Division of Pharmaceutical Sciences, College of Pharmacy, University of Cincinnati, 3225 Eden Ave., 136 HPB, Cincinnati, Ohio 45267, USA.
J Pharm Sci. 2010 Apr;99(4):1955-67. doi: 10.1002/jps.21984.
The present study investigated the effects of pH on nail permeability and the transport of ions such as sodium (Na) and chloride (Cl) ions endogenous to nail and hydronium and hydroxide ions present at low and high pH, which might compete with drug transport across hydrated nail plate during iontophoresis. Nail hydration and passive transport of water across the nail at pH 1-13 were assessed. Subsequently, passive and iontophoretic transport experiments were conducted using (22)Na and (36)Cl ions under various pH conditions. Nail hydration was independent of pH under moderate pH conditions and increased significantly under extreme pH conditions (pH >11). Likewise, nail permeability for water was pH independent at pH 1-10 and an order of magnitude higher at pH 13. The results of passive and iontophoretic transport of Na and Cl ions are consistent with the permselective property of nail. Interestingly, extremely acidic conditions (e.g., pH 1) altered nail permselectivity with the effect lasting several days at the higher pH conditions. Hydronium and hydroxide ion competition in iontophoretic transport was generally negligible at pH 3-11 was significant at the extreme pH conditions studied.
本研究考察了 pH 值对指甲渗透性的影响，以及在低 pH 值和高 pH 值下内源性存在于指甲中的钠离子 (Na) 和氯离子 (Cl) 等离子以及水合氢离子和氢氧根离子的传输情况，这些离子可能会在离子电渗过程中与药物在水合指甲板中的传输竞争。评估了 pH 值为 1-13 时指甲的水化和水在指甲中的被动传输。随后，在不同 pH 值条件下使用 (22)Na 和 (36)Cl 离子进行被动和离子电渗传输实验。在适度 pH 值条件下，指甲的水化作用与 pH 值无关，而在极端 pH 值条件下（pH >11）则显著增加。同样，在 pH 值为 1-10 时，水在指甲中的被动渗透率与 pH 值无关，而在 pH 值为 13 时则高出一个数量级。Na 和 Cl 离子的被动和离子电渗传输结果与指甲的选择渗透性一致。有趣的是，极酸性条件（例如 pH 值 1）改变了指甲的选择渗透性，这种影响在较高 pH 值条件下持续数天。在研究的极端 pH 值条件下，水合氢离子和氢氧根离子在离子电渗传输中的竞争通常可以忽略不计，但在 pH 值 3-11 时则非常显著。
