Tabriz University of Medical Sciences Advanced Pharmaceutical Bulletin 2228-5881 13 3 2023 07 10 Optimization of a Self-microemulsifying Drug Delivery System for Oral Administration of the Lipophilic Drug, Resveratrol: Enhanced Intestinal Permeability in Rat 521 531 10.34172/apb.2023.054 EN Shahla Mirzaeei https://orcid.org/0000-0002-1132-3150 Negar Tahmasebi https://orcid.org/0000-0001-6396-1456 Ziba Islambulchilar https://orcid.org/0000-0001-7037-4436 Journal Article 10.34172/apb.2023.054 2021 10 04 2022 07 01 Purpose: 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. Methods: 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 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. Results: 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. Conclusions: 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.