title: Characterization of various deformable liposomes with metronidazole.
abstract: OBJECTIVE
  The aim of this study was to investigate various deformable liposomes for their potential application for the vaginal administration of metronidazole.
  
  
  METHODS
  Deformable liposomes composed of egg phosphatidylcholine (EPC) and various surfactants [sodium deoxycholate (SDCh), Tween 80 or Span 80] and conventional liposomes consisting of EPC and egg phosphatidylglycerol-sodium (EPG-Na) were prepared with and without metronidazole. Additionally, a freeze-thaw method was applied to both classes of vesicles (liposomes) containing the drug to improve its trapping capacity. All of the liposomes prepared were characterized and compared in terms of size, polydispersity, zeta potential, entrapment efficiency and their permeability on a Caco-2 cell monolayer.
  
  
  CONCLUSIONS
  Conventional liposomes, both with and without metronidazole, were larger than the deformable vesicles. The presence of ethanol in the preparations of the elastic EPC/SDCh and EPC/Tween 80 liposomes was found to affect the particle size in terms of reducing this parameter. Different types of vesicles were compared for their trapping efficiency of metronidazole and the highest entrapment was observed with conventional liposomes. However, deformable EPC/SDCh liposomes were found to enhance the permeability of metronidazole more effectively than the conventional liposomes based on the in vitro model of the epithelial barrier.
  
  
  CONCLUSIONS
  These preliminary data indicate that EPC/SDCh liposomes may have a promising future in vaginal delivery of metronidazole. Therefore, additional investigations on elastic vesicles and their incorporation in a suitable vehicle should be considered to further evaluate their applicability in vaginal drug delivery.
authors.affiliation: Department of Pharmaceutics, Faculty of Pharmacy and Biochemistry, University of Zagreb, Zagreb, Croatia. zvanic@pharma.hr
authors.forename: Željka
authors.initials: Ž
authors.lastname: Vanić
authors.forename: Anita
authors.initials: A
authors.lastname: Hafner
authors.forename: Margareta
authors.initials: M
authors.lastname: Bego
authors.forename: Nataša
authors.initials: N
authors.lastname: Škalko-Basnet
mesh_terms: D000282:Administration, Intravaginal; D000890:Anti-Infective Agents / Q000008:administration & dosage*; D004337:Drug Carriers / Q000008:administration & dosage / Q000737:chemistry*; D016503:Drug Delivery Systems; D005260:Female; D006801:Humans; D008081:Liposomes / Q000737:chemistry*; D008795:Metronidazole / Q000008:administration & dosage*; D008962:Models, Theoretical; D010316:Particle Size
chemical_list: D000890:Anti-Infective Agents; D004337:Drug Carriers; D008081:Liposomes; D008795:Metronidazole