Study Of Stability And Release Kinetics Of Microemulsion In Vitro And In Vivo

Whether microemulsions can be used as efficient oral delivery carriers is one of the research directions of microemulsion applications in recent years.Based on the previous research on microemulsions by the research group,two kinds of microemulsions with different structure were screened to explore the feasibility as a carrier for oral delivery.Simultaneously,the release kinetics data of?-linolenic acid(ALA)-loaded microemulsions were systematically studied,aiming to provide a theoretical basis of the delivery of trophic factors.In the experiment,the physical and chemical properties and microstructure changes of the two microemulsions in the digestive environment were measured by the particle size,polydispersity index(PDI),transmission electron microscopy(TEM),and nuclear magnetic resonance spectroscopy(NMR)etc.Then their biological pathway and toxicity were characterized by animal live imager,which analyzed their stability in vivo and in vitro.Finally,their antioxidant properties were measured by the ABTS method,and their release behaviors were simulated by five kinetic models,which analyzed the release characteristics and the kinetic data of their corresponding structures.The results showed that O/W microemulsion still maintained a spherical structure of 14 nm in the oral and gastric environment,showing good anti-digestive stability.In the intestinal environment,TEM results showed that the microemulsion had an irregular structure.At the same time,NMR results revealed that the functional groups of?₂-CH₂ and?-CH₂were decomposed,which were related to the release of the microemulsion in the intestine.In vivo experiment,O/W microemulsion had obvious fluorescence intensity in liver and kidney.Delivery route needed to pass liver and kidney.In the study of anti-oxidation and release kinetics,ALA-O/W microemulsion exhibited a better antioxidation than unencapsulated ALA.There was high release in intestinal environment,which belonged to Fick Diffusion kinetics,which provided a reliable release kinetic model for O/W microemulsions loaded with active factors.Compared the initial microemulsion,the particle size,TEM and NMR of W/O/W microemulsion remained a slight change in oral and gastric phase.Based on its three-layer molecular structure,the particle size,TEM and NMR of W/O/W microemulsion were also significantly smaller than O/W microemulsion in intestinal environment,showing stronger stability.The fluorescence results at different periods and the measurements of the liver and kidney revealed that W/O/W microemulsion still had a strong fluorescence intensity at 12 h in the animals,showing the potential for slow release.Combined with the high antioxidant and slow release effects of ALA-W/O/W microemulsion,it was more suitable for the transport of active factors in the process of long-acting release.Furthermore,the release kinetics of W/O/W microemulsion in the intestinal environment was consistent with the abnormal transport kinetics of diffusion and erosion coupling.Hence,the difference between W/O/W microemulsion and O/W microemulsion had been proved from the perspective of release kinetics,which provides a basis for the two microemulsions for targeted transport of nutritional factors.