A study of amoxicillin pharmacokinetics was conducted in healthy goats and goats with chronic lead intoxication. The intoxicated goats had increased serum concentrations of liver enzymes (alanine aminotransferase and gamma-glutamyl transferase), blood urea nitrogen, and reactivated delta-aminolevulinic acid dehydratase compared to the controls. Following intravenous amoxicillin (10 mg/kg bw) in control and lead-intoxicated goats, elimination half-lives were 4.14 and 1.26 h, respectively. The volumes of distribution based on the terminal phase were 1.19 and 0.38 L/kg, respectively, and those at steady-state were 0.54 and 0.18 L/kg, respectively. After intramuscular (IM) amoxicillin (10 mg/kg bw) in lead-intoxicated goats and control animals, the absorption, distribution, and elimination of the drug were more rapid in lead-intoxicated goats than the controls. Peak serum concentrations of 21.89 and 12.19 microg/mL were achieved at 1 h and 2 h, respectively, in lead-intoxicated and control goats. Amoxicillin bioavailability in the lead-intoxicated goats decreased 20% compared to the controls. After amoxicillin, more of the drug was excreted in the urine from lead-intoxicated goats than the controls. Our results suggested that lead intoxication in goats increases the rate of amoxicillin absorption after IM administration and distribution and elimination. Thus, lead intoxication may impair the therapeutic effectiveness of amoxicillin.
Amoxicillin/blood/*pharmacokinetics/urine ; Animals ; Anti-Bacterial Agents/blood/*pharmacokinetics/urine ; Area Under Curve ; Chromatography, High Pressure Liquid/veterinary ; Goat Diseases/*chemically induced/metabolism ; Goats ; Half-Life ; Injections, Intramuscular/veterinary ; Injections, Intravenous/veterinary ; Lead Poisoning/etiology/metabolism/*veterinary ; Male

We investigated the disposition kinetics and urinary excretion of cefpirome in buffalo calves after a single intravenous administration of 10 mg/kg. Also, an appropriate dosage regimen was calculated. At 1 min after injection, the concentration of cefpirome in the plasma was 57.4 +/- 0.72 microgram/ml, which declined to 0.22 +/- 0.01 microgram/ml at 24 h. The cefpirome was rapidly distributed from the blood to the tissue compartment as shown by the high distribution coefficient values (8.67 +/- 0.46/h), and by the drug's rate of transfer constant from the central to the peripheral compartment, K12 (4.94 +/- 0.31/h). The elimination halflife and the volume of distribution were 2.14 +/- 0.02 h and 0.42 +/- 0.005 l/kg, respectively. Once the distribution equilibrium was reached between the tissues and plasma, the total body clearance (ClB) and the ratio of the drug present in the peripheral to the central compartment (T/P ratio) were 0.14 +/- 0.002 l/kg/h and 1.73 +/- 0.06, respectively. Based on the pharmacokinetic parameters we obtained, an appropriate intravenous cefpirome dosage regimen for treating cefpiromesensitive bacteria in buffalo calves would be 8.0 mg/kg repeated at 12 h intervals for 5 days, or until persistence of the bacterial infection occurred.
Animals ; Buffaloes/*metabolism/urine ; Cephalosporins/administration & dosage/*pharmacokinetics/*urine ; Injections, Intravenous/veterinary ; Kinetics ; Metabolic Clearance Rate/physiology

This study was performed to compare the effect of intratesticular (IT) injection of xylazine/ketamine combination for canine castration with those of intramuscular (IM) or intravenous (IV) injection. Xylazine and ketamine was administered simultaneously via intratesticularly (IT group), intramuscularly (IM group) or intravenously (IV group) at doses of 2 and 10 mg/kg, respectively. Pain response at the time of injection, mean induction time, mean arousal time, mean walking time and cardiopulmonary function during anesthesia were monitored after the xylazine and ketamine administration. In IV and IM groups, heart rates were significantly decreased 30 and 45 min after xylazine and ketamine administration, respectively (p < 0.05). Respiratory rates were significantly decreased in the IV group (p < 0.05). In the IT group, there was no significant changes in heart and respiratory rates. The occurrence of cardiac arrhythmias was less severe in IT group compared with those in IM and IV groups. The route of administration did not affect rectal temperature. Mean induction time was significantly (p < 0.05) longer in IT group than in IM and IV groups. On the contrary, mean arousal time and mean walking time were shortened in IT group. Clinical signs related to pain response at the time of injection and vomiting were less observed in IT group than in IM group, and head shaking was less shown in IT group than in IM and IV groups during recovery period. These results indicated that intratesticular injection of xylazine/ketamine for castration has several advantages such as less inhibition of cardiopulmonary function and fast recovery from anesthesia without severe complications, and would be an effective anesthetic method for castration in small animal practice.
Anesthesia, Intravenous/veterinary ; Anesthetics, Combined/adverse effects/*therapeutic use ; Anesthetics, Dissociative/adverse effects/*therapeutic use ; Animals ; Body Temperature/drug effects ; Castration/*veterinary ; Dogs ; Drug Administration Routes/veterinary ; Electrocardiography/drug effects/veterinary ; Heart Rate/drug effects ; Injections/veterinary ; Injections, Intramuscular/veterinary ; Ketamine/adverse effects/*therapeutic use ; Male ; Pain, Postoperative/prevention&control/veterinary ; Pulmonary Ventilation/drug effects ; Testis/*drug effects ; Vomiting/chemically induced/veterinary ; Xylazine/adverse effects/*therapeutic use

A bioavailability and pharmacokinetics study of doxycycline was carried out on 30 healthy ostriches after a single intravenous (IV), intramuscular (IM) and oral dose of 15 mg/kg body weight. The plasma doxycycline concentration was determined by HPLC/UV at 0 (pretreatment), 0.08, 0.25, 0.5 1, 2, 4, 6, 8, 12, 24 and 48 h after administration. The plasma concentration-time curves were examined using non-compartmental methods based on the statistical moment theory for only the higher dose. After IV administration, the elimination half-life (t(1/2beta)), mean residence time (MRT), volume of distribution at the steady-state (V(ss)), volume of distribution (Vd(area)) and total body clearance (Cl(B)) were 7.67 +/- 0.62 h, 6.68 +/- 0.86 h, 0.86 +/- 0.16 l/kg, 1.67 +/- 0.52 l/kg and 2.51 +/- 0.63 ml/min/kg, respectively. After IM and oral dosing, the mean peak plasma concentrations (C(max)) were 1.34 +/- 0.33 and 0.30 +/- 0.04 microgram/ml, respectively, which were achieved at a postadministration time (t(max)) of 0.75 +/- 0.18, 3.03 +/- 0.48 h, respectively. The t(1/2beta), Vd(area) and Cl(B) after IM administration were 25.02 +/- 3.98 h, 23.99 +/- 3.4 l/kg and 12.14 +/- 1.71 ml/min/kg, respectively and 19.25 +/- 2.53 h, 61.49 +/- 7 l/kg and 40.19 +/- 3.79 ml/min/kg after oral administration, respectively. The absolute bioavailability (F) of doxycycline was 5.03 and 17.52% after oral and IM administration, respectively. These results show that the dose data from other animals particularly mammals cannot be extrapolated to ostriches. Therefore, based on these results along with those reported in the literature, further studies on the pharmacokinetic/pharmacodynamic, in vitro minimum inhibitory concentration values and clinical applications of doxycycline in ostriches are required.
Administration, Oral ; Animals ; Anti-Bacterial Agents/administration & dosage/blood/*pharmacokinetics ; Area Under Curve ; Biological Availability ; Dose-Response Relationship, Drug ; Doxycycline/administration & dosage/blood/*pharmacokinetics ; Half-Life ; Injections, Intramuscular/veterinary ; Injections, Intravenous/veterinary ; Struthioniformes/*metabolism

Contrast-enhanced ultrasound is one of method for evaluating renal perfusion. The purpose of this project was to assess perfusion patterns and dynamics in normal micropig kidney using ultrasonographic contrast media. Eight young healthy micropigs were included in this study. Micropigs were anesthetized with propofol and received an intravenous bolus of microbubble contrast media through an ear vein. Time/mean pixel value (MPV) curves were generated for selected regions in the right renal cortex and medulla. The parenchyma was enhanced in two phases. The cortex was first enhanced followed by a more gradual enhancement of the medulla. A significant difference in perfusion was detected between the cortex and medulla. Following the bolus injection, the average upslope was 0.68 +/- 0.27 MPV/sec, downslope was -0.27 +/- 0.13 MPV/sec, baseline was 73.9 +/- 16.5 MPV, peak was 84.6 +/- 17.2 MPV, and time-to-peak (from injection) was 17.5 +/- 6.6 sec for the cortex. For the medulla, the average upslope was 0.50 +/- 0.24 MPV/sec, downslope was -0.12 +/- 0.06 MPV/sec, baseline was 52.7 +/- 7.0 MPV, peak was 65.2 +/- 9.3 MPV, and time-to-peak (from injection) was 27.5 +/- 5.0 sec. These data can be used as normal reference values for studying young micropigs.
Animals ; Contrast Media/*diagnostic use ; Image Processing, Computer-Assisted ; Injections, Intravenous/veterinary ; Kidney/*blood supply/ultrasonography ; Kidney Function Tests/veterinary ; Linear Models ; Microbubbles/diagnostic use/veterinary ; Reference Values ; Renal Circulation ; Sulfur Hexafluoride/diagnostic use ; Swine ; Swine, Miniature/*physiology ; Ultrasonography/*methods/veterinary

The disposition kinetics of levofloxacin was investigated in six male crossbred calves following single intravenous administration, at a dose of 4 mg/kg body weight, into the jugular vein subsequent to a single intramuscular injection of paracetamol (50 mg/kg). At 1 min after the injection of levofloxacin, the concentration of levofloxacin in plasma was 17.2 +/- 0.36 microgram/ml, which rapidly declined to 6.39 +/- 0.16 microgram/ml at 10 min. The drug level above the MIC90 in plasma, was detected for up to 10 h. Levofloxacin was rapidly distributed from blood to the tissue compartment as evidenced by the high values of the distribution coefficient, alpha (17.3 +/- 1.65 /h) and the ratio of K12/K21 (1.83 +/- 0.12). The values of AUC and Vdarea were 12.7 +/- 0.12 microgram.h/ml and 0.63 +/- 0.01 l/kg. The high ratio of the AUC/MIC (126.9 +/- 1.18) obtained in this study indicated the excellent antibacterial activity of levofloxacin in calves. The elimination half-life, MRT and total body clearance were 1.38 +/- 0.01 h, 1.88 +/- 0.01 h and 0.32 +/- 0.003 l/kg/h, respectively. Based on the pharmacokinetic parameters, an appropriate intravenous dosage regimen for levofloxacin would be 5 mg/kg repeated at 24 h intervals when prescribed with paracetamol in calves.
Acetaminophen/administration & dosage/*pharmacokinetics ; Animals ; Anti-Bacterial Agents/administration & dosage/blood/*pharmacokinetics ; Area Under Curve ; Cattle/*metabolism ; Drug Therapy, Combination ; Half-Life ; Hybridization, Genetic ; Injections, Intravenous/veterinary ; Male ; Ofloxacin/administration & dosage/blood/*pharmacokinetics ; Time Factors

The pharmacokinetics and dosage regimen of norfloxacin-glycine acetate (NFLXGA) was investigated in pigs after a single intravenous (i.v.) or oral (p.o.) administration at a dosage of 7.2 mg/kg body weight. After both i.v. and p.o. administration, plasma drug concentrations were best fitted to an open two-compartment model with a rapid distribution phase. After i.v. administration of NFLXGA, the distribution (t1/2alpha) and elimination half-life (t1/2beta) were 0.36 +/- 0.07 h and 7.42 +/- 3.55 h, respectively. The volume of distribution of NFLXGA at steady state (Vdss) was 4.66 +/- 1.39 l/kg. After p.o. administration of NFLXGA, the maximal absorption concentration (Cmax) was 0.43 +/- 0.06 microgram/ ml at 1.36 +/- 0.39 h (Tmax). The mean absorption (t1/2ka) and elimination half-life (t1/2beta) of NFLXGA were 0.78 +/- 0.27 h and 7.13 +/- 1.41 h, respectively. The mean systemic bioavailability (F) after p.o. administration was 31.10 +/- 15.16%. We suggest that the optimal dosage calculated from the pharmacokinetic parameters is 5.01 mg/kg per day i.v. or 16.12 mg/kg per day p.o.
Administration, Oral ; Animals ; Anti-Bacterial Agents/administration & dosage/blood/*pharmacokinetics ; Biological Availability ; Cross-Over Studies ; Glycine/administration & dosage/*analogs & derivatives/blood/pharmacokinetics ; Half-Life ; Injections, Intravenous/veterinary ; Male ; Norfloxacin/administration & dosage/*analogs & derivatives/blood/pharmacokinetics ; Swine/*metabolism ; Time Factors