title: Microencapsulation of nanoemulsions: novel Trojan particles for bioactive lipid molecule delivery.
abstract: BACKGROUND
  Nanoemulsions consist of very stable nanodroplets of oil dispersed in an aqueous phase, typically below 300 nm in size. They can be used to obtain a very fine, homogeneous dispersion of lipophilic compounds in water, thus facilitating their handling and use in nanomedicine. However, the drawback is that they are suspended in an aqueous media. This study proposes a novel technique for drying lipid nanoemulsion suspensions to create so-called Trojan particles, ie, polymer microparticles (around 2 μm) which very homogeneously "entrap" the nano-oil droplets (around 150 nm) in their core.
  
  
  METHODS
  Microencapsulation of the nanoemulsions was performed using a spray-drying process and resulted in a dried powder of microparticles. By using a low-energy nanoemulsification method and relatively gentle spray-drying, the process was well suited to sensitive molecules. The model lipophilic molecule tested was vitamin E acetate, encapsulated at around 20% in dried powder.
  
  
  RESULTS
  We showed that the presence of nanoemulsions in solution before spray-drying had a significant impact on microparticle size, distribution, and morphology. However, the process itself did not destroy the oil nanodroplets, which could easily be redispersed when the powder was put back in contact with water. High-performance liquid chromatography follow-up of the integrity of the vitamin E acetate showed that the molecules were intact throughout the process, as well as when conserved in their dried form.
  
  
  CONCLUSIONS
  This study proposes a novel technique using a spray-drying process to microencapsulate nanoemulsions. The multiscale object formed, so-called Trojan microparticles, were shown to successfully encapsulate, protect, and release the lipid nanodroplets.
authors.affiliation: University of Strasbourg, Faculty of Pharmacy, UMR CNRS 7199 Laboratory of Conception and Application of Bioactive Molecules (Biogalenic Pharmacy team), Illkirch, France.
authors.forename: Xiang
authors.initials: X
authors.lastname: Li
authors.forename: Nicolas
authors.initials: N
authors.lastname: Anton
authors.forename: Thi Minh Chau
authors.initials: TM
authors.lastname: Ta
authors.forename: Minjie
authors.initials: M
authors.lastname: Zhao
authors.forename: Nadia
authors.initials: N
authors.lastname: Messaddeq
authors.forename: Thierry F
authors.initials: TF
authors.lastname: Vandamme
mesh_terms: D002851:Chromatography, High Pressure Liquid; D003890:Desiccation; D016503:Drug Delivery Systems / Q000295:instrumentation*; D004355:Drug Stability; D004655:Emulsions / Q000737:chemistry; D008055:Lipids / Q000008:administration & dosage* / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D050997:Nanomedicine / Q000379:methods; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D024502:alpha-Tocopherol / Q000737:chemistry
chemical_list: D004655:Emulsions; D008055:Lipids; D024502:alpha-Tocopherol