A comparative study of lipid-based drug delivery systems with different microstructure for combined dermal administration of antioxidant vitamins

Abstract

Antioxidant vitamins have been proven to be highly efficient in treatment of skin impaired by oxidative stress, but challenges regarding stability and skin penetration limit their therapeutic effect. Lipid-based drug delivery systems offer great potential for overcoming these drawbacks. This work aimed to identify the most promising system for combined antioxidant therapy. A comparative assessment of several systems, containing the same ingredients but differing in their microstructure, was therefore performed. Namely, microemulsions (MEs) of both types (W/O and O/W) and lyotropic liquid crystals (LLCs), simultaneously loaded with vitamin C or ascorbyl palmitate and vitamin E, were assessed. Stability, antioxidant capacity (DPPH assay), and release (Franz diffusion cells) of the vitamins incorporated was examined. The results obtained were supported with the systems’ thermal and rheological (rotational and oscillatory tests) evaluation. In addition, biological acceptability (MTS assay) of the systems studied was investigated. The findings demonstrate that the microstructure of MEs and LLCs studied has a decisive impact on the stability, antioxidant activity, and release of the vitamins incorporated. The highest stability was preserved in LLCs for both pairings, with vitamins C and E being a more stable combination. LLCs also provided suitable vitamins’ antioxidant activity and release characteristics. In addition, the system exhibited preferable rheological features for dermal administration. Furthermore, cytotoxicity studies on a keratinocyte cell line demonstrated the highest biocompatibility for LCCs with the cell proliferation being greater than 85%. In conclusion, LLCs were confirmed as the most favorable lipid-based drug delivery system for combined antioxidant treatment.