title: Influence of microemulsion-mucin interaction on the fate of microemulsions diffusing through pig gastric mucin solutions.
abstract: Mucus layer, a selective diffusion barrier, has an important effect on the fate of drug delivery systems in the gastrointestinal tract. To study the fate of microemulsions in the mucus layer, four microemulsion formulations with different particle sizes and lipid compositions were prepared. The microemulsion-mucin interaction was demonstrated by the fluorescence resonance energy transfer (FRET) method. Moreover, the microemulsions were observed aggregated into micron-sized emulsions by laser confocal microscopy. We concluded the microemulsion-mucin interaction not only led to microemulsions closely adhered to mucins but also destroyed the structure of microemulsions. At last, the diffusion of blank microemulsions and microemulsion-carried drugs (resveratrol and hymecromone) through mucin solutions was determined by the fluorescence recovery after photobleaching (FRAP) method and the Franz diffusion cell method. The results demonstrated the diffusion of microemulsions was significantly hindered by mucin solutions. The particle size of microemulsions had a negligible effect on the diffusion coefficients. However, the type of lipid played an important role, which could form hydrophobic interactions with mucins. Interestingly, microemulsion-carried drugs with different core/shell locations seemed to suffer different fates in the mucin solutions. The drug incorporated in the oil core of microemulsions, resveratrol, was transported through the mucus layer by the carriers, while the drug incorporated in the surfactant shell of microemulsions, hymecromone, was separated from the carriers and diffused toward the epithelium in the form of free molecules.
authors.affiliation: Laboratory of Biomedical Material Engineering, Dalian Institute of Chemical Physics, Chinese Academy of Sciences , Dalian, People's Republic of China.
authors.forename: Jianbin
authors.initials: J
authors.lastname: Zhang
authors.forename: Yan
authors.initials: Y
authors.lastname: Lv
authors.forename: Bing
authors.initials: B
authors.lastname: Wang
authors.forename: Shan
authors.initials: S
authors.lastname: Zhao
authors.forename: Mingqian
authors.initials: M
authors.lastname: Tan
authors.forename: Guojun
authors.initials: G
authors.lastname: Lv
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Ma
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001702:Biopharmaceutics; D004058:Diffusion; D004337:Drug Carriers / Q000737:chemistry; D016503:Drug Delivery Systems; D004655:Emulsions; D036681:Fluorescence Recovery After Photobleaching; D031541:Fluorescence Resonance Energy Transfer; D005752:Gastric Mucins / Q000737:chemistry*; D006923:Hymecromone / Q000008:administration & dosage; D008055:Lipids / Q000737:chemistry; D010316:Particle Size; D000077185:Resveratrol; D012996:Solutions; D013267:Stilbenes / Q000008:administration & dosage; D013552:Swine; D014783:Viscosity
chemical_list: D004337:Drug Carriers; D004655:Emulsions; D005752:Gastric Mucins; D008055:Lipids; D012996:Solutions; D013267:Stilbenes; D006923:Hymecromone; D000077185:Resveratrol
keywords: Franz diffusion cell; fluorescence recovery after photobleaching (FRAP); fluorescence resonance energy transfer (FRET); interaction; microemulsion; mucin