国我私特 ©i生Introduction and concept Drugs are most often introduced into the body by the oral route of administration. ORAL ABSORPTION Drug absorption is the penetration of the drug School of Pharmacy across the intestinal "membrane"and its Chen Jian appearance,unchanged in the blood draining 2013.3 the GIT. chenjian@situ.edu.cn 国生一 Terms 国人烧 Pathways of drug absorption 国GlT:gastrointestinal tract胃肠道 ©Bioavailability生物利用度 ©Drug concentration--time curve药时曲线 ®AUC:area under the curve曲线下面积 国Cmax达峰值 国Tma达峰时 ④Fluid mosaic modeli流动镶嵌模型 The basic structure of the membrane is lipid bilayer. .There are proteins on or in the membrane. The membrane is semipermeable. 圈生一 Oral absorption 国tt线Pathways of drug absorption Introduction and concept of absorption Drugs are absorbed in different ways across the epithelial Anatomical and physiological consideration of boundary between the GIT and the bloodstream GIT ·Endocytosis内吞 Factors influencing drug absorption and drug availability ·Paracellular Diffusion(Pore transport膜孔转运) Physicochemical factors ·Passive diffusion被动扩散 Physiological factors ·Active transport主动转运 ·Other factors ·Facilitated diffusion促进转运 11 ORAL ABSORPTION School of Pharmacy Chen Jian 2013.3 chenjian@sjtu.edu.cn Shanghai Jiao Tong University Terms GIT: gastrointestinal tract胃肠道 Bioavailability 生物利用度 Drug concentration-time curve药时曲线 AUC: area under the curve曲线下面积 Cmax达峰值 Tmax达峰时 Shanghai Jiao Tong University Oral absorption Introduction and concept of absorption Anatomical and physiological consideration of GIT Factors influencing drug absorption and drug availability • Physicochemical factors • Physiological factors • Other factors Shanghai Jiao Tong University Introduction and concept Drugs are most often introduced into the body by the oral route of administration. Drug absorption is the penetration of the drug across the intestinal “membrane” and its appearance, unchanged in the blood draining the GIT. Shanghai Jiao Tong University Pathways of drug absorption Fluid mosaic model流动镶嵌模型 • The basic structure of the membrane is lipid bilayer. • There are proteins on or in the membrane. • The membrane is semipermeable. Shanghai Jiao Tong University Pathways of drug absorption Drugs are absorbed in different ways across the epithelial boundary between the GIT and the bloodstream • Endocytosis内吞 • Paracellular Diffusion (Pore transport膜孔转运) • Passive diffusion被动扩散 • Active transport主动转运 • Facilitated diffusion促进转运