| Summary: | 碩士 === 中國醫藥學院 === 藥物化學研究所 === 87 === Cephalexin is one of the first-generation of cephalosporin antibiotics given by oral route. It is used in respiratory and urinary tract infections and excretes in urine via kidney with original form completely. In this study, the bioavailability of cephalexin from two capsule preparation: Keflex(Lilly) and Cephanmycin (Yung Shin) in twelve healthy Chinese male volunteers were evaluated. From calculated pharmacokinetic parameters, the possible bioequivalency of these two products were determined. Also the urine sample was collected for to study the renal excretion mechanism of cephalexin.
We use both bioassay (cup-plate method with Sarcina lutea as test organism) and High performance liquid chromatography method (RP-18 column. Mobile phase is methanol: phosphate buffer=3:5, internal standard is cephradine. Monitoring at UV 260nm) to analysis the plasma and urine samples. Both methods showed good linearity, the intra- and inter-day validation is reasonably with the C.V. less than 10%. The relative recovery ratio is above 90%.
The elimination half-life of cephalexin in these twelve volunteers is about 1.1 hour, clearance is about 16 liters per hour, and area under the curve is about 30g.hr/ml. No obviously statistic difference was found in these two analysis method.
The result also evidenced that there are about 98% of cephalexin excreted unchangely from the urine.
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