Formulation of a stable and high-loaded quercetin injectable emulsion

The purpose of this paper was to prepare a stable and high-loaded quercetin emulsion with the quercetin-phospholipid complex. The complex was analyzed by FT-IR and SEM. Quercetin and soybean lecithin were reacted in dichloromethane at a ratio of 1:2.5 for 2 h at 40°C to prepare the complex. The optimum quercetin emulsion formulation consisted of (according to quality percentage), the complex (quercetin 0.06% in the emulsion), miglyol 812 10%, soybean oil 2%, solutol HS 15 1.2%, cremophor ELP 0.4%, vitamin E 0.2%, oleic acid 0.5%, glycerol 2.5%. The quercetin emulsion was sterilized at 121°C for 15 min. The drug content and particle size distribution of the emulsion before and after sterilization were almost unchanged. The results of accelerate stability (stored at 40°C over one month) and short-time stability (stored at room temperature over six months) tests showed that the quercetin emulsion had enough physicochemical stability to undergo storage. The histopathological examination for rabbit ear vein irritation test indicated that the quercetin emulsion produced no more irritation than normal saline.