The present investigation describes a formulative study aimed at designing ethosomes for caffeic acid transdermal administration. Since caffeic acid is characterized by antioxidant potential but also high instability, its encapsulation appears to be an interesting strategy. Ethosomes were produced by adding water into a phosphatidylcholine ethanol solution under magnetic stirring. Size distribution and morphology of ethosome were investigated by photon correlation spectroscopy, small-angle X-ray spectroscopy, and cryogenic transmission electron microscopy, while the entrapment capacity of caffeic acid was evaluated by high-performance liquid chromatography. Caffeic acid stability in ethosome was compared to the stability of the molecule in water, determined by mass spectrometry. Ethosome dispersion was thickened by poloxamer 407, obtaining an ethosomal gel that was characterized for rheological behavior and deformability. Caffeic acid diffusion kinetics were determined by Franz cells, while its penetration through skin, as well as its antioxidant activity, were evaluated using a porcine skin membrane–covered biosensor based on oxygen electrode. Ethosome mean diameter was ≈200 nm and almost stable within three months. The entrapment of caffeic acid in ethosome dramatically prolonged drug stability with respect to the aqueous solution, being 77% w/w in ethosome after six months, while in water, an almost complete degradation occurred within one month. The addition of poloxamer slightly modified vesicle structure and size, while it decreased the vesicle deformability. Caffeic acid diffusion coefficients from ethosome and ethosome gel were, respectively, 137- and 33-fold lower with respect to the aqueous solution. At last, the caffeic acid permeation and antioxidant power of ethosome were more intense with respect to the simple solution.

中文翻译：

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设计和表征用于咖啡酸透皮递送的脂质体。

本研究描述了旨在设计用于咖啡酸透皮给药的核糖体的配方研究。由于咖啡酸的特点是具有抗氧化剂的潜力，但同时也具有很高的不稳定性，因此将其封装似乎是一种有趣的策略。通过在磁力搅拌下将水添加到磷脂酰胆碱乙醇溶液中来产生脂质体。通过光子相关光谱，小角度X射线光谱和低温透射电子显微镜研究了核糖体的大小分布和形态，同时用高效液相色谱法评估了咖啡酸的包封能力。通过质谱法将咖啡因中的咖啡酸稳定性与分子在水中的稳定性进行了比较。泊洛沙姆407使埃索体分散液增稠，获得具有流变行为和可变形性特征的内体凝胶。咖啡酸的扩散动力学由Franz细胞决定，而咖啡酸通过皮肤的渗透及其抗氧化活性则使用基于氧气电极的猪皮肤膜覆盖生物传感器进行评估。核小体平均直径约为200 nm，在三个月内几乎稳定。相对于水溶液，咖啡因截留在核糖体中的稳定性显着延长，为77％体平均直径约为200 nm，并且在三个月内几乎保持稳定。相对于水溶液，咖啡因截留在核糖体中的稳定性显着延长，为77％体平均直径约为200 nm，并且在三个月内几乎保持稳定。相对于水溶液，咖啡因截留在核糖体中的稳定性显着延长，为77％w / w在六个月后的水质中，而在水中，一个月内几乎完全降解。泊洛沙姆的加入稍微改变了囊泡的结构和大小，同时降低了囊泡的可变形性。相对于水溶液，来自乙醇体和乙醇体凝胶的咖啡酸扩散系数分别降低了137倍和33倍。最后，相对于简单溶液，咖啡因的渗透性和氧化酶的抗氧化能力更为强烈。