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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 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   

3.
The pharmacokinetics of fenbendazole and oxfendazole in cattle are described. The pharmacokinetics of oxfendazole were not significantly different when administered orally and by intra-ruminal injection. At a dose rate of 4.5 mg/kg, administered orally, fenbendazole gave rise to mean peak concentrations in plasma of fenbendazole and oxfendazole of 0.11 and 0.13 g/ml respectively. Oral administration of oxfendazole, at 4.5 mg/kg body weight, gave rise to plasma peak concentrations of fenbendazole and oxfendazole of 0.10 and 0.20 g/ml respectively. Following intra-ruminal administration of oxfendazole, the peak concentrations were 0.11 and 0.18 g/ml respectively.  相似文献   

4.
Strips of rumen wall from bovine fetuses were incubated in an organ bath with acetylcholine only (0.16 to 5.12 g/ml) or in the presence of neostigmine (0.20 g/ml) or atropine (0.05g/ml). The highest reactivity was observed in the period of 4.0–5.9 months of fetal age. This reactivity could be associated with the starting point of rumen papillary development.  相似文献   

5.
Young adult sheep were dosed with extracts of Narthecium ossifragum plants by the oral or parenteral routes and the resulting nephrotoxicity was assessed from the increases in the concentrations of creatinine and urea in the serum. Following single intraruminal or intraperitoneal doses of extracts derived from 30 g N. ossifragum (wet weight) per kg live weight (kg lw), serum creatinine concentrations increased from about 100 mol/L to between 260 and 510 mol/L. The serum urea concentrations increased from about 5–8 mmol/L to between 11 and 66 mmol/L in individual sheep. Daily intraruminal administration of 5–30 g/kg lw to three sheep over a 10- or 15-day period increased creatinine concentrations from 100 mol/L to 300–760 mol/L, and urea concentrations from 5–8 mmol/L to 35 mmol/L. A single intraperitoneal challenge dose of 30 g/kg lw, delivered 7 or 12 days after the final intraruminal dose, did not lead to increased serum creatinine or urea concentrations, indicating that oral treatment had apparently resulted in an increased tolerance to the nephrotoxic principle(s) in N. ossifragum.  相似文献   

6.
The pharmacokinetics of sulphadimidine after a single dose (200 mg/kg i.v.) was studied in five healthy lactating buffaloes. The study revealed that the drug attained its peak concentration of 314.0±13.0, 242.4±3.0 and 100.2±2.5 g/ml at 15 min, 30 min and 12 h in plasma, milk and uterine fluid, respectively. The pharmacokinetic parameters calculated by a 2-compartment open model gave values for t1, t1 and vdarea of 2.10±0.36 h, 12.36±0.57 h and 1.23±0.07 L/Kg, respectively. A high vdarea as well as a value of 0.74±0.08 for K12:K21- (tissue Plasma) indicates better penetration of the drug into the different body fluids and tissues, which is further supported by a high concentration obtained in milk and uterine fluid. The therapeutic concentration (50 g/ml) was maintained for around 24 h in plasma and milk and 12 h in uterine fluid. The results suggest that, apart from its use in systemic infections, the drug can be effectively used by the i.v. route in uterine and mammary gland infections. The dosages for maintaining concentration of 50 g/ml, 100 g/ml and 150 g/ml at convenient dosage intervals of 12 and 24 h were also determined.  相似文献   

7.
The effect of an intravenous bolus injection of endotoxin, 0.1, 1 or 10 g/kg, on rectal temperature, clinical appearance, haematological parameters, and on gastrointestinal electrical activity was examined in 11 conscious piglets of 4–5 weeks of age, with implanted electrodes in the antrum pylori, duodenum, jejunum and ileum. All doses resulted in a significant and dose-dependent increase in rectal temperature, in pronounced clinical signs and in distinct changes in haematological values. These included shivering, depression, respiratory distress, a leukopenia (0.1 g/kg) or a leukocytosis (1 g/kg) with a shift to the left, an accelerated sedimentation rate and a decreased packed cell volume. Doses of 1 and 10 g/kg induced a transient inhibition of gastroduodenal electrical activity. These results suggest that, in the piglet, endotoxin primarily manifests general clinical signs and that the gastrointestinal effects coincide with these.  相似文献   

8.
Strips of smooth muscle from the pulmonary vein, pulmonary artery, trachea and bronchus of calves were incubated in an organ bath with 3-methylindole (3MI) and 3-methyloxindole (3MOI). 3MI and 3MOI (5–640 g/ml) did not cause contraction of any of the isolated smooth muscle preparations. No evidence for the release of mediators of anaphylaxis was obtained when chopped bovine lung preparations were incubated with 3MI (20 g/ml) and 3MOI (25 g/ml). Results of the present work diminish the possibility that the pneumotoxic effect of 3MI is due to a primary hydrodynamic imbalance across the alveolocapillary membrane resulting in excess filtration over reabsorption.  相似文献   

9.
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   

10.
Residues of dimetridazole in eggs after treatment of laying hens   总被引：1，自引：0，他引：1  
Laying hens were dosed orally with dimetridazole (DMZ) (50 and 250 mg/kg) for 3 days or intramuscularly (50 mg/kg), also for 3 days, and the residues were determined by liquid chromatography in albumen and yolk. The sensitivity of the whole procedure was 2 ng/g. The drug was excreted preferentially into the yolk (about 57% of the total) and the elimination period lasted for 4–6 days after treatment.Abbreviations AUC area under the plasma concentration-time curve - depletion time the time needed for the DMZ concentration to fall below 0.01 g/g - elimination rate constant - Cl clearance - DMZ demetridazole  相似文献   

11.
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   

12.
The effects of opioids and naloxone on cyclical forestomach motility were determined in anaesthetized and conscious sheep. To assess central or peripheral opioid actions, differential routes of administration were used. Possible dynamic effects along the innervating vagovagal reflex arc were investigated electrophysiologically at the cervical level of the vagus nerve. Further, direct influences on the smooth muscle were evaluatedin vitro on isolated longitudinal reticular strips. Additionally, the effects of some spasmogenic agents were studied for comparative purposes. In anaesthetized sheep, opioids depressed in an identical manner both the amplitude of spontaneous cyclical contractions and contractions evoked by electrical stimulation of the distal end of the cut cervical vagus. In conscious sheep, low doses of normorphine and loperamide inhibited frequency and amplitude centrally (20 g/kg and 4 g/kg via carotid artery respectively), whereas locally higher dose levels (200 g/kg and 10 g/kg via coeliac artery respectively) affected only the amplitude of cyclical contractions. Furthermore the opioid peptides Leu-, Met-enkephalin and [D-Ala2-Met5]-enkephalinamide preferentially depressed the amplitude of cyclical motility most efficiently if administrated via the coeliac artery. These results indicate the presence both of a central opioid action depressing frequency and amplitude and of a local opioid action depressing only the amplitude of cyclical reticulo-ruminal motility. Opioids did not alter the resting discharge of afferent tension units and similarly failed to modulate tone of reticular stripsin vitro, suggesting that the opioids act locally on the intramural neuronal plexus, possibly by diminishing the output of excitatory transmitter. Whether substance P could play a role as a vagal excitatory transmitter besides the classically implicated acetylcholine has been discussed. The central opioid mechanism is probably not situated within the gastric centres but elsewhere in the brain. Naloxone ( 100 g/kg, jugular vein) stimulated the frequency of cyclical ruminal motility only in well-defined experimental conditions, probably via a central mechanism.  相似文献   

13.
LPSS. typhimurium (0.3 g per kg) injected intravenously into conscious goats induced an inhibition of the extrinsic ruminal contractions in association with pyrexia and changes in heart rate. Pretreatment with polymyxin B (3 mg per kg i.v.) antagonized the endotoxin-induced symptoms in this species. In rabbits, the intravenous administration of LPSE. coli (0.1 g per kg) resulted in a febrile response, which could be markedly reduced by pretreatment with polymyxin B. Unlike endotoxins, the febrile response to leucocytic pyrogen was not inhibited after pretreatment with this antibiotic. Moreover, polymyxin B caused only a minimal decline in the febrile response due to sodium nucleinate from yeast (10 mg per kg). These results strengthen the view that the antipyretic activity of polymyxin B is due to an interaction of this cationic macromolecule with the anionic endotoxin molecule.  相似文献   

14.
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   

15.
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   

16.
Strips of rumen wall from bovine fetuses were incubated in an organ bath with prostaglandin F2 alpha (0.13 to 33.76 g/ml). The highest reactivity with a submaximal dose (17.03 g/ml) was observed in the period between 3.0 and 7.9 months of fetal age. A smaller response, but higher than in 1.0 to 2.9 months old fetuses, was observed in the 8.0 to 8.9 months fetuses. The period of the highest reactivity to prostaglandin F2 alpha coincides with the age of onset of papillary morphogenesis and the period of highest reactivity to autonomic and putative transmitter drugs.  相似文献   

17.
The disposition kinetics, urinary excretion and a dosage regimen for ciprofloxacin after a single intravenous administration of 5 mg/kg was investigated in 5 healthy buffalo calves. The disposition kinetics were best fitted to a three-compartment open model. After 1 min, the concentration of ciprofloxacin in plasma was 8.50±0.39 g/ml and the minimum therapeutic concentration was maintained for 10 h. The elimination half-life and volume of distribution were 3.88 and 0.08 h and 3.97±0.22 L/kg, respectively. The total body clearance and T/P ratio were 0.709±0.025 L/kg per h and 6.13±0.54, respectively. Approximately 28.3% of the total administered dose of ciprofloxacin was recovered in urine within 24 h of administration. To maintain a minimum therapeutic plasma concentration of 0.10 g/ml, a satisfactory intravenous dosage regimen of ciprofloxacin, computed on the basis of disposition kinetic data obtained in healthy buffalo calves, would be 3 mg/kg repeated at 12 h intervals.  相似文献   

18.
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   

19.
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   

20.
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   

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