Sahota T S, Latham R J, Linford R G, Taylor P M
Solid State Research Center, Faculty of Applied Sciences, De Montfort University, Leicester, UK.
Drug Dev Ind Pharm. 1999 Mar;25(3):307-13. doi: 10.1081/ddc-100102175.
Polymer electrolytes are solid-like materials formed by dispersing a salt at the molecular level in a high molecular weight polymer such as poly(ethylene oxide) (PEO). They have been extensively studied for use in electrochemical applications such as batteries and display devices. This paper considers a novel application of polymer electrolytes as the basis of iontophoretic drug delivery systems. Polymer electrolyte films were cast from solutions of PEO and various drug salts using either water or an acetonitrile/ethanol mixture as the solvent. These films were characterized by variable-temperature polarizing microscopy (VTPM), differential scanning calorimetry (DSC), and alternating current (AC) impedance analysis. The films were around 100-micron thick and mechanically strong; the optical and thermal methods provided evidence that the polymer electrolytes had crystalline and amorphous phases, although some drugs may exist in films as nanodispersions. The amorphous phase is important as ions have greater mobility in this phase and therefore allow a current to be passed when the material is incorporated into a device such as one suitable for drug delivery by iontophoresis. The AC impedance analysis showed that the conductivity of the films varied between 10(-6) and 10(-3) S cm-1, depending on the salt, casting solvent, and temperature. Two drugs in particular were shown to be promising candidates in these systems: lidocaine hydrochloride and lithium chloride.
聚合物电解质是通过将盐在分子水平上分散在聚环氧乙烷（PEO）等高聚物中形成的类固体材料。它们已被广泛研究用于电池和显示设备等电化学应用中。本文考虑将聚合物电解质作为离子电渗药物递送系统的基础进行一种新的应用。使用水或乙腈/乙醇混合物作为溶剂，从PEO和各种药物盐的溶液中浇铸聚合物电解质膜。这些膜通过变温偏振显微镜（VTPM）、差示扫描量热法（DSC）和交流（AC）阻抗分析进行表征。这些膜厚度约为100微米且机械强度高；光学和热学方法提供了证据，表明聚合物电解质具有晶相和非晶相，尽管有些药物可能以纳米分散体的形式存在于膜中。非晶相很重要，因为离子在该相中具有更大的迁移率，因此当将该材料并入诸如适合通过离子电渗进行药物递送的装置中时，允许电流通过。交流阻抗分析表明，膜的电导率在10^(-6)至10^(-3) S cm^(-1)之间变化，这取决于盐、浇铸溶剂和温度。特别显示两种药物在这些系统中是有前景的候选药物：盐酸利多卡因和氯化锂。
