title: Elastic liposomes-in-vehicle formulations destined for skin therapy: the synergy between type of liposomes and vehicle.
abstract: OBJECTIVE
  The present study is focused on optimization of elastic liposomes-in-vehicle formulations in respect to drug release and formulation properties. By combining penetration potential of elastic liposomes containing high ratio of entrapped drug and physicochemical properties of vehicles, both affecting the release and texture properties, optimal formulation could be achieved.
  
  
  METHODS
  Deformable, propylene glycol-containing or conventional liposomes with hydrophilic model drug (diclofenac sodium) were incorporated into the following vehicles appropriate for skin application: a hydrogel, a cream base and derma membrane structure base cream (DMS base). Each formulation was assessed for in vitro drug release and mechanical properties.
  
  
  CONCLUSIONS
  The composition and type of both liposomes and the vehicle affected the rate and amount of the released drug. The cream base exhibited the slowest release, followed by the hydrogel and DMS base. Similar release profiles were achieved with both types of elastic vesicles (deformable and propylene glycol liposomes); the slowest release was observed for conventional liposomes, regardless of the vehicle used. The drug release profiles from different liposomes-in-vehicle formulations were in agreement with the physicochemical properties of the formulations. All of the liposomes were found to be compatible with the hydrogel preserving its original textures, whereas a significant decrease in all texture parameters was observed for liposomes-in-DMS base, regardless of liposome type.
  
  
  CONCLUSIONS
  Propylene glycol liposomes-in-hydrogel is considered as the optimal formulation for improving skin delivery of hydrophilic drug. Further investigations involving in vivo animal studies are necessary to confirm its applicability in skin therapy.
authors.affiliation: Department of Pharmaceutics, Faculty of Pharmacy and Biochemistry, University of Zagreb , Zagreb , Croatia and.
authors.forename: Zora
authors.initials: Z
authors.lastname: Palac
authors.forename: Julia
authors.initials: J
authors.lastname: Hurler
authors.forename: Nataša
authors.initials: N
authors.lastname: Škalko-Basnet
authors.forename: Jelena
authors.initials: J
authors.lastname: Filipović-Grčić
authors.forename: Željka
authors.initials: Ž
authors.lastname: Vanić
mesh_terms: D000279:Administration, Cutaneous; D002626:Chemistry, Pharmaceutical; D004008:Diclofenac / Q000008:administration & dosage / Q000737:chemistry / Q000378:metabolism; D016503:Drug Delivery Systems / Q000379:methods*; D004548:Elasticity; D008081:Liposomes / Q000008:administration & dosage / Q000737:chemistry* / Q000378:metabolism*; D012867:Skin / Q000187:drug effects / Q000378:metabolism; D012869:Skin Absorption / Q000187:drug effects / Q000502:physiology
chemical_list: D008081:Liposomes; D004008:Diclofenac
keywords: Cream; deformable liposomes; hydrogel; hydrophilic drug; propylene glycol liposomes; skin; sustained release; texture analysis