Abstract

Oil-in-water microemulsions (o/w MEs) were coated with chitosan to obtain new curcumin delivery systems. First, ternary phase diagrams were constructed using mixtures of Tween 20, Tween 80, ethanol, and monopropyleneglycol (MPG) to determine the macroscopic phase region of MEs and their capacity to incorporate clove oil. Particularly, MEs with size less than 20 nm could be formed using low amount of the surfactant Tween 20. The prepared MEs were subjected to diverse stability tests and characterized by dynamic light scattering (DLS), zeta potential (Z potential), conductivity, pH, and transmission electron microscopy (TEM). Stable, spherical uncoated and polymer-coated MEs were obtained with low droplet size (Dp), <50 nm, for the water/Tween 20/clove oil/ and water/Tween80/MPG/clove oil systems using a chitosan solution of 1 mg/mL. For all polymer-coated MEs, an increase of Z potential (17–54 mV) was observed due to the presence of chitosan. The loading with curcumin did not affect the Dp of MEs (e.g., for ME with Tween 20, Dp unloaded 12.35 ± 1.86 nm and Dp loaded 11.13 ± 0.32 nm) but Z potential and conductivity values were increased (typically for coated ME prepared with Tween 20 17.00 ± 0.36 mV ≤Z potential ≤41.5 mV, 162.20 ± 8.95 μS/cm ≤ conductivity ≤183.8 ± 0.56 μS/cm). Drug delivery studies for the chitosan-coated MEs were carried out at different pH (7.4, 6.5, and 5.8). The release of curcumin from the chitosan-coated MEs, formed with Tween 20, showed a dependence of the pH with a maximum release at the acidic pH of 5.8 (58%). The release of curcumin from all MEs was best described by the Korsmeyer- Peppas model with a Fickian transport mechanism.

摘要

用壳聚糖包衣水包油微乳液（o / w MEs）以获得新的姜黄素递送系统。首先，使用吐温20，吐温80，乙醇和单丙二醇（MPG）的混合物构建三元相图，以确定ME的宏观相区域及其掺入丁香油的能力。特别地，可以使用少量的表面活性剂吐温20来形成尺寸小于20nm的ME。所制备的ME经过各种稳定性测试，并以动态光散射（DLS），ζ电势（Z电势），电导率，pH为特征。 ，以及透射电子显微镜（TEM）。获得了稳定的，球形的，未涂覆的和涂覆了聚合物的ME，液滴尺寸较低（Dp对于水/吐温20 /丁香油/和水/吐温80 / MPG /丁香油系统，使用1 mg / mL的壳聚糖溶液，<50 nm。对于所有聚合物包被的ME，由于存在壳聚糖，导致Z电位增加（17-54 mV）。姜黄素的负载量不会影响ME的Dp（例如，对于Tween 20的ME，Dp的负载量为12.35±1.86 nm，Dp的负载量为11.13±0.32 nm），但Z电位和电导率值均增加了（通常对于涂有Tween的包被的ME 20 17.00±0.36毫伏≤ ž电势≤41.5mV，162.20±8.95μS/ cm≤电导率≤183.8±0.56μS/ cm）。在不同的pH值（7.4、6.5和5.8）下进行了壳聚糖包被的MEs的药物递送研究。由吐温20形成的壳聚糖包衣的MEs中姜黄素的释放表现出对pH的依赖性，在酸性pH为5.8时最大释放（58％）。姜黄素从所有MEs中的释放最好通过具有Fickian转运机制的Korsmeyer-Peppas模型来描述。