药科大生物药剂学课件第二三章药物吸收详解演示文稿
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Active transport is a transport process of drug against a concentration gradient—that is, from regions of low drug conc. to regions of high conc.
一些机体必需的物质如，氨基 酸，单糖，Na+, K+及某些 维生素等的吸收通过此方式完 成。
膜上的蛋白质，具有生理功能，根据其在脂质双 分子层的不同位置可分为：
✓ 外在性蛋白，如ATP酶、己糖激酶等
✓ 内在性蛋白,如细胞色素C、药物的受体、特异 性载体等
➢膜的性质
✓ 选择性的屏障，生命所需要的物质如，AA、糖类、脂肪 酸等易通过
✓ 细胞膜的分子间及蛋白质的分子内存在细微含水孔道
✓ 为半渗透性膜，具有半透膜和双电层的性质，水和脂溶性 物质可通过，高度解离的分子和大分子如蛋白质和蛋白结 合的药物不能通过。
被动转运与主动转运比较
➢ Facilitated diffusion（促进扩散或易化扩散）
Facilitated diffusion is also a carrier-mediated transport system, differing from active transport in that the drug moves along a conc. gradient
Cell
Neutral Molecules
ቤተ መጻሕፍቲ ባይዱ
Diffusion
+
Charged Molecules
-
Ion Pair
+
-
Bulk Flow
+
Endocytosis
+ -
+-
- -+
Carrier Mediated (active and facilitated)
➢ Passive Diffusion（被动扩散）
非脂溶性或亲水性药物如，L赖氨酸,D-木糖,葡萄糖等 通 过此方式转运。
Characteristics
✓ This system does not require energy input. ✓ Because this system is carrier mediated, it may be
PH-partition hypotheses describes the relationship of the rate of drug transport with the extent of ionization and lipid soluble property of drug
➢ Active Transport（主动转运）
➢ Passive Diffusion ➢ Active Transport ➢ Facilitated diffusion ➢ Vesicular Transport ➢ Pore (Convective) Transport ➢ Ion Pair Formation and
Transport
Mechanisms of transport across membranes
Cell Membrane
Lipid polar head-group
Cytosol
Lipid Neutral hydrocarbon chain
➢膜的组成
类脂、蛋白质和少量多糖
➢ 膜的基本骨架
由流动的液态类脂双分子层所 组成 脂质分子的极性部分向外，非 极性部分向内，外侧为蛋白质 覆盖，膜上含有细孔，水分子 能自由通过
dQ/dt = rate of diffusion（扩散速度） D = diffusion coefficient（扩散系数） K = partition coefficient（分配系数） A = surface area of membrane（膜的表面积） h = membrane thickness（膜的厚度） CGI- CP = difference between the conc. of drug in the gastrointestinal tract and in the plasma （药物在胃肠道与血液之间的差异）
Passive diffusion is a process by which molecules spontaneously diffuse from a region of higher conc. to a region of lower conc.
药物的细胞转运途径：被动扩散
Fick’s law of diffusion dQ/dt = DAK (CGI- CP) /h
药科大生物药剂学课件第二三章 药物吸收详解演示文稿
（优选）药科大生物药剂学课件 第二三章药物吸收
II. Gastrointestinal Absorption
1. Nature of the epithelial cell membrane
➢膜的组成 ➢膜的基本骨架 ➢膜的性质
Extracellular Proteins
主动转运：钠、钾泵排放
Characteristics
✓ It is an energy-consuming system. ✓ It is a specialized process requiring a carrier. ✓ Drug of similar structure may compete for sites of
absorption on the carrier. ✓ Because only a certain amount of carrier is available, all
the absorption sites on the carrier may become saturated if the drug conc. gets very high.
Henderson Hasselbalch Equation
--to describe the relationship between pKa and pH ✓ For weak acids
✓ For weak bases
2．Passage of drugs across cell membranes
一些机体必需的物质如，氨基 酸，单糖，Na+, K+及某些 维生素等的吸收通过此方式完 成。
膜上的蛋白质，具有生理功能，根据其在脂质双 分子层的不同位置可分为：
✓ 外在性蛋白，如ATP酶、己糖激酶等
✓ 内在性蛋白,如细胞色素C、药物的受体、特异 性载体等
➢膜的性质
✓ 选择性的屏障，生命所需要的物质如，AA、糖类、脂肪 酸等易通过
✓ 细胞膜的分子间及蛋白质的分子内存在细微含水孔道
✓ 为半渗透性膜，具有半透膜和双电层的性质，水和脂溶性 物质可通过，高度解离的分子和大分子如蛋白质和蛋白结 合的药物不能通过。
被动转运与主动转运比较
➢ Facilitated diffusion（促进扩散或易化扩散）
Facilitated diffusion is also a carrier-mediated transport system, differing from active transport in that the drug moves along a conc. gradient
Cell
Neutral Molecules
ቤተ መጻሕፍቲ ባይዱ
Diffusion
+
Charged Molecules
-
Ion Pair
+
-
Bulk Flow
+
Endocytosis
+ -
+-
- -+
Carrier Mediated (active and facilitated)
➢ Passive Diffusion（被动扩散）
非脂溶性或亲水性药物如，L赖氨酸,D-木糖,葡萄糖等 通 过此方式转运。
Characteristics
✓ This system does not require energy input. ✓ Because this system is carrier mediated, it may be
PH-partition hypotheses describes the relationship of the rate of drug transport with the extent of ionization and lipid soluble property of drug
➢ Active Transport（主动转运）
➢ Passive Diffusion ➢ Active Transport ➢ Facilitated diffusion ➢ Vesicular Transport ➢ Pore (Convective) Transport ➢ Ion Pair Formation and
Transport
Mechanisms of transport across membranes
Cell Membrane
Lipid polar head-group
Cytosol
Lipid Neutral hydrocarbon chain
➢膜的组成
类脂、蛋白质和少量多糖
➢ 膜的基本骨架
由流动的液态类脂双分子层所 组成 脂质分子的极性部分向外，非 极性部分向内，外侧为蛋白质 覆盖，膜上含有细孔，水分子 能自由通过
dQ/dt = rate of diffusion（扩散速度） D = diffusion coefficient（扩散系数） K = partition coefficient（分配系数） A = surface area of membrane（膜的表面积） h = membrane thickness（膜的厚度） CGI- CP = difference between the conc. of drug in the gastrointestinal tract and in the plasma （药物在胃肠道与血液之间的差异）
Passive diffusion is a process by which molecules spontaneously diffuse from a region of higher conc. to a region of lower conc.
药物的细胞转运途径：被动扩散
Fick’s law of diffusion dQ/dt = DAK (CGI- CP) /h
药科大生物药剂学课件第二三章 药物吸收详解演示文稿
（优选）药科大生物药剂学课件 第二三章药物吸收
II. Gastrointestinal Absorption
1. Nature of the epithelial cell membrane
➢膜的组成 ➢膜的基本骨架 ➢膜的性质
Extracellular Proteins
主动转运：钠、钾泵排放
Characteristics
✓ It is an energy-consuming system. ✓ It is a specialized process requiring a carrier. ✓ Drug of similar structure may compete for sites of
absorption on the carrier. ✓ Because only a certain amount of carrier is available, all
the absorption sites on the carrier may become saturated if the drug conc. gets very high.
Henderson Hasselbalch Equation
--to describe the relationship between pKa and pH ✓ For weak acids
✓ For weak bases
2．Passage of drugs across cell membranes