Optimized self-microemulsifying drug delivery system improves the oral bioavailability and brain delivery of coenzyme Q10.

Our study aimed to develop a self-microemulsifying drug delivery system for the poorly aqueous-soluble drug Coenzyme Q₁₀, to improve the dissolution and the oral bioavailability. Excipients were selected based on their Coenzyme Q₁₀ solubility, and their concentrations were set for the optimization of the microemulsion by using a D-optimal mixture design to achieve a minimum droplet size and a maximum solubility of Coenzyme Q₁₀ within 15 min. The optimized formulation was composed of an oil (omega-3; 38.55%), a co-surfactant (Lauroglycol® 90; 31.42%), and a surfactant (Gelucire^® 44/14; 30%) and exhibited a mean droplet size of 237.6 ± 5.8 nm and a drug solubilization (at 15 min) of 16 ± 2.48%. The drug dissolution of the optimized formulation conducted over 8 h in phosphate buffer medium (pH 6.8) was significantly higher when compared to that of the Coenzyme Q₁₀ suspension. A pharmacokinetic study in rats revealed a 4.5-fold and a 4.1-fold increase in the area under curve and the peak plasma concentration values generated by the optimized formulation respectively, as compared to the Coenzyme Q₁₀ suspension. A Coenzyme Q₁₀ brain distribution study revealed a higher Coenzyme Q₁₀ distribution in the brains of rats treated with the optimized formulation than the Coenzyme Q₁₀ suspension. Coenzyme Q₁₀-loaded self microemulsifying drug delivery system was successfully formulated and optimized by a response surface methodology based on a D-optimal mixture design and could be used as a delivery vehicle for the enhancement of the oral bioavailability and brain distribution of poorly soluble drugs such as Coenzyme Q₁₀.