Stable packaging of retinol (Vitamin A) is important for food and cosmetic applications. Topical application of retinoids has been shown to help with skin conditions such as acne while also promoting collagen growth and regulating sebum. However, retinol degrades over time from light and oxygen exposure which causes irritation to the skin and ineffective results. A variety of encapsulation techniques have been proposed to stabilize retinol, but most of these continue to use preservatives such as butylated hydroxytoluene (BHT), which raise safety concerns. Our goal was to create a BHT-free liposomal retinol stable at room temperature for weeks to months. Retinol was embedded in a protective fatty bilayer made of phosphatidylcholine (PC) and a plant based fat-soluble antioxidant mix. Lipid vesicles were made by mixing PC, with or without the antioxidant blend, with organic solvent followed by isolation using rotary evaporation. Vesicles were characterized by confocal microscopy and fluorescence lifetime microscopy (FLIM) using the native fluorescence of retinol, sometimes accompanied by additional labels (rhodamine-PC, FM 1-43, or di-4-ANEPPS). The increased fluorescence quantum yield and lifetime of retinol in vesicles compared to solution was readily observed, and multilamellar vesicles were compared with unilamellar vesicles. Stability of the retinol in the liposomes was evaluated by fluorescence emission spectroscopy. Embedding the retinol in PC, without additional antioxidants, protected the molecule from oxidation for two weeks. Retinol in multilamellar vesicles showed greater stability than when embedded in unilamellar vesicles. Stability was increased to months when the antioxidant mix was added. These results suggest that BHT-free therapeutic creams could be produced to combat common skin ailments.

Stability of trans-retinol embedded in phosphatidylcholine multilayer vesicles

2019 Spring National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.