| Cefetamet Hydrochloride injection is prepared by the Hefei Yigong Medicine Co., Ltd. company. Our present work aims to comprehensively evaluate the pre-clinical pharmacokinetics of Cefetamet Hydrochloride injection. We have developed and validated a sensitive and reliable high-performance liquid chromatography (HPLC) method to determinate the concentration of cefetamet in plasma, excreta and tissues of rat. We initially identified the disposition process of the drug in vivo. The results provided a solid basis for the clinical research of Cefetamet Hydrochloride injection.Different analytical and sample preparation methods are used in various biological matrixes, enumerated as follows:(a). Analytical method of plasma sample of rat, tissue sample of rat and plasma sample of human:biological samples were pretreated by simple protein precipitation. The analysts were separated on a Dionex C18column eluted at a flow rate of1.0ml/min with a mobile phase of methnol-10mmol/L monopotassium phosphate buffer (with0.05%formic acid)(25:75, v/v); column temperature:30℃; wavelength of UV detection:262nm. Norfloxacin was chose as IS.(b). Analytical method of buffer sample:buffer samples were pretreated by high speed centrifugation. The analysts were separated on a Dionex C18column eluted at a flow rate of1.0ml/min with a mobile phase of methnol-10mmol/L monopotassium phosphate buffer (with0.05%formic acid)(35:65,v/v); column temperature:30℃; Wavelength of UV detection:262nm. Norfloxacin was chose as IS.(c). Analytical method of excretes:urine, feces and bile were pretreated by different methods. The analysts were separated on a Ultimate C18column eluted with a mobile phase of methnol-monopotassium phosphate buffer (with0.05%formic acid);column temperature:30℃.According to pre-clinical research technical guidelines for chemicals, we carried out overall methodological validation, the specificity, linearity, accuracy, precision, recovery, dilution effect and stability satisfied the requirements of the guidelines. The method has been successfully applied to the preclinical pharmacokinetic studies on Cefetamet Hydrochloride injection. Results are enumerated as follows:(a). We carried out the experiment by intravenous three dose (2.5,5.0, and10.0mg/Kg) administrations of cefetamet for pharmacokinetic study in rats. The validated HPLC method was used to determine the concentration of cefetamet in the plasma. Pharmacokinetic parameters were estimated by the non-compartment model.The pharmacokinetic parameters Co, ti/2, MRT, Clτ, Vd, AUC0-∞of six rats administrated cefetamet (25mg/Kg) were respectively248.99±54.52μg/ml、0.72±0.09h、0.97±0.11h、0.30±0.03L/h/Kg、0.29±0.02L/Kg、84.54±8.85μg-h/ml. The pharmacokinetic parameters Co, t1/2, MRT, Clτ, Vd, AUC0-∞of six rats administrated cefetamet (50mg/Kg) were respectively587.88±64.54μg/ml、0.81±0.24h、0.76±0.24h、0.37±0.06L/h/Kg、0.28±0.06L/Kg、137.08±23.74μg-h/ml.The pharmacokinetic parameters Co, t1/2, MRT, Clτ, Vd, AUC0-∞of six rats administrated cefetamet (75mg/Kg) were respectively796.54±93.30μg/ml、0.95±0.23h、0.66±0.08h、0.36±0.03L/kg、0.24±0.04L/kg、207.16±18.77μg·h/ml.(b). Tissues samples were collected after a single intravenous dose of50mg/Kg to rats. The validated HPLC method was used to determine the concentration of cefetamet in the tissue samples.The results showed that after intravenous administration of cefetamet hydrochloride injection (50mg/Kg), concentration of cefetamet in the kidney was the highest, while liver, lung, stomach and fat, was followed by the heart, spleen and brain.(c). Rat and human plasma protein binding were determined by equilibrium dialysis (72h) at4℃with final concentrations of1μg/ml、5μg/ml and16μg/ml. After the dialysis, the concentrations of cefetamet were determined by HPLC method. The results indicated the mean extent of binding to plasma proteins in human and appeared to be independent of concentration of used. The rat plasma and human plasma protein binding percentage of the drug was respectively about34%and27%.(d). Excretion of cefetamet after intravenous administration (50mg/Kg). Accumulation excretion amount of cefetamet were5403.59±1052.68μg,820.35±296.06μg and3344.23±227.82μg. |
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