Smetanová Libuse, Stĕtinová Vĕra, Svoboda Zbynek, Kvetina Jaroslav
Institute of Experimental Biopharmaceutics, Joint Research Centre of PRO.MED.CS Praha.
Acta Medica (Hradec Kralove). 2011;54(1):3-8.
Almost all orally administered drugs are absorbed across the intestinal mucosa. The Caco-2 monolayers are used as an in vitro model to predict drug absorption in humans and to explore mechanism of drug absorption. The Caco-2 cells are derived from a human colon adenocarcinoma and spontaneously differentiate to form confluent monolayer of polarized cells structurally and functionally resembling the small intestinal epithelium. For studying drug permeability, Caco-2 cells are seeded onto the Transwell inserts with semipermeable membrane and grown to late confluence (21 days). After determination of cell viability, the integrity of monolayer is checked by phenol red permeability and by 14C-mannitol permeability. The transport from apical to basolateral (AP-BL) and basolateral to apical (BL-AP) is studied by adding the diluted drug on the apical or basolateral side and withdrawing the samples from the opposite compartment, respectively, for HPLC analysis or liquid scintillation spectrometry. Ca2+ -free transport medium is used to determine paracellular component of the drug transport. On the basis of permeability and solubility, drugs can be categorized into four classes of Biopharmaceutics Classification System (BCS). For certain drugs, the BCS-based biowaiver approach can be used which enables to reduce in vivo bioequivalence studies.
几乎所有口服给药的药物都是通过肠黏膜吸收的。Caco-2单层细胞被用作体外模型来预测人体药物吸收并探索药物吸收机制。Caco-2细胞源自人结肠腺癌，能自发分化形成结构和功能上类似于小肠上皮的极化细胞汇合单层。为研究药物通透性，将Caco-2细胞接种到带有半透膜的Transwell小室中并培养至汇合后期（21天）。在测定细胞活力后，通过酚红通透性和14C-甘露醇通透性检查单层的完整性。通过分别在顶侧或基底外侧加入稀释药物并从相对隔室中取出样品进行HPLC分析或液体闪烁光谱法，研究从顶侧到基底外侧（AP-BL）以及从基底外侧到顶侧（BL-AP）的转运。使用无Ca2+转运培养基来确定药物转运的细胞旁成分。基于通透性和溶解性，药物可分为生物药剂学分类系统（BCS）的四类。对于某些药物，可采用基于BCS的生物豁免方法，从而能够减少体内生物等效性研究。
