Chemical and Biological Engineering Department, Colorado School of Mines, Golden, CO 80401, USA.
Toxicol In Vitro. 2011 Dec;25(8):2095-104. doi: 10.1016/j.tiv.2011.09.011. Epub 2011 Sep 22.
The objective of this study was to quantitatively compare measurements of tritiated water permeability with impedance determined at either 100 or 1000 Hz using an LCR databridge on the same pieces of skin. A previously published expression based on a simple circuit of a parallel resistor and constant phase element (CPE) was used to relate (RPARA) measured at different frequencies to the DC resistance (RskinA) and the steady-state skin permeability of tritiated water (kp). Using this analysis, kp and (RPARA) data from three laboratories were shown to be consistent with each other, and kp and (RskinA) estimated from (RPARA) were linearly correlated. Compared with urea and mannitol, which are known to permeate skin through a polar pathway, the value of kp for water was found to be about two times larger than expected for transport through only the polar pathway, suggesting an approximately equal contribution from the lipophilic pathway. Equations relating kp to (RPARA) and (RskinA) were used to compare on a consistent basis proposed tests for identifying and excluding damaged skin from chemical absorption studies. The criterion of 20 kΩ cm2 for (RskinA) corresponds to a tritiated water permeability of 3.2×10(-3) cm/h, which should exclude damaged skin without screening undamaged but higher permeability skin samples from study.
本研究的目的是定量比较使用 LCR 数据桥在同一样品皮肤分别于 100Hz 和 1000Hz 下测量的氚水渗透系数与阻抗。本研究使用了一种基于并联电阻器和恒相元件（CPE）的简单电路的先前发表的表达式，将不同频率下测量的（RPARA）与 DC 电阻（RskinA）和氚水稳态皮肤渗透系数（kp）相关联。通过这种分析，三个实验室的 kp 和（RPARA）数据相互一致，并且可以从（RPARA）估计 kp 和（RskinA）。与已知通过极性途径渗透皮肤的尿素和甘露醇相比，水的 kp 值比仅通过极性途径运输时的预期值大约两倍，这表明亲脂性途径的贡献大致相等。用于将 kp 与（RPARA）和（RskinA）相关联的方程用于在一致的基础上比较拟议的测试，以识别和排除化学吸收研究中的受损皮肤。（RskinA）的 20kΩcm2 的标准对应于 3.2×10(-3)cm/h 的氚水渗透率，这应该可以排除受损皮肤，而不会筛选研究中未受损但具有更高渗透性的皮肤样本。
