The pharmacokinetics and dosage regimen of cefotaxime following its single subcutaneous administration (10 mg/ kg) were investigated in buffalo calves. Plasma and urine samples were collected over 10 and 24 h post administration, respectively. Cefotaxime in plasma and urine was estimated by microbiological assay technique using E. coli as test organism. The pharmacokinetic profiles fitted one-compartment open model. The peak plasma levels of cefotaxime were 6.48 +/- 0.52 microgram/ml at 30 min and the drug was detected upto 10 h. The absorption half-life and elimination halflife were 0.173 +/- 0.033 h and 1.77 +/- 0.02 h, respectively. The apparent volume of distribution and total body clearance were 1.17 +/- 0.10 l/kg and 0.45 +/- 0.03 l/kg/h, respectively. The urinary excretion of cefotaxime in 24 h, was 5.36 +/- 1.19 percent of total administrated dose. A satisfactory subcutaneous dosage regimen for cefotaxime in buffalo calves would be 13 mg/kg repeated at 12 h intervals.
Animals ; Anti-Bacterial Agents/*administration&dosage/blood/*pharmacokinetics/urine ; Area Under Curve ; *Buffaloes ; Cefotaxime/*administration&dosage/blood/*pharmacokinetics/urine ; Drug Administration Schedule ; Half-Life ; Male ; Tissue Distribution

The present study aimed to investigate the pharmacokinetic variation of ofloxacin based on gender-related difference in the expression of multidrug resistance-associated protein (Abcc2/Mrp2) in rat kidney. The concentrations of ofloxacin in rat plasma and urine were determined after tail vein administration (30 mg x kg(-1)) by high-performance liquid chromatography (HPLC) method. Expression of Mrp2 in kidney of male and female rats was qualitatively and quantitatively detected by immunohistochemistry and flow cytometry, separately. The results showed that AUC value of ofloxacin was lower in male rats than that in female rats and the total amount of ofloxacin excreted in the urine was higher in male rats than that in female rats. And the expression of Mrp2 in male rat kidney was higher than that in female rats. All results suggested that gender-related differences in pharmacokinetics of ofloxacin may be attributed to the differences in the expression of Mrp2 in kidney of male and female rats.
ATP-Binding Cassette Transporters ; metabolism ; Animals ; Anti-Bacterial Agents ; blood ; pharmacokinetics ; urine ; Area Under Curve ; Female ; Kidney ; metabolism ; Male ; Ofloxacin ; blood ; pharmacokinetics ; urine ; Rats ; Rats, Wistar ; Sex Characteristics

The pharmacokinetics and urinary excretion following single intramuscular administration of levofloxacin at a dose of 4 mg/kg was investigated in seven male cross bred calves. Appreciable plasma concentration of levofloxacin (0.38 +/- 0.06 microgram/ml) was detected at 1 min after injection and the peak plasma level of 3.07 +/- 0.08 microgram/ml was observed at 1 h. The drug level above MIC(90) in plasma was detected up to 12 h after administration. Rapid absorption of the drug was also evident by the high value of the absorption rate constant (2.14 +/- 0.24 /h). The overall systemic bioavailability of levofloxacin, after intramuscular administration, was 56.6 +/- 12.4%. The high value of AUC (7.66 +/- 0.72 mg.h/ml) reflected the vast area of body covered by drug concentration. Extensive distribution of the drug into various body fluids and tissues was noted by the high value of Vd(area) (1.02 +/- 0.05 l/kg). The high ratio of AUC/MIC (76.6 +/- 7.25) obtained in this study indicated excellent clinical and bacteriological efficacy of levofloxacin in calves. The elimination half-life and MRT were 3.67 +/- 0.4 h and 5.57 +/- 0.51 h, respectively. The total body clearance (Cl(B)) was 204.9 +/- 22.6 ml/kg/h. On the basis of the pharmacokinetic parameters, a suitable intramuscular dosage regimen for levofloxacin in calves would be 1.5 mg/kg repeated at 12 h intervals.
Animals ; Anti-Bacterial Agents/administration & dosage/blood/*pharmacokinetics/urine ; Area Under Curve ; Biological Availability ; Cattle/*metabolism/urine ; Half-Life ; Injections, Intramuscular/veterinary ; Male ; Ofloxacin/administration & dosage/blood/*pharmacokinetics/urine

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

BACKGROUNDA new fluroquinolone antibacterial agent, antofloxacin hydrochloride, developed in China, is an 8-NH(2) derivant of levofloxacin. The purpose of the study was to evaluate the pharmacokinetic characteristics of single and multiple oral doses of antofloxacin hydrochloride in Chinese healthy male volunteers.

METHODSAn open-label, non-randomized, single and multiple dose clinical trial was conducted. In single dose study, 12 subjects took 200 mg antofloxacin hydrochloride. In multiple dose study, 12 subjects took antofloxacin hydrochloride 400 mg once on day 1 and 200 mg once daily from day 2 to day 7. HPLC was used to assay the serum and urinary concentrations of antofloxacin.

RESULTSIn single dose study, the maximum concentration of drug in serum (C(max)), the time to reach C(max) (T(max)), and the area under the serum concentration-time curve (AUC (0-∞)) of antofloxacin were (1.89 ± 0.65) mg/L, (1.29 ± 0.26) hours, and (25.24 ± 7.26) mg×h(-1)×L(-1), respectively. Accumulating elimination rate of antoflocaxin from urine within 120 hours was 39.1%. In multiple dose study, blood concentration of antofloxiacin achieved stable state on day 2 after dosing. The minimum concentration drug in serum (C(min)), AUCss, mean concentration of drug in serum (C(av)), and degree of fluctuation (DF) were (0.73 ± 0.18) mg/L, (47.59 ± 7.85) mg×h(-1)×L(-1), (1.98 ± 0.33) mg/L, and 1.74 ± 0.60, respectively. On day 7 after dosing, T(max), C(max), and AUC (0-∞) was (1.14 ± 0.50) hours, (2.52 ± 0.38) mg/L, and (48.77 ± 8.44) mg×h(-1)×L(-1), respectively. Accumulating elimination rate of antofloxaxin from urine within 120 hours after the last dosing was 60.06%.

CONCLUSIONSThe regimen of 400 mg loading dose given on the first treatment day and then 200 mg dose once daily results in satisfactory serum drug concentration.

Administration, Oral ; Adolescent ; Adult ; Anti-Bacterial Agents ; administration & dosage ; blood ; pharmacokinetics ; urine ; Chromatography, High Pressure Liquid ; Humans ; Levofloxacin ; Male ; Ofloxacin ; administration & dosage ; analogs & derivatives ; blood ; pharmacokinetics ; urine ; Young Adult