Preparation and Characterization of Coenzyme Q₁₀–Eudragit® Solid Dispersion

ABSTRACT

A solid dispersion of Coenzyme Q₁₀ and Eudragit L 100-55 was prepared using solvent evaporation method. Solid dispersion, physical mixture, and pure compound were then characterized using differential scanning calorimetry and powder x-ray diffraction. Solubility of CoQ₁₀ in different surfactant media was measured, and a suitable dissolution medium was developed to compare the dissolution patterns of the solid dispersion, physical mixture, and the pure compound. Combining labrasol with different surfactants in dissolution media demonstrated an additive effect on CoQ₁₀ solubility. The solubility of CoQ₁₀ in a 4% Labrasol/2% Cremophor EL solution was 562 µg/ml, which was five times higher than the combined solubility in 5% Labrasol (91 µg/ml) and 5% Cremophor EL (7.8 µg/ml). Moderate change in the crystalline pattern of CoQ₁₀ was observed, which was attributed to solvent displacement rather than the degree of crystallinity change. The dissolution test indicated that the in-vitro release of Coenzyme Q₁₀ from its solid dispersion was much faster than its physical mixture, which in turn was faster than the pure drug. The amount of drug released in 12 hours from solid dispersion, physical mixture, and the pure drug was 100, 26.5 and 12.5% respectively. CoQ₁₀ was photostable throughout the dissolution experiments.