title: Photostability of barnidipine in combined cyclodextrin-in-liposome matrices.
abstract: BACKGROUND
  The improvement of barnidipine photostability was investigated in cyclodextrin or liposome matrices and in appropriate combinations of these matrices. These supramolecular systems allowed the preparation of liquid formulations, as an alternative to the current solid commercial specialties.
  
  
  METHODS
  Photodegradation stressing tests were performed according to the ICH rules and monitored by derivative spectrophotometry. Optimization was evaluated in terms of drug-inclusion efficiency.
  
  
  RESULTS
  The photodegradation rate of barnidipine in ethanol proved rapid (residual percentage of 29.81%) after a radiation exposure of 225 kJ/m(2). The residual concentrations detected for liposome and cyclodextrin complexes were 42.90 and 72.03%, respectively. The best results were obtained when the drug-cyclodextrin complex was in turn entrapped in liposomes (residual percentage of 90.78%).
  
  
  CONCLUSIONS
  The stability of the drug-in-cyclodextrin-in-liposome system increased significantly with a value close to that of solid formulations whose residual percentage was 96.03%.
authors.affiliation: Department of Pharmacy, Health & Nutritional Sciences, Rende (CS), Italy.
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Ioele
authors.forename: Michele
authors.initials: M
authors.lastname: De Luca
authors.forename: Gaetano
authors.initials: G
authors.lastname: Ragno
mesh_terms: D002626:Chemistry, Pharmaceutical; D003505:Cyclodextrins / Q000737:chemistry*; D000431:Ethanol / Q000737:chemistry; D008027:Light; D008081:Liposomes / Q000737:chemistry*; D009543:Nifedipine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000528:radiation effects; D010782:Photolysis; D013053:Spectrophotometry
chemical_list: D003505:Cyclodextrins; D008081:Liposomes; C050699:mepirodipine; D000431:Ethanol; D009543:Nifedipine