Self-Microemulsifying Drug Delivery System of Phillygenin: Formulation Development, Characterization and Pharmacokinetic Evaluation

Phillygenin inhibits neuroinflammation and promotes functional recovery after spinal cord injury via TLR4 inhibition of the NF-κB signaling pathway

Background

Spinal cord injuries (SCIs) trigger a cascade of detrimental processes, encompassing neuroinflammation and oxidative stress (OS), ultimately leading to neuronal damage. Phillygenin (PHI), isolated from forsythia, is used in a number of biomedical applications, and is known to exhibit anti-neuroinflammation activity. In this study, we investigated the role and mechanistic ability of PHI in the activation of microglia-mediated neuroinflammation and subsequent neuronal apoptosis following SCI.

Methods

A rat model of SCI was used to investigate the impact of PHI on inflammation, axonal regeneration, neuronal apoptosis, and the restoration of motor function. In vitro, neuroinflammation models were induced by stimulating microglia with lipopolysaccharide (LPS); then, we investigated the influence of PHI on pro-inflammatory mediator release in LPS-treated microglia along with the underlying mechanisms. Finally, we established a co-culture system, featuring microglia and VSC 4.1 cells, to investigate the role of PHI in the activation of microglia-mediated neuronal apoptosis.

Results

In vivo, PHI significantly inhibited the inflammatory response and neuronal apoptosis while enhancing axonal regeneration and improving motor function recovery. In vitro, PHI inhibited the release of inflammation-related factors from polarized BV2 cells in a dose-dependent manner. The online Swiss Target Prediction database predicted that toll-like receptor 4 (TLR4) was the target protein for PHI. In addition, Molecular Operating Environment software was used to perform molecular docking for PHI with the TLR4 protein; this resulted in a binding energy interaction of -6.7 kcal/mol. PHI inhibited microglia-mediated neuroinflammation, the production of reactive oxygen species (ROS), and activity of the NF-κb signaling pathway. PHI also increased mitochondrial membrane potential (MMP) in VSC 4.1 neuronal cells. In BV2 cells, PHI attenuated the overexpression of TLR4-induced microglial polarization and significantly suppressed the release of inflammatory cytokines.

Conclusion

PHI ameliorated SCI-induced neuroinflammation by modulating the TLR4/MYD88/NF-κB signaling pathway. PHI has the potential to be administered as a treatment for SCI and represents a novel candidate drug for addressing neuroinflammation mediated by microglial cells.

The translational potential of this article

We demonstrated that PHI is a potential drug candidate for the therapeutic management of SCI with promising developmental and translational applications.

The phytochemistry, pharmacology, pharmacokinetics, quality control, and toxicity of Forsythiae Fructus: An updated systematic review

Forsythiae Fructus (FF), the dried fruit of F. suspensa, is commonly used to treat fever, inflammation, etc in China or other Asian countries. FF is usually used as the core herb in traditional Chinese medicine preparations for the treatment of influenza, such as Shuang-huang-lian oral liquid and Yin-qiao powder, etc. Since the wide application and core role of FF, its research progress was summarized in terms of traditional uses, phytochemistry, pharmacology, pharmacokinetics, quality control, and toxicity. Meanwhile, the anti-influenza substances and mechanism of FF were emphasized. Till now, a total of 290 chemical components are identified in F. suspensa, and among them, 248 components were isolated and identified from FF, including 42 phenylethanoid glycosides, 48 lignans, 59 terpenoids, 14 flavonoids, 3 steroids, 24 cyclohexyl ethanol derivatives, 14 alkaloids, 26 organic acids, and 18 other types. FF and their pure compounds have the pharmacological activities of anti-virus, anti-inflammation, anti-oxidant, anti-bacteria, anti-tumor, neuroprotection, hepatoprotection, etc. Inhibition of TLR7, RIG-I, MAVS, NF-κB, MyD88 signaling pathway were the reported anti-influenza mechanisms of FF and phenylethanoid glycosides and lignans are the main active groups. However, the bioavailability of phenylethanoid glycosides and lignans of FF in vivo was low, which needed to be improved. Simultaneously, the un-elucidated compounds and anti-influenza substances of FF strongly needed to be explored. The current quality control of FF was only about forsythoside A and phillyrin, more active components should be taken into consideration. Moreover, there are no reports of toxicity of FF yet, but the toxicity of FF should be not neglected in clinical applications.

Simplex Lattice Design and Machine Learning Methods for the Optimization of Novel Microemulsion Systems to Enhance p-Coumaric Acid Oral Bioavailability: In Vitro and In Vivo Studies

Novel p-coumaric acid microemulsion systems were developed to circumvent its absorption and bioavailability challenges. Simplex-lattice mixture design and machine learning methods were employed for optimization. Two optimized formulations were characterized using in vitro re-dispersibility and cytotoxicity on various tumor cell lines (MCF-7, CaCO2, and HepG2). The in vivo bioavailability profiles of the drug loaded in the two microemulsion systems and in the suspension form were compared. The optimized microemulsions composed of Labrafil M1944 CS (5.67%)/Tween 80 (38.71%)/Labrasol (38.71%)/water (16.92%) and Capryol 90 (0.50%)/Transcutol P (26.67%)/Tween 80 (26.67%)/Labrasol (26.67%)/water (19.50%), respectively. They revealed uniform and stable p-coumaric acid-loaded microemulsion systems with a droplet size diameter of about 10 nm. The loaded microemulsion formulations enhanced the drug re-dispersibility in contrast to the drug suspension which exhibited 5 min lag time. The loaded formulae were significantly more cytotoxic on all cell lines by 11.98-16.56 folds on MCF-7 and CaCo2 cells and 47.82-98.79 folds on HepG2 cells higher than the pure drug. The optimized microemulsions were 1.5-1.8 times more bioavailable than the drug suspension. The developed p-coumaric acid microemulsion systems could be considered a successful remedy for diverse types of cancer.

Preparation of Phillygenin-Hyaluronic acid composite milk-derived exosomes and its anti-hepatic fibrosis effect

Liver fibrosis remains a serious problem affecting the health of millions of people worldwide. Hepatic stellate cells (HSCs) are the main effector cells in liver fibrosis and their activation could lead to extracellular matrix deposition, which may aggravate the development of liver fibrosis and inflammation. Previous studies have reported the potential of Phillygenin (PHI) as a hepatoprotective agent to inhibit HSCs activation and fibrosis development. However, the poor water solubility of PHI hinders its clinical application as a potential anti-liver fibrosis therapy. Milk-derived exosomes (mEXO) serve as scalable nanocarriers for delivering chemotherapeutic agents due to their excellent biocompatibility. Here, we developed a PHI-Hyaluronic acid (HA) composite mEXO (PHI-HA-mEXO) drug delivery system, in which DSPE-PEG2000-HA was conjugated to the surface of mEXO to prepare HA-mEXO, and PHI was encapsulated into HA-mEXO to form PHI-HA-mEXO. As a specific receptor for HA, CD44 is frequently over-expressed during liver fibrosis and highly expressed on the surface of activated HSCs (aHSCs). PHI-HA-mEXO can bind to CD44 and enter aHSCs through endocytosis and release PHI. PHI-HA-mEXO drug delivery system can significantly induce aHSCs death without affecting quiescent HSCs (qHSCs) and hepatocytes. Furthermore, we carried out in vitro and in vivo experiments and found that PHI-HA-mEXO could alleviate liver fibrosis through aHSCs-targeted mechanism. In conclusion, the favorable biosafety and superior anti-hepatic fibrosis effects suggest a promising potential of PHI-HA-mEXO in the treatment of hepatic fibrosis. However, detailed pharmokinetics and dose-responsive experiments of PHI-HA-mEXO and the mechanism of mEXO loading drugs are still required before PHI-HA-mEXO can be applied clinically.

A comprehensive review on pharmacological, toxicity, and pharmacokinetic properties of phillygenin: Current landscape and future perspectives

Forsythiae Fructus is a traditional Chinese medicine frequently in clinics. It is extensive in the treatment of various inflammation-related diseases and is renowned as 'the holy medicine of sores'. Phillygenin (C21H24O6, PHI) is a component of lignan that has been extracted from Forsythiae Fructus and exhibits notable biological activity. Modern pharmacological studies have confirmed that PHI demonstrates significant activities in the treatment of various diseases, including inflammatory diseases, liver diseases, cancer, bacterial infection and virus infection. Therefore, this review comprehensively summarizes the pharmacological effects of PHI up to June 2023 by searching PubMed, Web of Science, Science Direct, CNKI, and SciFinder databases. According to the data, PHI shows remarkable anti-inflammatory, antioxidant, hepatoprotective, antitumour, antibacterial, antiviral, immunoregulatory, analgesic, antihypertensive and vasodilatory activities. More importantly, NF-κB, MAPK, PI3K/AKT, P2X7R/NLRP3, Nrf2-ARE, JAK/STAT, Ca2+-calcineurin-TFEB, TGF-β/Smads, Notch1 and AMPK/ERK/NF-κB signaling pathways are considered as important molecular targets for PHI to exert these pharmacological activities. Studies of its toxicity and pharmacokinetic properties have shown that PHI has very low toxicity, incomplete absorption in vivo and low oral bioavailability. In addition, the physico-chemical properties, new formulations, derivatives and existing challenges and prospects of PHI are also reviewed and discussed in this paper, aiming to provide direction and rationale for the further development and clinical application of PHI.

Development of Osthole-Loaded Microemulsions as a Prospective Ocular Delivery System for the Treatment of Corneal Neovascularization: In Vitro and In Vivo Assessments

Osthole (OST), a natural coumarin compound, has shown a significant inhibitory effect on corneal neovascularization (CNV). But, its effect on treating CNV is restricted by its water insolubility. To overcome this limitation, an OST-loaded microemulsion (OST-ME) was created to improve the drug's therapeutic effect on CNV after topical administration. The OST-ME formulation comprised Capryol-90 (CP-90), Cremophor® EL (EL-35), Transcutol-P (TSP) and water, and sodium hyaluronate (SH) was also included to increase viscosity. The OST-ME had a droplet size of 16.18 ± 0.02 nm and a low polydispersity index (0.09 ± 0.00). In vitro drug release from OST-ME fitted well to the Higuchi release kinetics model. Cytotoxicity assays demonstrated that OST-ME was not notably toxic to human corneal epithelial cells (HCECs), and the formulation had no irritation to rabbit eyes. Ocular pharmacokinetics studies showed that the areas under the concentration-time curves (AUC0-t) in the cornea and conjunctiva were 19.74 and 63.96 μg/g*min after the administration of OST-ME, both of which were 28.2- and 102.34-fold higher than those after the administration of OST suspension (OST-Susp). Moreover, OST-ME (0.1%) presented a similar therapeutic effect to commercially available dexamethasone eye drops (0.025%) on CNV in mouse models. In conclusion, the optimized OST-ME exhibited good tolerance and enhanced 28.2- and 102.34-fold bioavailability in the cornea and conjunctiva tissues compared with suspensions in rabbit eyes. The OST-ME is a potential ocular drug delivery for anti-CNV.

Formulation and in vitro evaluation of meloxicam as a self-microemulsifying drug delivery system

Background: The nonsteroidal anti-inflammatory medication meloxicam (MLX) belongs to the oxicam family and is used to reduce inflammation and pain. The aim of this study was to improve MLX's dispersibility and stability by producing it as a liquid self-microemulsifying drug delivery system since it is practically insoluble in water. Methods: Five different formulations were made by adjusting the amounts of propylene glycol, Transcutol P, Tween 80, and oleic acid oil and establishing a pseudo-ternary diagram in ratios of 1:1, 1:2, 1:3, 1:4, and 3:4, respectively. All of the prepared formulations were tested for a variety of properties, including thermodynamic stability, polydispersity index, particle size distributions, dilution resistance, drug contents, dispersibility, in vitro solubility of the drug, and emulsification time. Results: F5 was chosen as the optimal MLX liquid self-microemulsion due to its higher drug content (99.8%), greater in vitro release (100% at 40 min), smaller droplet size (63 nm), lower polydispersity index (PDI) value (0.3), and higher stability (a zeta potential of -81 mV). Conclusions: According to the data provided here, the self-microemulsifying drug delivery system is the most practical method for improving the dispersibility and stability of MLX.

Application of Design of Experiments in the Development of Self-Microemulsifying Drug Delivery Systems

Oral delivery has become the route of choice among all other types of drug administrations. However, typical chronic disease drugs are often poorly water-soluble, have low dissolution rates, and undergo first-pass metabolism, ultimately leading to low bioavailability and lack of efficacy. The lipid-based formulation offers tremendous benefits of using versatile excipients and has great compatibility with all types of dosage forms. Self-microemulsifying drug delivery system (SMEDDS) promotes drug self-emulsification in a combination of oil, surfactant, and co-surfactant, thereby facilitating better drug solubility and absorption. The feasible preparation of SMEDDS creates a promising strategy to improve the drawbacks of lipophilic drugs administered orally. Selecting a decent mixing among these components is, therefore, of importance for successful SMEDDS. Quality by Design (QbD) brings a systematic approach to drug development, and it offers promise to significantly improve the manufacturing quality performance of SMEDDS. Furthermore, it could be benefited efficiently by conducting pre-formulation studies integrated with the statistical design of experiment (DoE). In this review, we highlight the recent findings for the development of microemulsions and SMEDDS by using DoE methods to optimize the formulations for drugs in different excipients with controllable ratios. A brief overview of DoE concepts is discussed, along with its technical benefits in improving SMEDDS formulations.

Phillygenin from Forsythia suspensa leaves exhibits analgesic potential and anti-inflammatory activity in carrageenan-induced paw edema in mice

Forsythia suspensa (Thunb.) Vahl (Oleaceae) leaves are valuable sources of phillygenin. This study aimed to isolate phillygenin from F. suspensa leaves and examine its analgesic and anti-inflammatory effects. Phillygenin was successfully extracted and isolated from F. suspensa leaves after fermentation. Phillygenin significantly reduced the number of writhing induced by acetic acid, prolonged the latency period in the hot plate test, and inhibited the xylene-induced ear edema and carrageenan-induced paw edema in mice. IL-6, TNF-α, IL-1β, NO, and PGE₂ levels in the carrageenan-induced paw edema were notably reduced after pretreatment with phillygenin. Phillygenin significantly decreased the iNOS and COX-2 protein expressions and the IκB-α and NF-κB p65 phosphorylation. This study demonstrated that phillygenin is a potential therapeutic candidate for managing pain and inflammation-mediated disorders. The study contributes to the comprehensive development and utilization of F. suspensa leaves for economic and health care. PRACTICAL APPLICATIONS: Phillygenin is one of the major active ingredients in Forsythia suspensa. But the content of phillygenin in F. suspensa is very low which limits its application. Phillygenin has potential pharmacological activity and anti-inflammatory properties. However, the potential effects of phillygenin on analgesic activity have not been clarified. Furthermore, the data on its anti-inflammatory activity in vivo are relatively limited. This study evaluated the analgesic activity for the first time and the acute anti-inflammatory effect of phillygenin from F. suspensa leaves by fermentation, which indicated phillygenin is a potential therapeutic candidate for managing pain and inflammation-mediated disorders.

Preparation and evaluation of a lipid-based drug delivery system to ımprove valsartan oral bioavailability: pharmacokinetic and pharmacodynamic analysis

Antihypertensive treatment reduces the risk of cardiovascular complications in patients with high mortality with hypertension. Valsartan is highly selective antihypertensive that is rapidly absorbed after oral administration, but its oral bioavailability is only 25%. It is absorbed from the upper part of the gastrointestinal tract but is less soluble in this acidic environment. We aimed to develop a lipid-based formulation to produce a self-emulsifying drug delivery system (SEDDS) for valsartan. Solubility studies were performed to identify the components of the SEDDS that provided the best dissolution of valsartan. Ternary phase diagrams were drawn using the titration method with oil, surfactants and co-surfactants in which valsartan was highly soluble, and microemulsion formulations with the highest area were determined. Characterization and in vitro release studies were performed to optimize the formulation. In vitro release profiles of commercial and SEDDS formulations showed the F2 formulation release rate increased at pH 1.2 fasted state simulated gastric fluid. After oral administration, plasma drug concentrations in rats indicate that the F2 formulation provided a 4.2-fold greater AUC for valsartan than the commercial formulaiton, resulting in an 8.5-fold greater Cmax. These findings suggest the F2 formulation increases valsartan solubility, resulting in an improved oral pharmacokinetic profile. According to the pharmacodynamic study, the F2 formulation is more effective than the commercial formulation in restoring systolic and diastolic blood pressure within a few hours.

Production, physicochemical investigations, antioxidant effect, and cellular uptake in Caco-2 cells of the supersaturable astaxanthin self-microemulsifying tablets

The purpose of this study was to develop astaxanthin (AST)-loaded self-microemulsifying drug delivery system (SMEDDS) tablets and evaluate their physicochemical and biological properties. The optimized liquid (L)-AST SMEDDS formulation was composed of rice bran oil (33.67%), Kolliphor® RH 40 (34.70%), and Span® 20 (31.63%). Two types of hydrophilic polymers (hydroxypropyl methylcellulose, HPMC, and polyvinyl alcohol, PVA) solutions were selected as a precipitation inhibitor for AST and incorporated into L-AST SMEDDS to obtain supersaturation and enhance dissolution of AST. The formulation was then mixed with microcrystalline cellulose and subsequently transformed to solid S-AST SMEDDS particles using a spray dryer prior to direct compression into tablets. The HPMC AST SMEDDS tablet and PVA AST SMEDDS tablet were characterized for their physicochemical properties, dissolution, AST release, and stabilities. Moreover, the cellular uptake and antioxidant effect of AST SMEDDS tablets were evaluated in Caco-2 cells. With good tablet characters, both HPMC AST SMEDDS tablet and PVA AST SMEDDS tablet dissolution profiles were improved compared to that of raw AST. While initially less than 50% of AST released from HPMC AST SMEDDS tablet and PVA AST SMEDDS tablet in pH 1.2 medium, after 6 h more than 98% of AST releases in pH 6.8 were achieved which was similar to L-AST SMEDDS profile. Cellular antioxidant activities of L-AST SMEDDS and HPMC AST SMEDDS tablet & PVA AST SMEDDS tablet were significantly greater than pure AST powder. HPMC AST SMEDDS tablet showed better uptake and deeper penetration through Caco-2 cells than that in PVA AST SMEDDS tablet and pure powder. Our successfully developed AST SMEDDS tablets were demonstrated to be a potential platform to deliver highly lipophilic AST and improve permeation and bioavailability.

Dietary phillygenin supplementation ameliorates aflatoxin B1-induced oxidative stress, inflammation, and apoptosis in chicken liver

Aflatoxin B₁ (AFB₁), a mycotoxin contaminating food and feed, can trigger liver immune toxicity and threaten the poultry industry. Phillygenin (PHI) is a natural lignan derived primarily from Forsythia suspensa with hepatoprotective pharmacological and medicinal properties. This research aimed to investigate the preventive effects of PHI on the toxicity of AFB₁ in the liver of chickens. Chickens were administered with AFB₁ (2.8 mg/kg) and/or treated with PHI (24 mg/kg) for 33 days. The histopathological changes, serum biochemical indices, oxidative damage, inflammatory mediators, apoptosis, and activation of the NF-κB and Nrf2 signaling pathways were measured. Results revealed that dietary PHI ameliorated liver function indicators, reduced the malondialdehyde and inflammatory mediator production and the apoptotic cell number, and increased the antioxidant enzyme contents and Bcl-2 level. The quantitative realtime PCR and Western blot results revealed that PHI reduced p53, cytochrome c, Bax, caspase-9, and caspase-3 levels, normalized the NF-κB p65 phosphorylation, and upregulated the Nrf2 and its downstream genes expression in chicken liver. These results indicated that PHI has beneficial effects on AFB₁-induced liver damage, oxidative damage, inflammatory response, apoptosis, and immunotoxicity by inhibiting NF-κB and activating the Nrf2 signaling pathway in chickens. This study provides new insight into the therapeutic uses of PHI.

Formulation, Characterization and Permeability Studies of Fenugreek (Trigonella foenum-graecum) Containing Self-Emulsifying Drug Delivery System (SEDDS)

Fenugreek is used as a spice and a traditional herbal medicine for a variety of purposes, given its antidiabetic and antioxidant effects. Self-emulsifying drug delivery systems (SEDDS) of herbal drugs are targets of extensive research aiming to increase bioavailability and stability. The study’s objective was to formulate SEDDS containing Trigonella foenum-graecum extract to improve the stability of herbal extract and to increase their permeability through a Caco-2 monolayer. A characterized fenugreek dry extract was used for the formulations, while the SEDDS properties were examined by particle size analysis and zeta potential measurements. Permeability assays were carried out on Caco-2 cell monolayers, the integrity of which was monitored by follow-up trans-epithelial electric resistance measurements (TEER). Cytocompatibility was tested by the MTT method, and an indirect dissolution test was performed, using DPPH antioxidant reagent. Two different SEDDS compositions were formulated from a standardized fenugreek dry extract at either the micro- or the nanoemulsion scale with sufficient stability, enhanced bioavailability of the compounds, and sustained release from HPMC capsules. Based on our results, a modern, non-toxic, cytocompatible fenugreek SEDDS formulation with high antioxidant capacity was developed in order to improve the permeability and bioavailability of all components.

Design, Characterization, and Evaluation of Diosmetin-Loaded Solid Self-microemulsifying Drug Delivery System Prepared by Electrospray for Improved Bioavailability

Diosmetin (DIOS) is a functional compound with poor water solubility, bad permeability, and crystal form. Self-microemulsifying drug delivery system (SMEDDS) was an effective formulation to overcome these shortcomings. In this study, liquid SMEDDS was prepared using Capmul® MCM C8 EP/NF, Cremophor EL, and PEG 400 (2:5.6:2.4, w/w/w) as excipients. Then, the novel technology of electrospray solidified liquid SMEDDS and prepared solid SMEDDS for inhibiting crystallization. Polyvinyl pyrrolidone (PVP) was used as carrier to construct DIOS-loaded solid SMEDDS, with polyethylene oxide (PEO) contributing to the formation of regular sphere in the process of spinning. The particle size of solid SMEDDS (194 ± 5 nm) was much bigger than of liquid SMEDDS (25 ± 1 nm), while DIOS-loaded solid SMEDDS showed greater dissolution rates in pH 1.2 and pH 6.8 media through in vitro drug release study. The solid nanoparticles were smooth and uniform from the graph of a scanning electron microscope (SEM). The graph of a transmission electron microscope (TEM) showed that small droplets were loaded in the matrix. Furthermore, DIOS was encapsulated by matrix in amorphous state via differential scanning calorimetry (DSC) and attenuated total reflection Fourier transform infrared (ATR-FTIR). The crystalline of DIOS was not formed in solid SMEDDS due to the characteristic peaks of DIOS disappeared in X-ray diffraction (XRD) pattern. Therefore, the oral bioavailability of DIOS improved significantly compared with liquid SMEDDS (4.27-fold). Hence, solid SMEDDS could improve the solubility and bioavailability of DIOS, through transfer of the state of crystalline to amorphous by electrospray technology.

Enhanced oral bioavailability and anti-hyperuricemic activity of liquiritin via a self-nanoemulsifying drug delivery system

BACKGROUND

This study focused on the development of a self-nanoemulsifying drug delivery system (SNEDDS) to improve, potentially, the solubility and oral bioavailability of liquiritin (LQ).

METHODS

The solubility of LQ in different types of excipient, namely oils (OLs), emulsifiers (EMs), and co-emulsifiers (CO-EMs), was evaluated, and a pseudo-ternary phase diagram (PTPD) and the formulation optimization were established. The prepared self-nanoemulsifying drug delivery system of liquiritin (LQ-SNEDDS) was assessed using droplet size (DS), zeta potential (ZP), polydispersity index (PDI), droplet morphology, drug release in vitro, and oral bioavailability.

RESULTS

After the dilution of the LQ-SNEDDS, a transparent nanoemulsion was obtained with an acceptable DS (24.70 ± 0.73 nm), ZP (-18.69 ± 1.44 mV), and PDI (0.122 ± 0.006). The LQ-SNEDDS that was developed had a better release rate in vitro than the free LQ suspension. Pharmacokinetic evaluation showed that the relative oral bioavailability of LQ-SNEDDS was increased by 5.53 times, and LQ-SNEDDS exhibited a delayed half life and longer retention time in comparison with those of free LQ. Similarly, LQ-SNEDDS had a better urate lowering effect and provided better organ protection than free LQ at the same dose (P < 0.05).

CONCLUSIONS

The incorporation of LQ into SNEDDS could serve as a promising approach to improve the solubility, oral bioavailability, and anti-hyperuricemic effect of LQ. © 2021 Society of Chemical Industry.

Development of phospholipid complex loaded self-microemulsifying drug delivery system to improve the oral bioavailability of resveratrol

Aim: The aim of this study was to develop a formulation that combines a phospholipid complex (PC) and self-microemulsifying drug delivery system (SMEDDS) to improve the bioavailability of poorly water-soluble resveratrol (RES), called RPC-SMEDDS. Methods: RES-PC (RPC) and RPC-SMEDDS were optimized by orthogonal experiment and central composite design, respectively. The characteristics and mechanism of intestinal absorption were studied by Ussing chamber model. The pharmacokinetics was evaluated in rats. Results: RES was the substrate of MRP2 and breast cancer resistance protein (BCRP) rather than P-gp. The prepared RPC-SMEDDS prevented the efflux mediated by MRP2 and BCRP and improved the bioavailability of RES. Conclusion: These results suggested that the combination system of PC and SMEDDS was a promising method to improve the oral bioavailability of RES.