Cross S E, Roberts M S
Department of Medicine, University of Queensland, Princess Alexandra Hospital, Brisbane, Australia.
J Pharm Sci. 1995 May;84(5):584-92. doi: 10.1002/jps.2600840513.
The effect of dermal blood flow on the transdermal iontophoresis of five monovalent cationic solutes has been investigated using an in vivo rat model. The iontophoretic flux of solutes from topical application sites was shown, using anesthetized and sacrificed rats, to be independent of the dermal blood supply. The presence of a viable blood supply significantly affected the extent of penetration of solutes into deeper underlying tissues during iontophoresis. Higher tissue concentrations of solutes were found in the upper tissue layers of sacrificed rats, with no blood supply, compared to those in anesthetized rats. In all animals the highest concentration of solute after 2 h iontophoresis was found in the epidermis. Iontophoretic application of solutes to skin with the epidermis removed resulted in significantly lower fluxes than from sites where the skin was intact. These findings suggest that local blood flow determines systemic and underlying tissue solute absorption but not epidermal penetration fluxes during iontophoretic delivery. Finally, the dependence of iontophoretic transport of a solute on the solute's size in vivo was similar to relationships previously reported for excised human skin studies.
利用体内大鼠模型，研究了皮肤血流量对五种单价阳离子溶质经皮离子电渗疗法的影响。使用麻醉和处死后的大鼠表明，溶质从局部应用部位的离子电渗通量与皮肤血液供应无关。在离子电渗疗法期间，有活力的血液供应的存在显著影响溶质渗透到更深层组织的程度。与麻醉大鼠相比，在没有血液供应的处死后的大鼠的上层组织中发现溶质的组织浓度更高。在所有动物中，离子电渗2小时后溶质的最高浓度出现在表皮中。将溶质离子电渗应用于去除表皮的皮肤导致的通量明显低于皮肤完整部位。这些发现表明，局部血流决定了离子电渗给药期间全身和深层组织溶质的吸收，但不决定表皮渗透通量。最后，溶质在体内的离子电渗转运对溶质大小的依赖性与先前报道的人体皮肤离体研究的关系相似。
