Lopez Renata F V, Bentley M Vitória L B, Begoña Delgado-Charro M, Guy Richard H
Centre International de Recherche et d'Enseignement, Archamps, France.
J Control Release. 2003 Feb 14;88(1):65-70. doi: 10.1016/s0168-3659(02)00456-x.
The objective was to optimize aminolevulinic acid (ALA) electrotransport into and through the skin by adjustment of formulation composition and ionic strength. ALA delivery was investigated as a function of the polarity and concentrations of drug and background electrolyte in the donor solution. The anodal iontophoretic flux of ALA from a 10% solution was compared with the drug's passive flux from the same formulation to which 5% dimethyl sulphoxide (DMSO) had been added. Iontophoresis of the predominantly zwitterionic ALA from the anode is more efficient than that from the cathode. It was possible, though, to increase the electrotransport of ALA by simultaneously delivering the drug from both anode and cathode. Reduction of NaCl concentration in the anode led to a 3- to 4-fold increase in ALA flux. Transport of ALA across the skin and the amount of prodrug delivered into the skin (SC and [epidermis+dermis]) were approximately 4-fold greater with iontophoresis as compared to the passive application of the DMSO formulation.
(a) electroosmosis from the anode is enhanced when the background electrolyte concentration is lowered; and (b) low-level iontophoresis enhances ALA transport across and, more importantly, into the [epidermis+dermis] than a simple formulation incorporating DMSO.
目的是通过调整制剂组成和离子强度来优化氨基乙酰丙酸（ALA）向皮肤内及透过皮肤的电转运。研究了供体溶液中药物和背景电解质的极性及浓度对ALA递送的影响。将10%溶液中ALA的阳极离子导入通量与添加了5%二甲基亚砜（DMSO）的相同制剂中药物的被动通量进行了比较。从阳极进行离子导入时，两性离子为主的ALA的效率高于从阴极导入。不过，通过同时从阳极和阴极递送药物，可以增加ALA的电转运。阳极中NaCl浓度降低导致ALA通量增加3至4倍。与DMSO制剂的被动给药相比，离子导入时ALA透过皮肤的量以及递送至皮肤（角质层和[表皮+真皮]）中的前药的量大约高4倍。
（a）降低背景电解质浓度时，阳极的电渗作用增强；（b）与单纯含有DMSO的制剂相比，低水平离子导入增强了ALA穿过并更重要的是进入[表皮+真皮]的转运。
