Turner N G, Guy R H
Department of Biopharmaceutical Sciences, University of California-San Francisco 94143-0446, USA.
J Pharm Sci. 1997 Dec;86(12):1385-9. doi: 10.1021/js970046z.
The objective of this work was to investigate how the preferred iontophoretic transport pathways of a molecule depend on its physicochemical properties. Laser scanning confocal microscopy (LSCM) was used to visualize in hairless mouse skin the distribution of two fluorescent penetrants: calcein, a multiply charged (-4), hydrophilic molecule; and nile red, a lipophilic, neutral compound. Iontophoresis and passive delivery of nile red showed that the percutaneous transport of this compound occurred via (inter- and intracellular) pathways that were clearly distinct from those followed by calcein. Although the distribution of nile red was influenced somewhat by the passage of current relative to the passive control, there was relatively little enhancement of the penetration of this compound into the skin. Calcein, on the other hand, did not passively enter the skin. However, with iontophoresis, greatly enhanced transport, with an important contribution from follicular structures, was observed. Sequential (dual) transport of the two fluorophores illustrated clearly the different pathways followed and reflected the transport and visualization studies of the individual species. It may be concluded, therefore, that the iontophoretic pathways followed across the skin are dictated by the physicochemical properties of the penetrant and by its affinity for the different environments available.
这项工作的目的是研究分子的首选离子导入传输途径如何取决于其物理化学性质。激光扫描共聚焦显微镜（LSCM）用于在无毛小鼠皮肤中可视化两种荧光渗透剂的分布：钙黄绿素，一种多电荷（-4）的亲水分子；以及尼罗红，一种亲脂性中性化合物。尼罗红的离子导入和被动递送表明，该化合物的经皮传输通过（细胞间和细胞内）途径进行，这些途径与钙黄绿素所遵循的途径明显不同。尽管相对于被动对照，电流的通过对尼罗红的分布有一定影响，但该化合物渗透到皮肤中的增强相对较小。另一方面，钙黄绿素不会被动进入皮肤。然而，通过离子导入，观察到其传输大大增强，毛囊结构起到了重要作用。两种荧光团的顺序（双重）传输清楚地说明了所遵循的不同途径，并反映了各个物种的传输和可视化研究。因此，可以得出结论，穿过皮肤的离子导入途径由渗透剂的物理化学性质及其对可用不同环境的亲和力决定。
