(Cephalexin)是口服之第一代頭孢菌素類(Cephalosporins)抗生素，臨床上用於治療呼吸道及泌尿道等細菌感染。在本研究中，主要在評估兩種cephalexin 250 mg膠囊劑，在健康國人體內的生體可用率。經由血中及尿中藥物濃度分析所得之藥物動力學參數，可以瞭解體內藥物的藥物動力學特性並比較兩種產品的相對生體可用率。 12位健康受試者接受此兩種產品的隨機雙向交叉研究，每人於試驗開始口服單劑量250 mg，依設定時間，收集血液及尿液檢品。利用高效液相層析法分析血漿中及尿中cephalexin的濃度。相關確效試驗，包括其同日、異日精確性，準確性，定量極限及安定性等，均在合理範圍之內。相對回收率亦大於95%。 結果顯示，cephalexin膠囊劑在國人口服後約0.86小時可達到最高血中濃度約10.99 ±1.93 μg/ml、平均半衰期(T1/2)約為1.23小時、平均曲線下面積(AUC0-∞)約19.34 ±3.65 μg · hr/ml。經由統計學二向變異數分析(Two-way ANOVA)結果，兩組產品的動力學參數，包括：Cmax、Tmax、T1/2、AUC0-∞及AUC0-10 等，結果發現並無統計學上的顯著差異(p>0.05)，因此可以認定試驗之Keflex?膠囊劑和Cephanmycin?膠囊劑兩產品是生體相等性的。尿中數據顯示cephalexin約有95%由尿中排泄。; Cephalexin is one of the first-generation of cephalosporin antibiotics given by oral route. Clinically , it is used in respiratory and urinary tract infections . In this study, the bioavailability of cephalexin from two capsule preparation in healthy Chinese male volunteers were evaluated. From calculated pharmacokinetic parameters, the possible bioequivalency of these two products were determined. Twelve healthy subjects received both products by randomized two-way crossover design. Within one day, each subject was administrated 250 mg doses before the test. The plasma and urine samples were collected all day. The concentrations of cephalexin in plasma samples were analyzed by high performance liquid chromatography (HPLC). The intra- and inter-day validation , limit of quantification and stability were reasonably with C.V. values less than 10%. The relative recovery was above 95%. The results showed Taiwan reaching peak concentration 10.99 ±1.93 μg/ml at about 0.86 hours. The mean half-life (T1/2) was about 1.23 hours. The mean area under the serum concentration curve (AUC0-∞) was about 19.34 ±3.65 μg · hr/ml. After analyzed by two-way ANOVA statistics, there are no significant statistic different between pharmacokinetic parameter (p<0.05) of two products, including the plasma concentration (Cmax), time to peak level (Tmax), the mean half-life (T1/2), and area under the curve (AUC). It could be recommened that Keflex? capsule and Cephanmycin? capsule are bioequivalent. The result also evidenced that there are about 95 % of cephalexin excreted unchangely from the urine.
