title: Optimization of niosomes for enhanced antibacterial activity and reduced bacterial resistance: in vitro and in vivo evaluation.
abstract: OBJECTIVE
  The aim was to optimize norfloxacin niosomes for enhanced antibacterial activity and reduced bacterial resistance.
  
  
  METHODS
  Pseudomonas aeruginosa, a biofilm forming bacterium, was used as the test organism. Different norfloxacin niosomes were evaluated in vitro and in vivo, respectively, for antibacterial activity compared with aqueous drug solution. The influence of norfloxacin niosomes on biofilm formation was investigated. The interaction of niosomes with bacterial cells was also monitored using the scanning electron microscopy (SEM).
  
  
  RESULTS
  The efficacy of niosomes depended on their composition. Standard niosomes of Span 60 and cholesterol were similar to drug solution. Incorporation of Tween 80, oleic acid (OA), OA/propylene glycol or lecithin produced fluid niosomes which reduced the MIC and inhibited biofilm formation compared with drug solution. Incorporation of a positively charged agent into fluid niosomes enhanced the antibacterial activity and reduced biofilm formation significantly. SEM showed evidence of vesicle adsorption to the bacteria with possible adhesion or fusion with the cell membrane. The in vivo skin model confirmed the in vitro results with optimum niosomes being more efficient than drug solution.
  
  
  CONCLUSIONS
  Niosomes are promising for enhanced antibacterial activity and reduced resistance to antibiotics. The later can be achieved by inhibition of biofilm formation.
authors.affiliation: Tanta University, College of Pharmacy, Department of Pharmaceutical Microbiology , Tanta , Egypt.
authors.forename: Ahmed A
authors.initials: AA
authors.lastname: Abdelaziz
authors.forename: Tarek E
authors.initials: TE
authors.lastname: Elbanna
authors.forename: Fatma I
authors.initials: FI
authors.lastname: Sonbol
authors.forename: Noha M
authors.initials: NM
authors.lastname: Gamaleldin
authors.forename: Gamal M
authors.initials: GM
authors.lastname: El Maghraby
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D005079:Excipients / Q000737:chemistry; D066298:In Vitro Techniques; D008081:Liposomes; D008855:Microscopy, Electron, Scanning; D009643:Norfloxacin / Q000008:administration & dosage / Q000494:pharmacology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects*; D012867:Skin / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D005079:Excipients; D008081:Liposomes; D009643:Norfloxacin
keywords: Pseudomonas aeruginosa; bacterial biofilm; norfloxacin; regrowth assay; surfactant vesicles