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1.
The pharmacokinetics of enrofloxacin and its active metabolite ciprofloxacin were investigated in goats after a single intramuscular administration of enrofloxacin at 2.5 mg/kg body weight. The plasma concentrations of enrofloxacin and ciprofloxacin were determined simultaneously by a HPLC method. The peak concentrations (C max) of enrofloxacin (1.13 g/ml) and ciprofloxacin (0.24 g/ml) were observed at 0.8 and 1.2 h, respectively. The elimination half-life (t 1/2), volume of distribution (V d(area)), total body clearance (ClB) and mean residence time (MRT) of enrofloxacin were 0.74 h, 1.42 L/kg, 1329 ml/h per kg and 1.54 h, respectively. The t 1/2, area under the plasma concentration–time curve (AUC) and the MRT of ciprofloxacin were 1.38 h, 0.74 g h/ml and 2.73 h, respectively. The metabolic conversion of enrofloxacin to ciprofloxacin was appreciable (36%) and the sum of the plasma concentrations of enrofloxacin and ciprofloxacin was maintained at or above 0.1 g/ml for up to 4 h. Enrofloxacin appears to be useful for the treatment of goat diseases associated with pathogens sensitive to this drug.  相似文献   

2.
The disposition kinetics and dosage regimen of enrofloxacin were investigated in breeding buffalo bulls following a single intramuscular administration of 5 mg/kg. The absorption half-life, half-life of the terminal phase, apparent volume of distribution and total body clearance were 0.262±0.099 h, 1.97±0.23 h, 0.61±0.13 L/kg and 210.2±18.6 ml/(kg.h), respectively. Therapeutic plasma levels (1 g/ml) were maintained for up to 6 h. A satisfactory intramuscular dosage regimen for enrofloxacin in buffalo bulls would be 8.5 mg/kg followed by 8.0 mg/kg at 8 h intervals.  相似文献   

3.
A pharmacokinetic study of demeclocycline was carried out following intravenous administration at 5 mg/kg body weight in lactating goats. Demeclocycline appeared within 5 min in plasma, interstitial fluid (isf) and urine, while it appeared at 1 h in milk. Peak concentrations of 21.70±4.06, 2.67±0.23, 5.65±0.45 and 82.23±10.06 g/ml were attained at 5 min and at 6, 8 and 8 h in plasma, isf, milk and urine respectively. A potentially therapeutic concentration of 0.5 g/ml was maintained from 5 min–36 h, 30 min–30 h, 1–36 h and 5 min–48 h in plasma, isf, milk and urine respectively. The drug was detectable in all the above biological fluids for at least 48 h. A low distribution half life (t1/2) of 0.44±0.04 h and a high elimination half life (t1/2) of 19.24±1.22 h denote rapid distribution but very slow elimination of the drug in goats. A high tissue plasma concentration ratio [K12:(K2I–)] of 5.12±0.97 during the elimination phase and a Vdarea of 1.59±0.18 L/kg indicate uniform distribution of demeclocycline in the tissues and body fluids of goats. The dosage regimen for maintaining minimum plasma concentration (C min = MIC) of 0.5, 1.0 and 1.5 g/ml at selected dosage intervals of 12 and 24 h was also calculated.  相似文献   

4.
The kinetic profiles of norfloxacin were evaluated in afebrile, febrile and probenecid pre-treated (70 mg/kg orally) febrile goats after a single intravenous (i.v) dose (5 mg/kg). Fever was induced and maintained for 12 h by injecting Escherichia coli endotoxin (0.2 g/kg, i.v.) and repeating it in half the dose (0.1 g/kg) 5 h later. The plasma pharmacokinetic values for norfloxacin were best represented using a two-compartment open model. The peak norfloxacin plasma level of 90.52±3.18 g/ml attained in the probenecid pre-treated febrile goats was higher than that in the febrile (75.46±0.72 g/ml) or afebrile goats (62.25±1.23 g/ml). ClB and K el values were significantly (p<0.01) decreased in febrile compared with afebrile goats. These values were further reduced in febrile goats after probenecid pre-treatment. However, t 1/2 was not affected by the fever-probenecid interaction. Norfloxacin may be used as an infusion with probenecid in caprine diseases where very high plasma levels are required to combat resistant organisms such as Bacteroides.Abbreviations MIC minimum inhibitory concentration - LPS lipopolysaccharide - i.v. intravenous(ly)  相似文献   

5.
The plasma concentrations and pharmacokinetics of the fluoroquinolone antimicrobial agent pefloxacin, following the administration of a single intravenous (10 mg/kg) or oral (20 mg/kg) dose, were investigated in healthy female goats. The antimicrobial activity in plasma was measured at predetermined times after drug administration by an agar well diffusion microbiological assay, using Escherichia coli (ATCC 25922) as the test organism. Concentrations of the drug 0.25 g/ml were maintained in plasma for up to 6 and 10 h after intravenous (IV) or oral administration of pefloxacin, respectively. The concentration–time data for pefloxacin in plasma after IV or oral administration conformed to two- and one-compartment open models, respectively. Plasma pefloxacin concentrations decreased rapidly during the initial phase after IV injection, with a distribution half-life (t 1/2 ) of 0.10±0.01 h. The terminal phase had a half-life (t 1/2 ) of 1.12±0.21 h. The volume of distribution at steady state (V dss), mean residence time (MRT) and total systemic clearance (ClB) of pefloxacin were 1.08±0.09 L/kg, 1.39±0.23 h and 821±88 (ml/h)/kg, respectively. Following oral administration of pefloxacin, the maximum concentration in the plasma (C max) was 2.22±0.48 g/ml and the interval from administration until maximum concentration (t max) was 2.3±0.7 h. The absorption half-life (t 1/2 ka), mean absorption time (MAT) and elimination half-life of pefloxacin were 0.82±0.40, 4.2±1.0 and 2.91±0.50 h, respectively. The oral bioavailability of pefloxacin was 42%±5.8%. On the basis of the pharmacokinetic data, a dosage regimen of 20 mg/kg, IV at 8 h intervals or orally twice daily, is suggested for treating infections caused by drug-sensitive pathogens in goats.  相似文献   

6.
A pharmacokinetic study of doxycycline after intravenous administration at 5 mg/kg body weight in goats revealed that a concentration of 0.5 g/ml was maintained for 5 min-2 h, 4–12 h, 2–12 h and 5 min- >48 h in plasma, interstitial fluid, milk and urine respectively. The low t1/2 of 0.73±0.11 h and high t1/2 of 16.63±1.58 h show that the drug is rapidly distributed but slowly eliminated from the body. The tissue:plasma concentration of 4.86±1.06 during the elimination phase [K12/(K21-)] indicates a high expected tissue concentration, which is supported by similarly increased drug concentration in interstitial fluid and milk. The high Vdarea of 9.78±0.86 L/kg observed denotes that, apart from its wide distribution, the drug may be stored in fat depots as it is known to be highly lipophilic. As the drug maintained a therapeutic concentration for a shorter time in plasma, and the calculated dose rate for maintaining a minimal plasma concentration of 0.5–1.5 g/ml is relatively high, it may not be of much use in treating septicaemia in this species. Since the observed tissue:plasma concentration was higher and a therapeutic concentration was maintained in interstitial fluid and milk for longer, the drug can be used for other systemic infections at a lower dose rate than that required for treating septicaemia. As the drug maintained a very high concentration in urine, it may be of particular value in treating urinary tract infections caused by sensitive micro-organisms.  相似文献   

7.
The aim of this study was to elucidate some of the pharmacokinetic parameters of pefloxacin in lactating goats (n = 5) following intravenous (i.v.) or intramuscular (i.m.) injections of 10 mg/kg bw. Serially obtained serum, milk and urine samples were collected at precise time intervals, and the drug concentrations were assayed using a microbiological assay. A two-compartment open model best described the decrease of pefloxacin concentration in the serum after intravenous administration. The maximum serum concentration (C p 0 ) was 8.4±0.48 g/ml; elimination half-life (t 1/2) was 1.6±0.3 h; total body clearance (Cltot) was 3.6±0.3 L/kg/h; steady-state volume of distribution (V dss) was 5.14±0.21 L/kg; and the area under the curve (AUC) was 2.78±0.22 g.ml/h. Pefloxacin was absorbed rapidly after i.m. injection with an absorption half-life (t 1/2ab) of 0.32±0.02 h. The peak serum concentration (C max) of 0.86±0.08 g/ml was attained at 0.75 h (T max). The absolute bioavailability after i.m. administration was 70.63±1.13% and the serum protein-bound fraction ranged from 7.2% to 14.3%, with an average value of 9.8±1.6%. Penetration of pefloxacin from the blood into the milk was rapid and extensive, and the pefloxacin concentration in milk exceeded that in serum from 1 h after administration. The drug was detected in milk and urine for 10 and 72 h, respectively; no samples were taken after 72 h.  相似文献   

8.
A two-way crossover study was conducted in crossbred male calves (6–8 months old) to determine the bioavailability, pharmacokinetics and dosage regimens for a long-acting formulation of oxytetracycline (OTC-LA). The half-lives of oxytetracycline after intravenous and intramuscular administration were 7.8 h and 24 h, respectively. The volume of distribution and total body clearance values of the drug were 0.86±0.07 L and 76.1±3.3 (ml/h)/kg, respectively. The maximum concentration of the drug in the serum (4.7–7.4 g/ml) was achieved 8–10 h after intramuscular administration. The minimum therapeutic serum concentration of drug of 0.5 g/ml was maintained between 15 min and 84 h after intramuscular administration. The intramuscular bioavailability of the drug was 89.1±4.2%. The dosage regimens to maintain the minimum therapeutic serum concentrations of OTC following intramuscular administration of OTC-LA were computed.  相似文献   

9.
The synthetic androgen 19-nortestosterone (-NT) has been used illegally as a growth promoter in cattle production in the European Union. Elimination of -NT and its metabolites in plasma, urine and bile was studied in three cattle with cannulated gallbladders following intramuscular injection at a single site of 500 mg of the laurate ester (NTL) containing 300.5 mg -NT. Using enzyme immunoassay quantification, plasma Cmax of free -NT was 0.5±0.15 g/L (mean±SEM). Concentrations of free -NT in plasma were consistently greater than the assay limit of quantification (0.12 g/L) for 32.7±13.42 days. Mean residence time for free -NT in plasma was 68.5±20.75 days. Following sample preparation by immunoaffinity chromatography, high-resolution GC-MS was used to quantify -NT and -NT in urine and bile. -NT was detected irregularly in urine from two of the three animals post injection. The principal metabolite present in the urine, -NT, was detected for 160.3±22.67 days post injection. Cmax for -NT in urine was 13.7±5.14 g/L. Mean urinary AUC0–183 days for -NT was 845.7±400.90 (g h)/L.In bile, -NT was the only metabolite detected for 174.3±8.67 days post treatment. Cmax for -NT in bile was 40.8±12.70 g/L and mean biliary AUC0–183 days for -NT was 1982.6±373.81 (g h)/L. Concentrations of -NT in bile samples were greater than those in urine samples taken at the same time. The mean ratio of biliary:urinary AUC0–183 days was 3.0±0.72. It is concluded that bile is a superior fluid for detection of -NT following injection of NTL, owing to the longer period during which residues may be detected after administration.  相似文献   

10.
A pharmacokinetic study of ampicillin (6 mg/kg intravenous) revealed that the peak concentrations of 17.81±1.25, 5.64±2.24 and 1.09±0.10 g/ml of the drug were attained at 15 min, 30 min and 2 h in plasma, milk and uterine fluid respectively. A therapeutic concentration of 0.1 g/ml was maintained from 15 min–8 h, 15 min–6 h and 30 min–6 h in plasma, milk and uterine fluid. Hence, the drug may be used effectively in mammary gland and uterine infections apart from its use in other systemic infections.  相似文献   

11.
The disposition and dosage regimen of cephaloridine were investigated in healthy calves following a single intramuscular administration of 10 mg/kg. The absorption halflife, climination halflife, apparent volume of distribution and total body clearance were 0.107±0.025 h, 2.08±0.14 h, 0.70±0.07L kg-1 and 235.8±21.9 ml kg-1 h-1, respectively. Therapeutic plasma levels (1 g/ml) were maintained for up to 7 h. A satisfactory intramuscular dosage regimen for cephaloridine in calves would be 10 mg/kg repeated at 8 h intervals.  相似文献   

12.
The disposition kinetics and urinary excretion of pefloxacin after a single intravenous administration of 5 mg/kg were investigated in crossbred calves and an appropriate dosage regimen was calculated. At 1 min after injection, the concentration of pefloxacin in the plasma was 18.95±0.892 g/ml, which declined to 0.13±0.02 g/ml at 10 h. The pefloxacin was rapidly distributed from the blood to the tissue compartment as shown by the high values for the initial distribution coefficient, (12.1±1.21 h–1) and the constant for the rate of transfer of drug from the central to the peripheral compartment, K 12 (8.49±0.99 h–1). The elimination half-life and volume of distribution were 2.21±0.111 h and 1.44±0.084 L/kg, respectively. The total body clearance (ClB) and the ratio of the drug present in the peripheral to that in the central compartment (P/C ratio) were 0.454±0.026 L/kg h) and 5.52±0.519, respectively. On the basis of the pharmacokinetic parameters obtained in the present study, an appropriate intravenous dosage regimen for pefloxacin in cattle for most of the bacteria sensitive to it would be 6.4 mg/kg repeated at 12 h intervals.  相似文献   

13.
Ninety-three unhealthy dogs (including some with diabetes mellitus or insulinoma) of different ages, sex and breeds were divided into 10 groups according to their pathology. Serum fructosamine concentrations were determined using a commercial colorimetric nitroblue tetrazolium method. Diabetic dogs had the highest fructosamine concentrations (454.85±149.34 mol/L). Dogs with insulinoma had significantly lower fructosamine concentrations (202.80±31.22 mol/L), similar to those with leishmaniosis (202.83±99.83 mol/L). Fructosamine concentrations in non-healthy dogs, except those with diabetes mellitus, insulinoma or leishmaniosis, were within the reference limits previously reported.  相似文献   

14.
The study elucidated the pharmacokinetics of streptomycin in healthy lactating she-buffaloes after a single intramuscular (IM) injection (10 mg/kg). The drug attained its peak concentrations of 24.39±2.67, 0.45±0.05 and 5.06±0.18 g/ml at 1, 4 and 1 hour in plasma, milk and uterine fluid respectively. Calculations based on the assumption of a 2-compartment model gave a plasma t1/2 () of 4.01±0.44 h and an apparent volume of distribution [Vd(area)] of 0.47±0.06 l/kg. The drug was detectable in the plasma, milk and uterine fluid for 30, 8 and 12 hours, respectively. A therapeutic concentration of the drug was maintained for 6 to 7 hours in the plasma and for around 1 hour only in the uterine fluid. However, a therapeutic level could not be achieved in milk at any time. The results suggest that the drug can be used clinically by the IM route against streptomycin susceptible systemic infections but not those in the uterus and mammary gland.  相似文献   

15.
The hepatic mitochondrial carnitine palmitoyltransferase (CPT) activity was measured by fluorimetric assay in dairy cows with or without fatty liver. CPT activities in 13 lactating cattle and in 6 non-lactating cows were 304.4±86.6 mol CoA/min per g protein and 169.3±84.8 mol CoA/min per g protein, respectively. This difference was significant (<0.05). CPT activities in early lactation (0–110 days after calving), mid-lactation (111–220 days after calving) and late lactation (over 220 days after calving) were 278.9±68.0, 312.4±124.1 and 320±59.3 mol CoA/min per g protein, respectively. There was no significant difference between the values at different stages of lactation. The CPT activity in 10 lactating cows with fatty liver unrelated to calving was 201.3±80.0 mol CoA/min per g protein. CPT activity in 10 cattle with fatty liver was significantly lower than that in normal lactating cattle. Based on these findings, clinical fatty liver unrelated to calving appears to be associated with a decrease in hepatic CPT activity.  相似文献   

16.
The plasma levels, disposition kinetics and a dosage regimen for pralidoxime (2-PAM) were investigated in male buffalo calves following single intramuscular administration (15 or 30 mg/kg). The effects of 2-PAM on various blood enzymes were also determined. The absorption half-life, elimination half-life, apparent volume of distribution and total body clearance of 2-PAM were 1.08±0.19 h, 3.14–3.19 h, 0.83–1.01 L/kg and 184.9–252.1 ml/(kg h), respectively. At doses of 15 and 30 mg/kg body weight, a plasma concentration 4 g/ml was maintained for up to 4 and 6 h, respectively. Pralidoxime significantly lowered the serum level of transferases, phosphatases and lactate dehydrogenase but did not influence the acetylcholinesterase and carboxylesterase enzymes. The most appropriate dosage regimen for 2-PAM in the treatment of organophosphate toxicity in buffaloes would be 25 mg/kg followed by 22 mg/kg at 8 h intervals.  相似文献   

17.
The morphology of the erythrocyte cell series was investigated in external jugular vein blood samples from Dwarf and Danish Landrace goats aged from one day to 12 months. Three erythrocytic cell types were observed in neonates after supravital staining with new methylene blue. The first type were macrocytes which were stained uniformly dark to muddy blue. They formed the majority of the erythrocytic cells at birth and were categorized as diffusely basophilic chromatophilic erythrocytes. The second type were punctate and aggregated reticulocytes, and the type were mature erythrocytes. The size ranges of the three erythrocytic cells were 4.2–5.6, 4.9–6.3 and 2.8–3.5 m diameter respectively in the Dwarf kids and 5.6–9.7, 4.2–9.0 and 3.8–4.2 m respectively in the Landrace kids during the first week of life. Romanowsky-stained blood smears from neonatal kids were characterized by anisocytosis and poikilocytosis in which polychromatophilic macrocytes were numerous, but reticulocytes were not clearly identifiable. The ranges of erythrocyte diameters in Romanowsky-stained neonatal blood films were 4.4–5.8 (5.2±0.39) and 4.1–6.7 (5.1±0.67) m in Dwarf and Landrace kids respectively, decreasing to 3.0±0.15 and 3.3±0.13 m in the two broods respectively by 12 months of age. The numbers of diffusely basophilic polychromatophilic erythrocytes and punctate/aggregated reticulocytes diminished with age and they were not observed in 1–2-month-old kids.  相似文献   

18.
Florfenicol, a monofluorinated analogue of thiamphenicol, has a broad antibacterial spectrum. The pharmacokinetics of florfenicol was studied following a single intravenous (i.v.) or intramuscular (i.m.) injection at a dose of 20 mg/kg body weight in healthy male camels, sheep and goats. The concentration of florfenicol in plasma was determined using a microbiological assay. Pharmacokinetic analysis was performed using a two-compartment open model. Following i.m. administration, the maximum plasma concentration of florfenicol (C max) reached in camels, sheep and goats was 0.84±0.08, 1.04±0.10 and 1.21±0.10 g/ml, respectively, the the time required to reach C max (t max) in the same three respective species was 1.51±0.14, 1.44±0.10 and 1.21±0.10 h. The terminal half-life (t 1/2) and the fraction of the drug absorbed (F%) in camels, sheep and goats were 151.3±16.33, 137.0±12.16 and 127.4±11.0 min, and 69.20%±7.8%, 65.82%±6.7% and 60.88%±5.9%, respectively. The MRT in the same three respective species was 4.01±0.45, 3.42±0.39 and 2.98±0.32 h. Following i.v. administration, the terminal half-life (t 1/2) and total body clearance (ClB) in camels, sheep and goats were 89.5±9.2, 78.8±8.3 and 71.1±8.9 min and 0.33±0.04, 0.30±0.03 and 0.27±0.03 L/h per kg, respectively. The area under the curve (AUC0–) and the mean residence time (MRT) in the same three respective species were 60.61±6.98, 62.45±6.56 and 74.07±7.85 g/ml per h, and 2.71±0.31, 2.34±0.25 and 2.11±0.23 h. These data suggest that sheep and goats absorb and clear florfenicol to a broadly similar extent, but the rate and extent of absorption of the drug tends to be higher in camels. Drug treatment caused no clinically overt adverse effects. Plasma enzyme activities and metabolites indicative of hepatic and renal functions measured 1, 2, 4 and 7 days following the drug treatment were within the normal range, indicating that the drug is safe at the dose used.  相似文献   

19.
The disposition kinetics of fenvalerate were studied in goats after dermal application of 100 ml of 0.25% (w/v) solution. The insecticide persisted in the blood for 72 h. The mean (±SEM) V d(area) and apparent t 1/2 () were 9.92±1.44 L/kg and 17.51±2.65 h, while the AUC and ClB values were respectively 82.15±7.40 g h/ml and 0.56±0.05 L/(kg h). Four days after the dermal application, the highest concentration of fenvalerate residues was found in the adrenal gland, followed by the biceps muscle, omental fat, liver, kidney, lung and cerebrum in that order. Fenvalerate caused hyperglycaemia but had no effect on serum protein and cholesterol levels. Serum acetylcholinesterase activities were increased after 24 h but were below the initial values from 48 to 120 h.Abbreviations Ache acetylcholinestase - AUC total area under the blood insecticide concentration-versus-time curve - ClB total body clearance - GLC gas-liquid chromatography - t 1/2() apparent elimination half-life - V d(area) apparent volume of insecticide distribution based on area method  相似文献   

20.
The purpose of the present investigation was to test the hypothesis that drug-induced changes in rumen contractions influence feed intake in dwarf goats. Intravenous (i.v.) administration of clonidine (1 g kg-1 min-1 for 10 min), xylazine (1 g kg-1 min-1 for 10 min), and PGF-2 (10 g kg-1 min-1 for 15 min) caused bradycardia and inhibition of rumen contractions. However, no appetite-stimulating effect of these drugs was observed. Other clinical changes induced by the 2-adrenergic agonists included slight sedation and a decrease in body temperature; all clinical effects of clonidine and xylazine were partly antagonized by tolazoline pretreatment (10 g kg-1 min-1 for 30 min). These results suggest that the CNS control of feeding differs in ruminants and monogastric species.In dwarf goats fasted for 2 h, i.v. administration of oxytocin (0.01 IU kg-1 min-1 for 15 min), vasopressin (0.01 IU kg-1 min-1 for 15 min), octapressin (0.003 IU kg-1 min-1 for 15 min) or PGE (0.8 g kg-1 min-1 for 15 min) did not change feeding behaviour during the two observation periods (0–30 min and 180–210 min after drug infusion, respectively). In previous studies, similar doses of these drugs induced changes in heart rate and inhibition of rumen contraction in goats. These findings demonstrate that drug-induced changes in forestomach contractions do not simply cause changes in feeding behaviour. The i.v. infusion of the PGF2 analogues etiproston (10 g kg-1 min-1 for 15 min), luprostiol (30 g kg-1 min-1 for 15 min), cloprostenol (1 g kg-1 min-1 for 15 min) and tiaprost (1 g kg-1 min-1 for 15 min) induced hypophagic effects and stimulated intestinal propulsion.  相似文献   

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