Oil-enriched, ultra-small nanostructured lipid carriers (usNLC): A novel delivery system based on flip–flop structure

Abstract

For the development of ultra-small NLC (usNLC) the determination of the required HLB (hydrophilic lipophilic balance) was found to be a suitable method, i.e., usNLC with a size below 50nm were obtained by this method. Loading with 5% (w/w) coenzyme Q10 (Q10) led to usNLC with a size of about 85nm. In comparison to classical NLC with a size of 230nm and a nanoemulsion with similar size, the Q10 loaded usNLC show a higher release, a higher antioxidant capacity, and a better skin penetration for Q10. The reason for this is a flip–flop core–shell structure of the lipid matrix, i.e., the oil with dissolved active is surrounding the solid lipid based core. As the flip–flop structure was probably achieved by admixing high contents of liquid lipid, oil enriched usNLC might represent a novel and promising carrier system for the improved delivery of lipophilic actives.