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1.
The pharmacokinetic parameters of phenylbutazone were determined in 18 elephants (Loxodonta africana and Elephas maximus) after single-dose oral administration of 2, 3, and 4 mg/kg phenylbutazone, as well as multiple-dose administrations with a 4-wk washout period between trials. After administration of 2 mg/kg phenylbutazone, mean serum concentrations peaked in approximately 7.5 hr at 4.3 +/- 2.02 microg/ml and 9.7 hr at 7.1 +/- 2.36 microg/ml for African and Asian elephants, respectively, while 3 mg/kg dosages resulted in peak serum concentrations of 7.2 +/- 4.06 microg/ml in 8.4 hr and 12.1 +/- 3.13 microg/ml in 14 hr. The harmonic mean half-life was long, ranging between 13 and 15 hr and 39 and 45 hr for African and Asian elephants, respectively. There was evidence of enterohepatic cycling of phenylbutazone in Asian elephants. Significant differences (P < 0.0001) in pharmacokinetic values occurred between African and Asian elephants for clearance (27.9 and 7.6 ml/hr/kg, respectively), terminal half-life (15.0 and 38.7 hr, respectively), and mean residence time (22.5 and 55.5 hr, respectively) using 2-mg/kg dosages as an example. This suggests that different treatment regimens for Asian and African elephants should be used. There were no apparent gender differences in these parameters for either elephant species.  相似文献   

2.
The objective of this study was to determine the pharmacokinetics of a long-acting formulation of ceftiofur crystalline-free acid (CCFA) following intramuscular injection in ball pythons (Python regius). Six adult ball pythons received an injection of CCFA (15 mg/kg) in the epaxial muscles. Blood samples were collected by cardiocentesis immediately prior to and at 0.5, 1, 2, 4, 8, 12, 18, 24, 48, 72, 96, 144, 192, 240, 288, 384, 480, 576, 720, and 864 hr after CCFA administration. Plasma ceftiofur concentrations were determined by high-performance liquid chromatography. A noncompartmental pharmacokinetic analysis was applied to the data. Maximum plasma concentration (Cmax) was 7.096 +/- 1.95 microg/ml and occurred at (Tmax) 2.17 +/- 0.98 hr. The area under the curve (0 to infinity) for ceftiofur was 74.59 +/- 13.05 microg x h/ml and the elimination half-life associated with the terminal slope of the concentration-time curve was 64.31 +/- 14.2 hr. Mean residence time (0 to infinity) was 46.85 +/- 13.53 hr. CCFA at 15 mg/kg was well tolerated in all the pythons. Minimum inhibitory concentration (MIC) data for bacterial isolates from snakes are not well established. For MIC values of < or =0.1 microg/ml, a single dose of CCFA (15 mg/kg) provides adequate plasma concentrations for at least 5 days in the ball python. For MICs > or =0.5 microg/ml, more frequent dosing or a higher dosage may be required.  相似文献   

3.
Superficial and systemic mycotic infections are common among clinically ill sea turtles, which places growing importance on the establishment of pharmacokinetic-based dosage regimens for antifungal drugs. The pharmacokinetic properties of the antifungal drug fluconazole, after intravenous (i.v.) and subcutaneous (s.c.) injections, were studied in juvenile loggerhead sea turtles (Caretta caretta) housed at 23.0-26.5 degrees C. Fluconazole pharmacokinetic properties were further assessed in a multiple-dose s.c. regimen derived from the pharmacokinetic parameters determined in the single-dose study. Pharmacokinetic parameters were calculated, using a two-compartment model, from plasma concentration-time data obtained after single i.v. and s.c. administrations of fluconazole at a dosage of 2.5 mg/ kg body weight in six juvenile sea turtles. Blood samples were collected at intervals through 120 hr after each dose, and the concentration of fluconazole in plasma was measured by reverse-phase high-performance liquid chromatography. The i.v. and s.c. elimination half-lives were 139.5 +/- 36.0 and 132.6 +/- 48.7 hr (mean +/- SD), respectively. Systemic clearance of fluconazole was 8.2 +/- 4.3 ml/kg x hr, and the apparent volume of distribution at steady state was 1.38 +/- 0.29 L/kg. A multiple-dose regimen was derived, which consisted of a loading dose of 21 mg/kg body weight and subsequent doses of 10 mg/kg administered through s.c. injection every 120 hr (5 days). This regimen was administered to four juvenile sea turtles for 10 days, and blood samples were taken to determine peak and trough plasma concentrations of fluconazole. The mean concentrations for the two peak concentrations were 16.9 +/- 1.1 and 19.1 +/- 2.8 microg/ml 4 hr after dosing, and the mean concentrations for the three trough concentrations were 7.2 +/- 2.2, 10.4 +/- 2.7, and 10.7 +/- 2.9 microg/ml 120 hr after dosing. The terminal half-life after the last dose was calculated at 143 hr. Throughout the multiple dosing, fluconazole concentrations remained above approximately 8 microg/ml, a concentration targeted when treating mycotic infections in humans. The results of this study suggest that fluconazole can be effectively administered to sea turtles at a dosage of 10 mg/kg every 5 days after a loading dose of 21 mg/kg.  相似文献   

4.
Serum oxytetracycline pharmacokinetics were studied in 18 African elephant (Loxodonta africana) calves. Each elephant received separate injections of oxytetracycline at approximately 18 mg/kg i.m. and 8 mg/kg i.v. in a cross-over study. Blood samples were drawn at 0, 24, 48, 72, and 96 hr postinjection. An additional sample was drawn 110 hr before the animals were reinjected in the cross-over study and a final blood sample was drawn 48 hr after the second dose. No lameness or stiffness was observed following i.m. injections. Serum oxytetracycline concentrations >0.5 microg/ml were present 48 hr after initial dosing for all elephants (i.m., i.v., high or low dosage). Only elephants given the high i.m. dosage (18 mg/kg) maintained levels >0.5 microg/ml 72 hr postinjection. No significant difference in serum oxytetracycline concentration with time was observed between the groups given different i.v. dosages. These studies demonstrated that quantifiable serum oxytetracycline concentrations can be maintained in young African elephants with a low-dosage multidose i.m. regimen.  相似文献   

5.
The pharmacokinetics of sarafloxacin applied by oral gavage at a dose of 15 mg/kg b.w. was studied in eel (Anguilla anguilla) at water temperature of 24 degrees C. Sarafloxacin levels were determined using high performance liquid chromatography with a quantitation limit of 0.07 microg/ml or gram. The time to peak plasma concentration, Tmax, was 12 hr and peak concentration, Cmax, was 2.64 microg/ml. The absorption rate constant (k(a)) was 0.23 hr(-1) (r=0.996). The drug disposition curve after Tmax was fitted to a two-compartment open model. The distribution rate constant (alpha) was 0.085 hr(-1) (r=0.972), and the half-life (t(1,2alpha)) was 8.15 hr. The elimination rate constant (beta) was 0.023 hr(-1) (r=0.909), and the half-life (t(1/2beta)) was 30.13 hr. The estimated area under the curve, AUC, was 56.7 microg.hr/ml. The peak concentrations of drug in liver, kidney, muscle, and skin were 13.39 (12 hr), 5.53 (12 hr), 1.82 (24 hr), and 0.78 microg/g (40 hr), respectively. The time for sarafloxacin mean levels to fall below detectable limits in the plasma, muscle, and skin were 7 days but for the liver and kidney were 14 days.  相似文献   

6.
The pharmacokinetics of a single dose of enrofloxacin administered orally, both pilled and in fish, and i.v. to African penguins (Spheniscus demersus) at 15 mg/kg were determined. Plasma concentrations of enrofloxacin and its metabolite ciprofloxacin were measured via high-pressure liquid chromatography with mass spectrometry. An i.v. administration of enrofloxacin resulted in an extrapolated mean plasma concentration of 7.86 microg/ml at time zero. Plasma volume of distribution for i.v. administration was 3.00 L/kg, with a mean elimination half-life of 13.67 hr and a mean total body clearance rate of 3.03 ml/min/kg. Oral administration of enrofloxacin achieved a mean maximum plasma concentration of4.38 microg/ml at 4.8 hr after administration when pilled, whereas mean maximum plasma concentration was 4.77 microg/ml at 1.59 hr after administration when given in fish. Mean terminal elimination half-life was 13.79 hr pilled and 11.93 hr when given in fish. Low concentrations of ciprofloxacin were detected after both oral and i.v. enrofloxacin administration. Enrofloxacin administered to African penguins at 15 mg/kg p.o.q. 24 hr, whether in fish or pilled, is expected to achieve the surrogate markers of efficacy for bacteria with a minimum inhibitory concentration of 0.5 microg/ml or less; however, clinical studies are needed to determine efficacy.  相似文献   

7.
Clarithromycin offers numerous advantages over erythromycin and thus, is an attractive alternative for the treatment of Rhodococcus equi infections in foals. The disposition of clarithromycin was investigated in 6 foals after intragastric administration at a dose of 10 mg/kg body weight. Detectable serum concentrations of clarithromycin were found in 3 of 6 foals at 10 minutes and in all foals by 20 minutes post-administration. Time to peak serum concentration (Tmax) was 1.5 hours and peak serum concentration (Cmax) was 0.92+/-0.17 microg/ml. Mean serum concentrations decreased to 0.03 microg/ml at 24 h. No adverse reactions were noted during or after IG administration in any of the foals. Based on the pharmacokinetic parameters, the MIC90 of R. equi isolates, and predicted steady state concentrations, an oral dose of 7.5 mg/kg given every 12 hours would appear appropriate for the treatment of R. equi infections in foals.  相似文献   

8.
Plasma concentrations and pharmacokinetics of enrofloxacin were determined in 12 loggerhead sea turtles (Caretta caretta) after oral administration. Six turtles in group 1 and group 2 received enrofloxacin at 10 mg/kg and 20 mg/kg of body weight, respectively. Blood was collected from the cervical sinus before administration and at timed intervals up to 168 hr following administration. Plasma concentrations of enrofloxacin were determined using a microbiologic assay. The mean peak plasma concentration (Cmax) was 4.07 microg/ml and 21.30 microg/ml for groups 1 and 2, respectively. Plasma levels were detectable at 168 hr postadministration, with mean values of 0.380 microg/ml for group I and 2.769 microg/ml for group 2. The mean elimination half-life for enrofloxacin was 37.80 hr for group I and 54.42 hr for group 2. These findings indicated that enrofloxacin is absorbed following oral administration in loggerhead sea turtles, and blood levels are maintained up to 168 hr following administration.  相似文献   

9.
The pharmacokinetics of enrofloxacin administered orally and i.v. to American alligators (Alligator mississippiensis) at 5 mg/kg was determined. Plasma levels of enrofloxacin and its metabolite ciprofloxacin were measured using high-performance liquid chromatography and the resulting concentration versus time curve analyzed using compartmental modeling techniques for the i.v. data and noncompartmental modeling techniques for the oral data. A two-compartment model best represented the i.v. data. Intravenous administration of enrofloxacin resulted in an extrapolated mean plasma concentration of 4.19 +/- 4.23 microg/ml at time zero, with average plasma drug levels remaining above 1.0 microg/ml for an average of 36 hr. Plasma volume of distribution for i.v. enrofloxacin was 1.88 +/- 0.96 L/kg, with a harmonic mean elimination half-life of 21.05 hr and mean total body clearance rate of 0.047 +/- 0.021 L/hr/kg. Plasma levels of p.o. enrofloxacin remained below 1.0 microg/ml in all test animals, and average concentrations ranged from 0.08 to 0.50 microg/ml throughout the sampling period. Oral administration of enrofloxacin achieved a mean maximum plasma concentration of 0.50 +/- 0.27 microg/ml at 55 +/- 29 hr after administration, with a harmonic mean terminal elimination half-life of 77.73 hr. Minimal levels of ciprofloxacin were detected after both oral and i.v. enrofloxacin administration, with concentrations below minimum inhibitory concentrations for most susceptible organisms. On the basis of the results of this study, enrofloxacin administered to American alligators at 5 mg/kg i.v. q 36 hr is expected to maintain plasma concentrations that approximate the minimum inhibitory concentration for susceptible organisms (0.5 microg/ml). Enrofloxacin administered to American alligators at 5 mg/kg p.o. is not expected to achieve minimum inhibitory values for susceptible organisms.  相似文献   

10.
The pharmacokinetic parameters of S(+) and R(-) ibuprofen were determined in 20 elephants after oral administration of preliminary 4-, 5-, and 6-mg/kg doses of racemic ibuprofen. Following administration of 4 mg/kg ibuprofen, serum concentrations of ibuprofen peaked at 5 hr at 3.9 +/- 2.07 microg/ml R(-) and 10.65 +/- 5.64 microg/ml S(+) (mean +/- SD) in African elephants (Loxodonta africana) and at 3 hr at 5.14 +/- 1.39 microg/ml R(-) and 13.77 +/- 3.75 microg/ml S(+) in Asian elephants (Elephas maximus), respectively. Six-milligram/kilogram dosages resulted in peak serum concentrations of 5.91 +/- 2.17 microg/ml R(-) and 14.82 +/- 9.71 microg/ml S(+) in African elephants, and 5.72 +/- 1.60 microg/ml R(-) and 18.32 +/- 10.35 microg/ml S(+) in Asian elephants. Ibuprofen was eliminated with first-order kinetics characteristic of a single-compartment model with a half-life of 2.2-2.4 hr R(-) and 4.5-5.1 hr S(+) in African elephants and 2.4-2.9 hr R(-) and 5.9-7.7 hr S(+) in Asian elephants. Serum concentrations of R(-) ibuprofen were undetectable at 24 hr, whereas S(+) ibuprofen decreased to below 5 microg/ml 24 hr postadministration in all elephants. The volume of distribution was estimated to be between 322 and 356 ml/kg R(-) and 133 and 173 ml/kg S(+) in Asian elephants and 360-431 ml/kg R(-) and 179-207 ml/kg S(+) in African elephants. Steady-state serum concentrations of ibuprofen ranged from 2.2 to 10.5 microg/ml R(-) and 5.5 to 32.0 microg/ml S(+) (mean: 5.17 +/- 0.7 R(-) and 13.95 +/- 0.9 S(+) microg/ml in African elephants and 5.0 +/- 1.09 microg/ml R(-) and 14.1 +/- 2.8 microg/ml S(+) in Asian elephants). Racemic ibuprofen administered at 6 mg/kg/12 hr for Asian elephants and at 7 mg/kg/12 hr for African elephants results in therapeutic serum concentrations of this antiinflammatory agent.  相似文献   

11.
Single-dose pharmacokinetics of sulfadimethoxine were determined in six adult camels (Camelus dromedarius) following administration of a mean dosage of 17.5 +/- 2.7 mg/kg both i.v. and p.o. Serial blood samples were collected through an indwelling jugular catheter intermittently for 5 days for both routes. Sulfadimethoxine was assayed using high-performance liquid chromatography. Serum drug concentration versus time data for each animal was subjected to linear regression, with the best-fit model selected based on residual analysis. The data fit best into a two-compartment open model, with first-order input for oral administration. For orally administered drug, mean maximum serum concentration of 19.3 +/- 1.7 microg/ml was reached at 11.41 +/- 2.59 hr, with an elimination rate constant of 0.09/hr +/- 0.05/hr and an elimination half-life of 11.7 +/- 3 hr. Mean peak serum concentration following i.v. administration was 223 +/- 48 microg/ml. Mean volume of distribution at steady state was 0.393 +/- 0.049 L/kg. Elimination rate constants differed with i.v. and oral administration, suggesting a flip-flop model. Oral bioavailability was 103% +/- 38%. Comparison of maximum serum concentrations to the microbial breakpoint concentration reported for sulfadimethoxine (512 microg/ml) suggests that the dose used in this study, 17.5 +/- 2.7 mg/kg, is insufficient for achieving therapeutic serum levels.  相似文献   

12.
Pharmacokinetics of tinidazole in dogs and cats   总被引：1，自引：0，他引：1  
Pharmacokinetics of tinidazole in dogs and cats after single intravenous (15 mg/kg) and oral doses (15 mg/kg or 30 mg/kg) were studied in a randomized crossover study. Tinidazole was completely absorbed at both oral dose levels in cats and dogs. Peak tinidazole concentration in plasma was 17.8 micrograms/ml in dogs and 22.5 micrograms/ml in cats after 15 mg/kg p.o. The oral dose of 30 mg/kg resulted in peak levels of 37.9 micrograms/ml in dogs and 33.6 micrograms/ml in cats. The apparent total plasma clearance of the drug was about twofold higher in dogs than in cats, resulting in an elimination half-life that was twice as long in cats (8.4 h) as in dogs (4.4 h). The apparent volume of distribution was 663 ml/kg in dogs and 536 ml/kg in cats. Therapeutic plasma drug concentrations higher than the MIC values of most tinidazole-sensitive bacteria were achieved for 24 h in cats and for 12 h in dogs after a single oral dose of 15 mg/kg. From the pharmacokinetic standpoint tinidazole seems to be well-suited to clinical use in small animal practice.  相似文献   

13.
Three captive loggerhead sea turtles, Caretta caretta, were used in four trials, one i.v. and three i.m., to determine the pharmacokinetic properties of a single dose of ticarcillin. For the i.v. study, each turtle received a single 50 mg/kg dose and blood samples were collected at 0, 0.5, 1, 2, 4, 6, 8, and 12 hr and at 1, 1.5, 2, 2.5, 3, 4, 6, 8, 10, and 14 days after administration. For the i.m. study, each turtle received one of three dosages (25, 50, or 100 mg/kg) in a randomized complete block design and blood samples were collected at the same time intervals. Each trial was separated by a minimum of 28 days to allow for complete drug clearance. Drug concentration in plasma was determined by a validated liquid chromatography-mass spectrometry assay. For the i.v. study, the elimination half-life was 5.0 hr. The apparent volume of distribution and plasma clearance were 0.17 L/kg and 0.0218 L/hr/kg, respectively. For the i.m. study, mean time to maximum plasma concentrations ranged from 1.7 ( +/- 0.58) hr in the 50 mg/kg group to 3.7 (+/- 2.5) hr in the 100 mg/kg group. Mean bioavailability ranged from 45% ( +/- 15%) in the 50 mg/kg group to 58% (+/- 12%) in the 100 mg/kg group, and the mean residence time ranged from 7.5 ( +/- 2.6) hr in the 25 mg/kg group to 16 (+/- 6.8) hr in the 100 mg/kg group. Two turtles had slight alanine aminotransferase elevations that were not clinically apparent at two different dosages, but otherwise, blood chemistries were unaffected. Possible i.m. dosage regimens for loggerhead sea turtles are 50 mg/kg q24 hr or 100 mg/kg q48 hr. Liver enzymes should be monitored during treatment.  相似文献   

14.
The pharmacokinetics of a long-acting oxytetracycline preparation administered i.v. and i.m. to American alligators (Alligator mississippiensis) at 10 mg/kg was determined. Plasma levels of oxytetracycline were measured using high-performance liquid chromatography, and the resulting concentration versus time curve was analyzed using compartmental modeling and noncompartmental modeling techniques for i.v. and i.m. samples, respectively. A two-compartment model best represented the i.v. data. Intravenous administration of oxytetracycline resulted in an extrapolated mean plasma concentration at time zero of 60.63 +/- 28.26 microg/ml, with average plasma drug levels of 2.82 +/- 0.71 microg/ml at the end of the 192-hr sampling period. Plasma volume of distribution for i.v. oxytetracycline was 0.20 +/- 0.09 L/kg, with a harmonic mean elimination half-life of 15.15 hr and mean total body clearance rate of 0.007 +/- 0.002 L/hr/kg. Intramuscular administration of oxytetracycline achieved a mean peak plasma concentration of 6.85 +/- 1.96 microg/ml at 1 hr after administration, with average plasma drug levels of 4.96 +/- 1.97 microg/ml at the end of the 192-hr sampling period. The harmonic mean terminal elimination half-life for i.m. oxytetracycline was 131.23 hr. Based on the results of this study, long-acting preparations of oxytetracycline administered parenterally to American alligators at 10 mg/kg q 5 days is expected to maintain plasma concentrations above the minimum inhibitory concentration of 4.0 microg/ml for susceptible organisms.  相似文献   

15.
The pharmacokinetics of theophylline were determined in 6 healthy horses after a single IV administration of 12 mg of aminophylline/kg of body weight (equivalent to 9.44 mg of theophylline/kg). Serum theophylline was measured after the IV dose at 0.25, 0.5, 1, 2, 4, 6, 8, 12, and 15 hours. Serum concentration plotted against time on semilogarithmic coordinates, indicated that theophylline in 5 horses was best described by a 2-compartment open model and in 1 horse by a 1-compartment open model. The following mean pharmacokinetic values were determined; elimination half-life = 11.9 hours, distribution half-life = 0.495 hours, apparent specific volume of distribution = 0.885 +/- 0.075 L/kg, apparent specific volume of central compartment = 0.080 L/kg, and clearance = 51.7 +/- 11.2 ml/kg/hr. Three horses with reversible chronic obstructive pulmonary disease were serially given 1, 3, 6, 9, 12, and 15 mg of aminophylline/kg in single IV doses (equivalent to 0.8, 2.4, 4.7, 7.1, 9.44, and 11.8 mg of theophylline/kg, respectively). The horses were exposed to a dusty barn until they developed clinical signs of respiratory distress and were then given the aminophylline. Effects of increasing doses on different days were correlated with clinical signs, blood pH, and blood gases. The 3 horses had a decrease in the severity of clinical signs after the 9, 12, or 15 mg doses of aminophylline/kg. The horses at 0.5 hour after dosing had a significant decrease in PaCO2 (43.6 +/- 5.5 to 39.4 +/- 6.7 mm of Hg, P less than 0.001) and a significant increase in blood pH (7.38 +/- 0.017 to 7.41 +/- 0.023, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

16.
The plasma and salivary disposition of closantel and rafoxanide were examined following intravenous administration in adult sheep. Two studies were conducted with rafoxanide at 7.5 mg/kg and 1 with closantel using 2 doses (5 and 15 mg/kg). The pharmacokinetic profile of both drugs in plasma were best described by a 2-compartmental model with 1st-order rate constants. Plasma disposition of closantel and rafoxanide were characterised by a rapid distribution (t1/2(alpha)) of <30 min), long elimination half-life (t1/2(beta)) of 17.0 +/- 4.0 days for closantel and 7.2 +/- 0.6 days for rafoxanide), small apparent volume of distribution (V(SS) of <0.15 l/kg) and a slow rate of total body clearance (Cl of <0.01 ml/min/kg). The area under the drug plasma concentration curve (AUC) of closantel at 5 mg/kg was nearly twice as large as that of rafoxanide at 7.5 mg/kg resulting from the slower t1/2(beta) observed with closantel compared to rafoxanide. Large individual differences were observed in the rate measurements of distribution (k12, k21 and t1/2(alpha)), whereas the parameters of elimination (k10, t1/2(beta) and Cl), were more consistent between animals. A dose proportional increase in AUC was observed for closantel administered at 5 and 15 mg/kg. A low, constant salivary concentration of closantel (mean of 0.04 +/- 0.05 microg/mL) and rafoxanide (mean of 0.07 +/- 0.04 microg/mL) was observed during the 24-h examination period after dosing.  相似文献   

17.
Pharmacokinetics of procainamide hydrochloride were studied in 2 groups of dogs. In a group of 6 dogs, procainamide was administered IV at a small dose of 8 mg/kg (group 1), and blood samples were obtained for 3.5 hours. In another group of 6 dogs, procainamide was administered IV and orally at an average dose of 25.5 mg/kg (group 2) in a crossover manner. Blood samples were obtained for 48 hours. In 2 dogs (previously used in part II), N-acetylprocainamide (NAPA) was administered IV at a dose of 10 mg/kg. Plasma samples were assayed for procainamide by fluorescence polarization immunoassay, and NAPA samples were assayed by high-performance liquid chromatography. In group 1, the elimination of procainamide was described by a 1-compartment, open pharmacokinetic model. The elimination half-life was 2.43 hours, the apparent volume of distribution was 1.44 L/kg, and the systemic clearance was 0.412 L/kg/hr. In group 2, 2 of the 6 dogs were described by a 1-compartment model, and 4 of the 6 dogs were described with a 2-compartment pharmacokinetic model. The elimination half-life for the IV dosage was 2.85 hours, the apparent volume of distribution was 2.13 L/kg, and the systemic clearance was 0.519 L/kg/hr. For the orally administered dose, the bioavailability was 85%, and the absorption half-life was 0.5 hours. There was no evidence of acetylation of procainamide to NAPA or deacetylation of NAPA to procainamide. The estimated elimination half-life of NAPA was 4.7 hours.  相似文献   

18.
The pharmacokinetic properties of marbofoxacin, a third generation fluoroquinolone, were investigated in 12 healthy adult cats after single subcutaneous (SC) administration of 2 mg/kg BW (Part I, n=8 cats) and 4 mg/kg BW (Part II, n=4 cats). In each part of the study blood and urine samples were collected before treatment and thereafter for 5 days. The plasma and urine concentrations of marbofloxacin were determined by HPLC with UV detection. Pharmacokinetic calculations were performed for each treated animal using an open one-compartment-model with first-order elimination after SC dosing. Marbofloxacin in plasma (means): Maximum concentrations (Cmax) of about 1.2 and 3.0 microg/ml were measured 2.3 and 4 hours (tmax) after dosing of 2 and 4 mg/kg BW, respectively. Elimination from the body was low with a total clearance (Cl/F) of approximately 0.1 l/h/kg for both dosages. The half-life (t 1/2) for this process was calculated with 8-10 hours. AUC increased almost proportional when doubling the dose, i.e., 19.77 +/- 6.25 microg * h/ml (2 mg/kg BW) and 51.26 +/- 11.83 microg * h/ml (4 mg/kg BW). Plasma kinetics measured were in accordance with data from literature. Marbofloxacin in urine (means): Maximum drug concentrations were detected 4 and 8 hours after dosing with 70 microg/ml (2 mg/kg BW) and 160 microg/ml (4 mg/kg BW), respectively. Inhibitory effects of the urinary matrix on the antimicrobial activity of the drug were taken into account when performing PK/PD calculations. However, a concentration-dependent bactericidal activity (Cmax/MIC > 8-10) which is claimed for fluoroquinolones was sufficiently met with focus on Escherichia (E.) coli (MIC90 0.5 microg/ml). In the same matrix a threshold value of 1.0 microg/ml was undercut 82 and 116 hours after SC dosing, respectively. Hence, a time-dependent bacteria killing kinetic (T > MIC) which may be of relevance for some Gram-positive germs like Staphylococcus spp. (MIC90 1.0 microg/ml) should be covered, too.  相似文献   

19.
This study evaluated the pharmacokinetics of florfenicol in the white-spotted bamboo shark (Chiloscyllium plagiosum). In addition to the pharmacokinetics, the potential application for treatment of bacterial meningitis was explored. A pilot study was used to compare doses of 30, 40, and 50 mg/kg i.m. Following that study, 10 adult sharks were administered a single i.m. dose of florfenicol at 40 mg/kg. Plasma and cerebrospinal fluid were collected and analyzed for florfenicol by a sensitive and specific high-pressure liquid chromatographic method. Pharmacokinetic analysis was performed using both non-compartmental and compartmental techniques. The absorption produced an average peak at 54 (+/-19) hr from the i.m. site of administration, and the half-life was prolonged, averaging 269.79 hr (+/-135.87). Florfenicol plasma concentrations peaked at an average of 11.85 microg/ml (+/-1.45) and were maintained above our target minimum inhibitory concentration of 4-8 microg/ml for at least 120 hr. Cerebrospinal fluid concentrations peaked at an estimated 9 microg/ml around 48 hr, surpassing the target minimum inhibitory concentration for at least 72 hr.  相似文献   

20.
The pharmocodynamics of single injections of florfenicol in yearling loggerhead sea turtles (Caretta caretta) were determined. Eight juvenile loggerhead sea turtles weighing 1.25 (+/- 0.18) kg were divided into two groups. Four animals received 30 mg/kg of florfenicol i.v., and four received the same dose i.m. Plasma florfenicol concentrations were analyzed by reverse-phase high performance liquid chromatography. After the i.v. dose, there was a biphasic decline in plasma florfenicol concentration. The initial steep phase from 3 min to 1 hr had a half-life of 3 min, and there was a longer slow phase of elimination, with a half-life that ranged from 2 to 7.8 hr among turtles. The volume of distribution varied greatly and ranged from 10.46 to -60 L/kg. Clearance after the i.v. dose was 3.6-6.3 L/kg/hr. After the i.m. injection, there was a peak within 30 min of 1.4-5.6 microg/ml, and florfenicol was thereafter eliminated with a half-life of 3.2-4.3 hr. With either route, florfenicol plasma concentrations were below the minimum inhibitory concentrations for sensitive bacteria within 1 hr. Florfenicol does not appear to be a practical antibiotic in sea turtles when administered at these doses.  相似文献   

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