title: Optimization of a thermally reversible W/O/W multiple emulsion for shear-induced drug release.
abstract: OBJECTIVE
  The present work aimed at improvement of the formulation of a previously developed thermo-reversible W/O/W multiple emulsion by increasing the emulsion stability and reaching a higher fraction of an encapsulated drug released under shear. The emulsion was based on high molecular weight graft-copolymers of poly(acrylic acid) and Pluronic F127 as stabilizing agents.
  
  
  METHODS
  Once a stable W/O/W thermo-reversible multiple emulsion was obtained via a fine-tuning of the formulation, rheological, granulometric and conductometric tests were performed to assess the thermo-reversible behavior and the fragmentation-release characteristics of the new W/O/W multiple emulsion.
  
  
  RESULTS
  The emulsion exhibited a 10(3) fold increase in viscosity over a range of temperatures from 20 to 40 degrees C. At moderate shearing, a complete release of the marker encapsulated in the internal aqueous phase was observed (99.6%) at 35 degrees C, whereas only 30% was released at 20 degrees C. Under similar conditions at 35 degrees C, slightly more than 50% was released for the initial formula.
  
  
  CONCLUSIONS
  Additionally, the ease of fabrication of the thermo-reversible W/O/W multiple emulsion combined with the complete release under shear at body temperature and the superior emulsion stability suggest numerous applications in the controlled release of drugs.
authors.affiliation: Laboratoire de Physique Pharmaceutique, UMR 8612, Université Paris XI, 5 rue Jean-Baptiste Clément, 92296, Châtenay-Malabry, France.
authors.forename: Laetitia
authors.initials: L
authors.lastname: Olivieri
authors.forename: Monique
authors.initials: M
authors.lastname: Seiller
authors.forename: Lev
authors.initials: L
authors.lastname: Bromberg
authors.forename: Madeleine
authors.initials: M
authors.lastname: Besnard
authors.forename: Thi-Nhat-Liên
authors.initials: TN
authors.lastname: Duong
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Grossiord
mesh_terms: D002626:Chemistry, Pharmaceutical; D004655:Emulsions / Q000737:chemistry* / Q000493:pharmacokinetics*; D009821:Oils / Q000737:chemistry* / Q000493:pharmacokinetics*; D012212:Rheology; D033081:Shear Strength; D013696:Temperature; D014783:Viscosity; D014867:Water / Q000737:chemistry*
chemical_list: D004655:Emulsions; D009821:Oils; D014867:Water