Schnetz E, Fartasch M
Department of Dermatology, University of Erlangen, Hartmannstr 14, 91052, Erlangen, Germany.
Eur J Pharm Sci. 2001 Jan;12(3):165-74. doi: 10.1016/s0928-0987(00)00155-x.
The direct measurement of local drug concentration levels at discreet skin locations with minor trauma has recently become possible with the introduction of cutaneous microdialysis. Cutaneous microdialysis is an in vivo sampling technique for measuring solutes in the extracellular fluid of the dermis. When used in combination with other experimental approaches, for example with a variety of non-invasive techniques to describe the functional status of the skin (bioengineering methods), it may help investigators to gain new insights into the fields of skin diseases, metabolism and drug absorption/penetration. An important parameter to describe the efficacy of microdialysis is the relative recovery. This is the ratio between the concentration of a substance in the dialysate and the true extracellular concentration. Several methods are in common use to describe the relative recovery (no-net-flux method or retrodialysis). Parameters such as probe design, depth of the probe in the dermis, physico-chemical properties of the compound of interest, and analytical aspects are important factors influencing microdialysis. Microdialysis has been used to investigate the influence of penetration enhancers, vehicles or iontophoresis on percutaneous absorption, performed by in vivo studies in rats. In human volunteers, most of the experiments have been performed to study the kinetics of fast penetrating substances, e.g. nicotine, non-steroidal antiinflammatory drugs, local anaesthetics, or solvents. Problems have been encountered in the detection of lipophilic and highly protein-bound substances. Further, dermal metabolism and the influence of barrier perturbation on percutaneous absorption have been analyzed. Investigations suggest that microdialysis, in combination with traditional techniques, might give valuable information regarding the assessment of the penetration of drugs and other exogenous agents through the skin. In spite of the clearly defined and accepted advantages of microdialysis technology for studies of transdermal drug delivery, to date no standardized test procedure exists nor has the reproducibility of the results been evaluated. In the future, these problems have to be solved to enable this method to find its place in standard research.
随着皮肤微透析技术的引入，在微创情况下直接测量皮肤特定部位的局部药物浓度水平近来已成为可能。皮肤微透析是一种用于测量真皮细胞外液中溶质的体内采样技术。当与其他实验方法联合使用时，例如与各种描述皮肤功能状态的非侵入性技术（生物工程方法）相结合，它可能有助于研究人员在皮肤疾病、新陈代谢以及药物吸收/渗透等领域获得新的见解。描述微透析效能的一个重要参数是相对回收率。这是透析液中物质浓度与真实细胞外浓度的比值。有几种常用方法来描述相对回收率（无净通量法或反渗析法）。诸如探针设计、探针在真皮中的深度、目标化合物的物理化学性质以及分析方面等参数是影响微透析的重要因素。微透析已被用于通过大鼠体内研究来考察渗透促进剂、载体或离子导入对经皮吸收的影响。在人类志愿者中，大多数实验是为了研究快速渗透物质的动力学，例如尼古丁、非甾体抗炎药、局部麻醉剂或溶剂。在检测亲脂性和高蛋白结合物质时遇到了问题。此外，还分析了皮肤代谢以及屏障扰动对经皮吸收的影响。研究表明，微透析与传统技术相结合，可能会为评估药物和其他外源性物质透过皮肤的渗透提供有价值的信息。尽管微透析技术在透皮给药研究方面具有明确且公认的优势，但迄今为止尚无标准化的测试程序，结果的可重复性也未得到评估。未来，必须解决这些问题，以使该方法能在标准研究中占有一席之地。
