Preparation of Coenzyme Q10 nanostructured lipid carriers for epidermal targeting with high-pressure microfluidics technique

Objective: The objective of this work was to prepare coenzyme Q10 loaded nanostructured lipid carriers (Q10-NLC) and evaluate its epidermal targeting effect. Methods: Q10-NLC was prepared by high-pressure microfluidics technique. Formulations and preparation parameters were optimized with response surface design. Q10-NLC was characterized by PCS, TEM, DSC and PXRD. The penetration of Q10 from the Q10-NLC formulations through skins and into skins were evaluated in vitro using Franz diffusion cells fitted with SD rat skins. In vitro release, long-term stability and light stability were also evaluated. Results: The results showed that the concentration of solid lipid and emulsifier in formulation had a significant influence on particle size. The optimized preparation parameters were magnetic stirring for 20 min, high stirring at 8000 rpm for 1 min and high-pressure microfluidics at 1200 bar for three cycles. The size of Q10-NLC prepared by optimized formulation and parameters was (151.7 +/- 2.31) nm, polydispersity (PDI) 0.144, zeta potential was (-44.1 +/- 1.68) mV, drug loading 2.51%, encapsulation efficiency 100%. In vitro release study, Q10-NLC showed fast release during the first 3 hours and prolonged release afterwards. In vitro skin permeation study, the accumulative uptake of Q10 in epidermal of Q10-NLC was 10.11 times over Q10 emulsion. After exposure to day light for 24 hours, the amount of Q10 in Q10-NLC decreased only 5.59%, while in Q10 emulsion decreased 24.61% and Q10-ethanol solution 49.74%. Conclusion: Q10-NLC exhibited a significant epidermal targeting effect, which was proved to be a promising carrier for topical delivery of Q10.