Studies using cancer chemotherapeutic agents such as epirubicin encapsulated in liposomes, made of phospholipids and other ingredients, have generally shown reduced toxicity and enhanced therapeutic efficacy. This study investigated the effects of liposomal encapsulation,empty liposome or free lipid addition on the uptake and transport of epirubicin in the human colon adenocarcinoma (Caco-2) cell line. The flow cytometric experiments showed that liposomal encapsulation or empty liposome addition significantly increased the intracellular accumulation or epjrubicin in Caco-2 cells. Use of liposomes, made of dipalmitoyl phosphatidylcholine (DPPC), substantially enhanced apical to basolateral absorption of epirubicin across Caco-2 monolayers. Furthermore,except free DPPC addition, epirubicin encapsulated in DPPC liposomes or empty DPPC liposome addition significantly reduced the basolateral to apical efflux of epirubicin across Caco-2 mono-layers. The study suggests that inhibition of P-gp or other transporter proteins located in the intestines may be, at least partially, involved in the reduction of epirubicin efflux. In conclusion,the therapeutic efficacy of epirubicin may be improved by the use of phospholipids as excipients and MDR modulators in the formulations. Liposomal encapsulation may have significant implications to circumvent drug reslstance in cancer chemotherapy. 磷脂質常被用來當作藥物之攜帶體。抗癌藥物若以磷脂質做成之微脂粒包裝，常可降低毒性、增加療效。因此我們研究微脂粒包埋、空的微脂粒或磷脂質對於Epirubicin於人類結腸腺癌細胞(Caco-2)之積聚及運送之效應。使用流式細胞分析儀分析，發現微脂粒包埋或空的微脂粒明顯增進Epirubicin於Caco-2細胞之積聚。以Caco-2細胞為模型，發現微脂粒包埋或空的微脂粒可顯著促進Epirubicin於吸收方向之運輸及明顯減少Epirubicin於排出方向之運輸。實驗結果顯示抑制小腸P醣蛋白或其他排出藥物之蛋白質可能跟Epirubicin之增加吸收及減少排出有關。總結，使用磷脂質做成藥物之微脂粒劑型可以經由抑制P醣蛋白之機轉以促進藥物之小腸吸收，並增進P醣蛋白受質之生體可用率。微脂粒包裝可應用於拮抗癌症化學療法上之多重抗藥性。
