Ⅱ、生物利用度一、药物的胃肠道吸收 (一)膜生理学;pH 胃肠道屏障是由夹于蛋白质之间的双分子脂质层组成,其中脂质分子与细胞的表面相垂直。药物分子在胃肠道的吸收涉及到分子透过上皮细胞膜而进入血液或淋巴的转运作用。脂质膜上有半径约4A的含水的微孔,这种含水微孔不能用显微镜观察到。微孔这个专门术语是指膜的高度极性部位,该部位的水性比其他脂质部位更甚,半径相等或小于4A的小分子 Ⅱ, bioavailability First, the gastrointestinal absorption of drugs (A) membrane physiology; pH ​​The gastrointestinal barrier is composed of bilayer lipid layer sandwiched between proteins, in which the lipid molecules and the cell surface perpendicular to. Drug molecules in the gastrointestinal tract absorption involves molecules through the epithelial cell membrane and into the blood or lymph transport. The lipid membrane has a water-containing micropore about 4 A in radius, which can not be observed microscopically. Microporous This term refers to the highly polar parts of the membrane, the site of water more than other lipid sites, a radius of equal to or smaller than 4A small molecules