OBJECTIVE: To establish a new high performance liquid chromatography (HPLC) method for determining the concentration of cefazolin, cefradine, cefoperazone and cefotaxime in blood and urine, as well as to investigate its applicability. METHODS: Protein in blood and urine was precipitated directly by acetonitrile with acetanilide was used as the internal standard using Agilent Zorbax SB-Aq column (250 mm x 4.6 mm, 5 microm). The mixed solvents of water (triethylamine 0.12%, acetic acid 0.12%) and acetonitrile were used as the mobile phase to separate cephalosporins using gradient elution method at 1 mL/min (flow rate) and 254 nm (detection wavelength). RESULTS: The working curve of four cephalosporins showed a good correlation (r = 0.9993), with the detection limit up to 0.01 microg/mL. The recovery rate was more than 81.2%. CONCLUSION This method is fast, easy and accurate. It is suitable for biological analysis of the 4 cephalosporins of the blood and urine in practical cases.
Adult ; Anti-Bacterial Agents/urine* ; Cefazolin/urine* ; Cefoperazone/urine* ; Cefotaxime/urine* ; Cephalosporins/urine* ; Cephradine/urine* ; Chromatography, High Pressure Liquid/methods* ; Forensic Toxicology ; Humans ; Male ; Sensitivity and Specificity ; Specimen Handling

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