Turner N G, Ferry L, Price M, Cullander C, Guy R H
Department of Biopharmaceutical Sciences, University of California-San Francisco 94143-0446, USA.
Pharm Res. 1997 Oct;14(10):1322-31. doi: 10.1023/a:1012100100865.
(1) To determine the extent of iontophoretic transport as a function of molecular weight (MW) of the penetrant; and (2) to visually and quantitatively characterize the iontophoretic transport pathways (follicular (F) versus nonfollicular (NF) of the fluorescently-labeled poly-L-lysines employed.
A series of fluorescently-labeled poly-L-lysines (FITC-PLLs) [4 KDa, 7 KDa and 26 KDa] were used to study the extent and distribution of iontophoretic skin penetration as a function of MW using laser scanning confocal microscopy (LSCM).
It was found that, relative to the passive controls, and under the electrical conditions considered, iontophoresis greatly enhanced the penetration of the 4 KDa analog, slightly elevated the delivery of the 7 KDa FITC-PLL, but had no effect on the transport of the larger 26 KDa FITC-PLL. Quantitative analyses of LSCM images revealed that iontophoresis increased transport via F pathways only slightly more than that through NF pathways for the 4 KDa and 7 KDa FITC-PLL molecules.
It is visually apparent that the iontophoretic transport pathways taken are importantly determined by the physicochemical properties (including size and charge) of the penetrant. The results presented here demonstrate an inverse dependence of iontophoretic delivery upon the MW of the penetrant.
（1）确定离子导入转运程度与渗透剂分子量（MW）之间的关系；（2）从视觉和定量角度表征所使用的荧光标记聚-L-赖氨酸的离子导入转运途径（滤泡性（F）与非滤泡性（NF））。
使用一系列荧光标记的聚-L-赖氨酸（FITC-PLLs）[4 kDa、7 kDa和26 kDa]，通过激光扫描共聚焦显微镜（LSCM）研究离子导入皮肤渗透的程度和分布与分子量的关系。
研究发现，相对于被动对照组，在所考虑的电学条件下，离子导入极大地增强了4 kDa类似物的渗透，略微提高了7 kDa FITC-PLL的递送，但对更大的26 kDa FITC-PLL的转运没有影响。对LSCM图像的定量分析表明，对于4 kDa和7 kDa FITC-PLL分子，离子导入通过F途径的转运仅比通过NF途径的转运略有增加。
从视觉上看很明显，所采用的离子导入转运途径主要由渗透剂的物理化学性质（包括大小和电荷）决定。此处呈现的结果表明离子导入递送与渗透剂的分子量呈反比关系。
