title: Optimization of particle size and encapsulation efficiency of vancomycin nanoparticles by response surface methodology.
abstract: BACKGROUND
  Treating vancomycin-resistant Staphylococcus aureus strains requires high doses of vancomycin, which might lead to adverse reactions such as nephrotoxicity and "red neck syndrome". Use of nanotechnology for antibiotic delivery is a promising approach to overcome antibiotic-resistance.
  
  
  OBJECTIVE
  The objective of this study was optimizing the particle size and encapsulation efficiency (EE) of vancomycin nanoparticles prepared from chitosan.
  
  
  METHODS
  The nanoparticles were prepared by ionotropic gelation method, at different combinations of chitosan concentration, chitosan/tripolyphosphate mass and vancomycin/chitosan mass, using Box-Behnken experimental design. Dynamic light scattering and ultracentrifugation were used to measure the nanoparticle size and EE, respectively. Vancomycin was quantified in samples by spectrophotometery. The optimum conditions were determined by subsequent regression analysis and multicriteria decision analysis of the output data.
  
  
  RESULTS
  The nanoparticle size and EE were greatly influenced by the independent variables, which had interactive effects on both responses. The optimum conditions for production of nanoparticles were chitosan concentration of 0.5-1.2 mg/ml, chitosan/tripolyphosphate mass ratio of 3-3.5 and vancomycin/chitosan mass ratio of 1, which yielded nanoparticles between 130 and 150 nm with encapsulation efficiencies of 60-69%.
  
  
  CONCLUSIONS
  The size and EE of vancomycin nanoparticles were optimized by the proposed procedure.
authors.affiliation: Department of Pharmaceutics, Faculty of Pharmacy, Mazandaran University of Medical Sciences , Sari , Iran and.
authors.forename: Soheyla
authors.initials: S
authors.lastname: Honary
authors.forename: Pouneh
authors.initials: P
authors.lastname: Ebrahimi
authors.forename: Roja
authors.initials: R
authors.lastname: Hadianamrei
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D048271:Chitosan / Q000737:chemistry*; D004337:Drug Carriers / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D011122:Polyphosphates / Q000737:chemistry; D014640:Vancomycin / Q000008:administration & dosage*
chemical_list: D000900:Anti-Bacterial Agents; D004337:Drug Carriers; D011122:Polyphosphates; D014640:Vancomycin; D048271:Chitosan; C005692:triphosphoric acid