Nanoscience and Technology Program Graduate School, Chulalongkorn University, Bangkok 10330, Thailand.
Langmuir. 2010 May 18;26(10):6869-73. doi: 10.1021/la1003676.
Polyelectrolyte multilayer (PEM) thin films prepared using the layer-by-layer technique are proposed as a matrix for the immobilization of 1,7-bis-(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-2,5-dione (curcumin), a lipophilic model drug. The PEM assembly was based on the layer-by-layer deposition of cationic poly(diallyldimethyl-ammonium chloride) (PDADMAC) and anionic poly(4-styrene sulfonate, sodium salt) (PSS) onto a quartz slide. Curcumin was loaded by dipping the PEM film into a dilute solution of curcumin dispersed in an 80/20% v/v water/ethanol solution. Within a few minutes, the film turned bright yellow as a result of the curcumin loading. The effect of the solvent composition, curcumin concentration and film thickness on the final concentration of curcumin in the PEM films was measured by UV-vis spectroscopy. The loading of curcumin was driven by its partitioning in the PEM film, and its partitioning coefficient between the 80/20 solvent and the PEM thin film was found to have a value of 2.07 x 10(5). The extinction coefficient of curcumin loaded into PEM was calculated to 64,000 M(-1) cm(-1). Results show that the loading of curcumin into the PEM films increased with the number of deposited layers, implying that curcumin partitioned into the bulk of the thin film. The maximum curcumin dose in the PEM film was measured by exposing films of various thicknesses to a high concentration (0.01% w/v) of curcumin and recording the maximum absorbance after saturation. The films thicknesses were controlled by the number of deposited PDADMAC/PSS layers (10, 20, 30, 40, 50, and 60). Results show that increasing amounts of curcumin could be loaded into the film with an increasing number of layers and up to 8 microg/cm(2) of curcumin could be loaded into a 20-layer film. These results demonstrate that the loading of lipophilic curcumin in PEM thin films is done through a partitioning mechanism and that the PDADMAC/PSS film can be used as a loading matrix for lipophilic drugs.
采用层层自组装技术制备的聚电解质多层（PEM）薄膜被提议作为固定 1,7-双（4-羟基-3-甲氧基苯基）-1,6-庚二烯-2,5-二酮（姜黄素）的基质，姜黄素是一种亲脂性模型药物。PEM 组装是基于阳离子聚二烯丙基二甲基氯化铵（PDADMAC）和阴离子聚（4-苯乙烯磺酸钠，钠盐）（PSS）在石英片上的层层沉积。将 PEM 薄膜浸入姜黄素在 80/20%v/v 水/乙醇溶液中分散的稀溶液中，即可负载姜黄素。几分钟内，由于负载姜黄素，薄膜变成亮黄色。通过紫外可见光谱法测量溶剂组成、姜黄素浓度和薄膜厚度对 PEM 薄膜中最终姜黄素浓度的影响。姜黄素的负载是由其在 PEM 薄膜中的分配驱动的，并且发现其在 80/20 溶剂和 PEM 薄膜之间的分配系数为 2.07x10(5)。计算出负载姜黄素的 PEM 的消光系数为 64,000 M(-1)cm(-1)。结果表明，负载姜黄素进入 PEM 薄膜的数量随沉积层数的增加而增加，这意味着姜黄素分配到薄膜的主体中。通过将不同厚度的薄膜暴露于高浓度（0.01%w/v）的姜黄素中并记录饱和后的最大吸光度来测量 PEM 薄膜中的最大姜黄素剂量。薄膜厚度通过沉积 PDADMAC/PSS 层的数量（10、20、30、40、50 和 60）来控制。结果表明，随着层数的增加，可以向薄膜中加载更多量的姜黄素，并且可以向 20 层薄膜中加载 8μg/cm(2)的姜黄素。这些结果表明，亲脂性姜黄素在 PEM 薄膜中的负载是通过分配机制完成的，并且 PDADMAC/PSS 薄膜可用作亲脂性药物的负载基质。
