3. The aqueous solubility of a drug determines the concentration presented to the absorption site, and the partition coefficient influences the rate of transport across the absorption site 药物的水溶性决定了吸收部位的浓度,分配系 数影响吸收部位的药物转运速率。 Drugs generally penetrate the skin better in their un-ionized form. Nonpolar drugs tend to across the cell barrier through the lipid-rich regions, whereas the polar drugs favor transport between ces。 料跨牌的橙跨邀翻随走极精额栓磊拐 非 过 则通过细胞转运。3. The aqueous solubility of a drug determines the concentration presented to the absorption site, and the partition coefficient influences the rate of transport across the absorption site. 药物的水溶性决定了吸收部位的浓度，分配系 数影响吸收部位的药物转运速率。 Drugs generally penetrate the skin better in their un-ionized form. Nonpolar drugs tend to across the cell barrier through the lipid-rich regions, whereas the polar drugs favor transport between cells. 非解离型的药物透皮效果好。非极性药物易通 过富含脂质的部位跨越细胞屏障，而极性药物 则通过细胞转运