安定性同位素方法在生體可用率之應用已被肯定,尤其是在高度變數藥物(如高度第一次肝代謝及高度代謝)的應用,最近這方法已被應用在生體相等性的決定,當決定兩個非靜脈注射的劑型的生物相等性時,可在每次給藥時同時用靜脈注射安定性同位素之藥物,此方法可決定每次給藥時之清除率,本報告討論安定性同位素方法之優點和缺點,及其在高度變數藥物之劑型(如皮膚貼劑)在生體可用率及生體相等性之應用。
The stable isotope method has been used successfully in bioavailability studies for highly variable drugs that have extensive first-pass metabolism and exhibit large intra-subject variation in clearance. Recently this technique has been extended to bioequivalence studies where labeled solution is intravenously infused in both occasions while test and reference formulation are administered. This report discusses the advantages and disadvantages of the stable isotope method and its application in bioavailability and bioequivalence studies of highly variable drugs and drug delivery systems.