Establishment of a propolis ethanolic extract self-microemulsifying drug delivery system and its antibacterial activity

Abstract

Propolis is a natural product which has antioxidant, antibacterial and antitumor bioactivity, but the hard-dispersible characteristic limit its utilization. In this work, a propolis ethanolic extract (PEE) self-microemulsifying drug delivery system (SMEDDS) was developed for oral ingestion to improve its bioavailability. The best SMEDDS formula was selected by the solubility test, and the optimal prescription for the PEE-SMEDDS was obtained by the ternary phase diagram and pseudo-ternary phase diagram. The best SMEDDS formula was corn oil (as the oil phase), Tween 80 (as the surfactant), isopentyl alcohol (as the co-surfactant). The optimal prescription for the PEE-SMEDDS was corn oil and mixed surfactant (Tween 80: isopentyl alcohol with 9:1) which accounted for 14% and 86% respectively, with an added isoamyl alcohol (about 1/9 Tween 80 amount). The content of PEE in the drug-loaded SMEDDS was more than 15.0 mg PEE/100 mg SMEDDS, and the drug-loaded SMEDDS exhibited good stability within three months. The PEE-SMEDDS exhibited effective antibacterial activity against fungus, gram-positive bacteria, and gram-negative bacteria by the inhibition zone method. The outputs of this research will be helpful to the nutrition industry in the production of high nutrient-dense propolis with a self-microemulsifying drug delivery system.