Optimization of a Self-microemulsifying Drug Delivery System for Oral Administration of the Lipophilic Drug, Resveratrol: Enhanced Intestinal Permeability in Rat

This study aimed to formulate resveratrol, a practically water-insoluble antioxidant, in a self-microemulsifying drug delivery system (SMEDDS) to improve the solubility, release rate, and intestinal permeability of the drug.

The suitable oil, surfactant, and co-surfactant were chosen according to the drug solubility study. Utilizing the design of experiment (DoE) method, the pseudo-ternary phase diagram was plotted based on the droplet size. In vitro dissolution study and the single-pass intestinal perfusion (SPIP) were performed for the investigation of in vitro and in-situ permeability for drugs formulated as SMEDDS in rat intestine using high-performance liquid chromatography (HPLC).

Castor oil, Cremophor® RH60, and PEG 1500 were selected as oil, surfactant, and co-surfactant. According to the pseudo-ternary phase diagram, nine formulations developed microemulsions with sizes ranging between 145-967 nm. Formulations passed the centrifuge and freeze-thaw stability tests. The optimum formulation possessed an almost 2.5-fold higher cumulative percentage of in vitro released resveratrol, in comparison to resveratrol aqueous suspension within 120 minutes. The results of the in-situ permeability study suggested a 2.6-fold higher intestinal permeability for optimum formulation than that of the resveratrol suspension.

SMEDDS can be considered suitable for the oral delivery of resveratrol according to the observed increased intestinal permeability, which could consequently enhance the bioavailability and therapeutic efficacy of the drug.