Inada H, Mizuguchi K, Katayama K, Kakemi M, Koizumi T
Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Japan.
Biol Pharm Bull. 1993 Jun;16(6):589-93. doi: 10.1248/bpb.16.589.
Iontophoretic and passive transport of an ionized drug (sulfisoxazole) across excised rat skin was studied using a two-chamber cell with four electrodes under successive experimental conditions: without electrical current (stage-I) and with electrical current (stage-II). Two iontophoretic/diffusion models, i.e. a one-layer membrane model and a two-layer membrane model, in which a difference in the electrical potential gradient was taken into account between the stratum corneum and epidermis/dermis layer, were constructed to describe the non-steady-state drug permeation process during ionotrophoresis. The observed iontophoretic lag-time was two times greater than the calculated value based on the one-layer membrane model. According to the two-layer membrane model, the calculated ionotophoretic lag-time agreed with the observed value. It was revealed by model adaptation to the observed data that the stratum corneum fraction of the electro-chemical potential difference across the whole skin caused by the iontophoresis was around 90%. This result was consistent with the observation that the direct current resistance of whole skin was seven times greater than that of stripped skin.
使用具有四个电极的两室细胞，在连续的实验条件下研究了离子化药物（磺胺异恶唑）在切除的大鼠皮肤上的离子导入和被动转运：无电流（阶段 I）和有电流（阶段 II）。构建了两个离子导入/扩散模型，即单层膜模型和双层膜模型，其中考虑了角质层与表皮/真皮层之间的电位梯度差异，以描述离子导入过程中的非稳态药物渗透过程。观察到的离子导入滞后时间比基于单层膜模型计算的值大两倍。根据双层膜模型，计算出的离子导入滞后时间与观察值一致。通过对观察数据进行模型拟合发现，离子导入引起的整个皮肤电化学势差的角质层部分约为 90%。这一结果与全皮直流电阻是去皮皮肤直流电阻七倍的观察结果一致。
