion of lithium, recycling of lithium through the salivary secretion and low absorption rate of the orally‐administered drug. A chronic oral administration of 1 mmol/kg once daily provided minimal plasma levels of about 1 mmol/l, without toxic side‐effects. The results are discussed with respect to comparative pharmacokinetics of lithium and its potential use in the treatment of behavioral disorders of farm

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1980.tb00423.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

A highly specific antibody has been raised in sheep to an antigen prepared by coupling zeranol hemisuccinate to bovine serum albumin. An assay procedure is described and has been used to measure the cross‐reactivity of the antiserum, and evaluate the sensitivity of the assay method. The only compounds which reacted with the antibody were zeranol 100%, zearalanone 100%, zearalenone 19% and zearalenol 19%. The sensitivity of the assay procedure allows the determination of zeranol and/or its main metabolite zearalanone between 100 and 1000 p

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1980.tb00424.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1980.tb00425.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY