title: Spray-drying nanocapsules in presence of colloidal silica as drying auxiliary agent: formulation and process variables optimization using experimental designs.
abstract: OBJECTIVE
  Spray-drying process was used for the development of dried polymeric nanocapsules. The purpose of this research was to investigate the effects of formulation and process variables on the resulting powder characteristics in order to optimize them.
  
  
  METHODS
  Experimental designs were used in order to estimate the influence of formulation parameters (nanocapsules and silica concentrations) and process variables (inlet temperature, spray-flow air, feed flow rate and drying air flow rate) on spray-dried nanocapsules when using silica as drying auxiliary agent. The interactions among the formulation parameters and process variables were also studied. Responses analyzed for computing these effects and interactions were outlet temperature, moisture content, operation yield, particles size, and particulate density. Additional qualitative responses (particles morphology, powder behavior) were also considered.
  
  
  RESULTS
  Nanocapsules and silica concentrations were the main factors influencing the yield, particulate density and particle size. In addition, they were concerned for the only significant interactions occurring among two different variables. None of the studied variables had major effect on the moisture content while the interaction between nanocapsules and silica in the feed was of first interest and determinant for both the qualitative and quantitative responses. The particles morphology depended on the feed formulation but was unaffected by the process conditions.
  
  
  CONCLUSIONS
  This study demonstrated that drying nanocapsules using silica as auxiliary agent by spray drying process enables the obtaining of dried micronic particle size. The optimization of the process and the formulation variables resulted in a considerable improvement of product yield while minimizing the moisture content.
authors.affiliation: Laboratoire d'Automatique et de Génie des Procédés (LAGEP), UMR 5007 CNRS-UCB Lyon 1, ISPB-UCB Lyon 1, Villeurbanne Cedex, France.
authors.forename: Patrice
authors.initials: P
authors.lastname: Tewa-Tagne
authors.forename: Ghania
authors.initials: G
authors.lastname: Degobert
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Briançon
authors.forename: Claire
authors.initials: C
authors.lastname: Bordes
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Gauvrit
authors.forename: Pierre
authors.initials: P
authors.lastname: Lanteri
authors.forename: Hatem
authors.initials: H
authors.lastname: Fessi
mesh_terms: D002626:Chemistry, Pharmaceutical; D003102:Colloids; D003720:Densitometry; D003890:Desiccation / Q000379:methods; D004339:Drug Compounding; D008855:Microscopy, Electron, Scanning; D015233:Models, Statistical; D053769:Nanocapsules; D010316:Particle Size; D011091:Polyesters / Q000737:chemistry*; D011208:Powders; D012107:Research Design; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties; D013678:Technology, Pharmaceutical / Q000379:methods*; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D003102:Colloids; D053769:Nanocapsules; D011091:Polyesters; D011208:Powders; D014867:Water; C016240:polycaprolactone; D012822:Silicon Dioxide