title: The use of fluorescence resonance energy transfer to study the disintegration kinetics of liposomes containing lysolecithin and oleic acid in rat plasma.
abstract: OBJECTIVE
  To validate Fluorescence Resonance Energy Transfer (RET) as method to monitor disintegration of fluorescently labeled liposomes varying in lysolecithin/oleic acid (equimolar) content, lysolecithin fatty acid composition and vesicle size in rat blood plasma and buffer.
  
  
  METHODS
  NBD-PE and Rho-PE were used for RET. The measurements were performed on a Perkin Elmer LS-50 spectrofluorimeter. Liposomes were prepared by the extrusion method.
  
  
  RESULTS
  Analysis of the RET data was optimised using a fitting procedure to correct for fluorescence interference by plasma. The disintegration patterns of liposomes could be described by a biexponential decay model. Disintegration rate increased at increasing lysolecithin/oleic acid content and decreasing size. In contrast, all liposomes showed no disintegration in buffer.
  
  
  CONCLUSIONS
  RET is a suitable method to monitor liposome disintegration in non-diluted plasma. Rate and extent of liposome disintegration increases at decreasing liposome size and increasing lysolecithin/oleic acid content.
authors.affiliation: Pharmaceutical and Analytical Development, Novartis AG, Basel, Switzerland. mmadoerin@weleda.ch
authors.forename: M
authors.initials: M
authors.lastname: Madörin
authors.forename: P
authors.initials: P
authors.lastname: van Hoogevest
authors.forename: R
authors.initials: R
authors.lastname: Hilfiker
authors.forename: H
authors.initials: H
authors.lastname: Leuenberger
mesh_terms: D000818:Animals; D004735:Energy Transfer; D008081:Liposomes / Q000097:blood / Q000493:pharmacokinetics*; D008244:Lysophosphatidylcholines / Q000097:blood / Q000493:pharmacokinetics*; D019301:Oleic Acid / Q000097:blood / Q000493:pharmacokinetics*; D051381:Rats; D013050:Spectrometry, Fluorescence / Q000379:methods
chemical_list: D008081:Liposomes; D008244:Lysophosphatidylcholines; D019301:Oleic Acid