2) Specialized transport mechanisms a This type of transport is thought to involve membrane components that may be enzymes or some other type of agent capable of forming a complex with the drug at the surface membrane, after which the complex moves across the membrane where the drug is released, with the carrier returning to the original surface (这种类型的转运认为需要涉及一些生物膜的成 分,可能是酶或其他能与药物在膜表面结合成复 合物的物质。复合物能移动到膜的另一侧并释放 出药物,载体则重新回到膜的表面。)
2) Specialized transport mechanisms ◼ This type of transport is thought to involve membrane components that may be enzymes or some other type of agent capable of forming a complex with the drug at the surface membrane, after which the complex moves across the membrane where the drug is released, with the carrier returning to the original surface. （这种类型的转运认为需要涉及一些生物膜的成 分，可能是酶或其他能与药物在膜表面结合成复 合物的物质。复合物能移动到膜的另一侧并释放 出药物，载体则重新回到膜的表面。）
This type of transfer seems to account for those substances many naturally occurring as amino acids and glucose, that are too lipid-insoluble to dissolve in the boundary and D too large to flow or filter through the pores (这种转运方式可以用来解 outside membrane Inside 释某些物质的转运,如许多 Actioe tramsport mechanisn. D represents a dr 天然存在的氨基酸和葡萄糖 from O Reily W. Aust J Pharm 1966: 47. 568) 有些是脂溶性很小在生物膜 中不能溶解或分子很大不能 通过膜上的孔道。)
This type of transfer seems to account for those substances, many naturally occurring as amino acids and glucose, that are too lipid-insoluble to dissolve in the boundary and too large to flow or filter through the pores. （这种转运方式可以用来解 释某些物质的转运，如许多 天然存在的氨基酸和葡萄糖， 有些是脂溶性很小在生物膜 中不能溶解或分子很大不能 通过膜上的孔道。）
Extracellular fluid Lipid-insoluble solute Carrier protein Cytoplasm
Active transport denotes a process of the solute or drug being moved across the membrane against a concentration gradient, that is, from a solution of lower concentration to one of a higher concentration or, if the solute is an ion, against an electrochemical potential gradient. (主动转运是指溶质或药物穿过生物膜的转运的过 程是逆浓度梯度进行,即从低浓度向高浓度转运 或当溶质是离子时逆电化学电势梯度转运。)
◼ Active transport denotes a process of the solute or drug being moved across the membrane against a concentration gradient, that is, from a solution of lower concentration to one of a higher concentration or, if the solute is an ion, against an electrochemical potential gradient. （主动转运是指溶质或药物穿过生物膜的转运的过 程是逆浓度梯度进行，即从低浓度向高浓度转运 或当溶质是离子时逆电化学电势梯度转运。）
Na Na Na Na Na Na Extracellular fluid N a K Na Na Na K binding Ites K Na Na Na AP Sodium-potassium K pump Na K Na+ Na K binding K sites K K Cytoplas K K