Preparation and characterization of nanoparticles from microemulsion system for topical delivery of Coenzyme Q10

Abstract

Nanoparticles have been prepared by simple cooling of a warm microemulsion template. In this study, the microemulsion was achieved by varying the oil phase (emulsifying wax or Brij® 72) and surfactant phase (Brij® 78 or Tween® 80). It was found that the type of lipid matrix and concentration of surfactant had an effect on the size of the nanoparticles. The rapid cooling of a warm microemulsion in an ice-bath caused the precipitation of the lipid phase to form the smaller nanoparticles. The systems composed of emulsifying wax (cetostearyl alcohol and cetomacrogol) and Tween® 80 offered the small, uniform and stable nanoparticles. Coenzyme Qio was then incorporated into the nanoparticles and it was shown that the concentration of wax and Tween® 80 had influence on the size of Coenzyme Qio- loaded nanoparticles. The formulation which was selected to incorporate Coenzyme Qio was composed of 4 mg/mL wax and 48 mM Tween® 80. The Coenzyme Qio-loaded nanoparticles were spherical and had the size smaller than 100 nm and high percentage entrapment efficiency; 80.19% and 78.00 % for 2 and 4 mg/mL Coenzyme Qio, respectively. The differential scanning calorimetry analysis indicated that Coenzyme Qio was dispersed in lipid matrix as an amorphous state and the Coenzyme Qio-loaded nanoparticles were not a simple physical mixture of their individual component. The in vitro release profile of Coenzyme Qio from nanoparticles exhibited a rapidly initial release in the first ten hours, followed by a period of slower and extened release. Freeze-dried Coenzyme Qio-loaded nanoparticles using 2% w/w mannitol as a cryoprotectant showed a greater stability than non freeze-dried nanoparticles. Moreover the cream mixed with Coenzyme Qio-loaded nanoparticles offered a good physical stability under accelerated condition. In conclusion, Coenzyme Qio-loaded nanoparticles were prepared from microemulsion template and could be incorporated in to topical preparation.