Purpose

Design imiquimod-loaded chitosan nanocapsules for transdermal delivery and evaluate the depth of imiquimod transdermal absorption as well as the kinetics of this absorption using Raman Microscopy, an innovative strategy to evaluate transdermal absorption. This nanovehicle included Compritol 888ATO®, a novel excipient for formulating nanosystems whose administration through the skin has not been studied until now.

Methods

Nanocapsules were made by solvent displacement method and their physicochemical properties was measured by DLS and laser-Doppler. For transdermal experiments, newborn pig skin was used. The Raman spectra were obtained using a laser excitation source at 532 nm and a 20/50X oil immersion objective.

Results

The designed nanocapsules, presented nanometric size (180 nm), a polydispersity index <0.2 and a zeta potential +17. The controlled release effect of Compritol was observed, with the finding that half of the drug was released at 24 h in comparison with control (p < 0.05). It was verified through Raman microscopy that imiquimod transdermal penetration is dynamic, the nanocapsules take around 50 min to penetrate the stratum corneum and 24 h after transdermal administration, the drug was in the inner layers of the skin.

Conclusions

This study demonstrated the utility of Raman Microscopy to evaluate the drugs transdermal penetration of in the different layers of the skin.

中文翻译：

---

用于咪喹莫特透皮给药的Compritol 888ATO®壳聚糖纳米胶囊的设计。通过拉曼显微镜评估它们的皮肤吸收。

目的

使用拉曼显微镜（一种用于评估透皮吸收的创新策略），设计用于透皮递送的载有咪喹莫特的壳聚糖纳米胶囊，并评估咪喹莫特透皮吸收的深度以及这种吸收的动力学。该纳米载体包括Compritol888ATO®，这是一种用于配制纳米系统的新型赋形剂，其迄今为止尚未通过皮肤进行研究。

方法

采用溶剂置换法制备了纳米胶囊，并用DLS和激光多普勒法对其理化性质进行了测定。对于透皮实验，使用新生猪皮。拉曼光谱是使用532 nm的激光激发源和20 / 50X油浸物镜获得的。

结果

设计的纳米胶囊呈现纳米尺寸（180 nm），多分散指数<0.2，ζ电位+17。观察到Compritol的控制释放效果，发现与对照组相比，该药物在24 h释放了一半（p  <0.05）。通过拉曼显微镜证实，咪喹莫特透皮渗透是动态的，纳米胶囊大约需要50分钟才能穿透角质层，而经皮给药后24小时，该药物位于皮肤的内层。

结论

这项研究证明了拉曼显微镜用于评估药物在皮肤不同层中的透皮渗透性。