Nino Massimiliano, Calabrò Gabriella, Santoianni Pietro
Department of Systematic Pathology, Section of Dermatology, Naples, Italy.
Dermatol Online J. 2010 Jan 15;16(1):4.
To be effective an active drug or principle must cross the stratum corneum barrier; this process can be influenced to obtain better functional and therapeutical effects. In spite of the wide variety of the methods studied in order to improve the transdermal transfer to obtain systemic effects, the applicability is limited in this field. Attention to the epidermal barrier and penetration of active principles has been reported mostly in studies concerning dermocosmetics. Studies regarding methods of penetration are gaining experimental and clinical interest. Cutaneous bioavailability of most commercially available dermatological formulations is low. Increase of intradermal delivery can relate to chemical, biochemical, or physical manipulations. Chemical enhancers have been adopted to: (a) increase the diffusibility of the substance across the barrier; (b) increase product solubility in the vehicle; (c) improve the partition coefficient. Moreover methods of interference with the biosynthesis of some lipids allow the modification of the structure of the barrier to increase the penetration. The main physical techniques that increase cutaneous penetration of substances are: iontophoresis (that increases the penetration of ionized substances), electroporation (that electrically induces penetration through the barrier), and sonophoresis, based on 20 to 25 KHz ultrasound that induces alterations of the horny barrier, allowing penetration of active principles. Recent development of these methods are here reported and underline the importance and role of vehicles and other factors that determine effects of partition and diffusion, crucial to absorption.
一种活性药物或成分要发挥作用，必须穿过角质层屏障；这一过程可受到影响，以获得更好的功能和治疗效果。尽管为改善透皮传递以获得全身效应研究了各种各样的方法，但该领域的适用性仍然有限。关于表皮屏障和活性成分渗透的研究大多报道于皮肤化妆品相关研究中。有关渗透方法的研究正引起实验和临床方面的关注。大多数市售皮肤科制剂的皮肤生物利用度较低。皮内给药量的增加可与化学、生化或物理操作有关。化学促进剂已被用于：（a）增加物质穿过屏障的扩散性；（b）增加产品在载体中的溶解度；（c）改善分配系数。此外，干扰某些脂质生物合成的方法可改变屏障结构以增加渗透性。增加物质皮肤渗透的主要物理技术有：离子导入法（增加离子化物质的渗透）、电穿孔法（通过电诱导穿过屏障）以及超声导入法，基于20至25千赫兹的超声波诱导角质屏障改变，使活性成分得以渗透。本文报道了这些方法的最新进展，并强调了载体及其他决定分配和扩散效果（对吸收至关重要）的因素的重要性和作用。
