title: Characteristics and photo-responsive release property of liposome containing 7-acetoxy coumarin.
abstract: A photo-responsive liposome was developed by loading 7-acetoxy coumarin (ATC) in egg phosphatidylcholine (EPC) liposome. ATC was derivetized from 7-hydroxy coumarin using sodium acetate. The ATC-loaded liposomes were prepared by suspending the dry mixture film of ATC/EPC in distilled water and sonicating the suspension. When the ATC to EPC ratio was less than 1:8, homogeneous liposomal suspensions were obtained without any precipitate. On 1H NMR spectra, the unsaturated chains of liposomal EPCs were somewhat deteriorated by a subsequent irradiation, the irradiation of lambda = 365 nm and then the irradiation of lambda = 254 nm. On TEM photos, the size of liposomes incorporating ATC markedly increased by the subsequent irradiation. Photo-dimerization (under lambda = 365 nm) and de-dimerization (under lambda = 254 nm) of ATC took a place even in EPC liposomes. Upon the irradiation of lambda = 254 nm, liposome containing ATC dimers exhibited an enhanced release of 5(6)-carboxyfluorescein compared with liposome containing ATC monomer and liposome free of ATC. The de-dimerization of ATC dimers is believed to fluidize the liposomal membrane and promote the release.
authors.affiliation: Division of Biotechnology and Bioengineering and Institute of Bioscience and Biotechnology, Kangwon National University, 192-1, Hyoja 2-dong, Chuncheon-si, Kangwon-do 200-701, Korea.
authors.forename: Hee Jin
authors.initials: HJ
authors.lastname: Seo
authors.forename: Jin-Chul
authors.initials: JC
authors.lastname: Kim
mesh_terms: D003374:Coumarins / Q000737:chemistry*; D019281:Dimerization; D004355:Drug Stability; D008081:Liposomes / Q000737:chemistry* / Q000528:radiation effects; D046529:Microscopy, Electron, Transmission; D019906:Nuclear Magnetic Resonance, Biomolecular; D010713:Phosphatidylcholines / Q000737:chemistry; D055668:Photochemical Processes; D019346:Sodium Acetate; D017550:Spectroscopy, Fourier Transform Infrared; D014466:Ultraviolet Rays
chemical_list: D003374:Coumarins; D008081:Liposomes; D010713:Phosphatidylcholines; D019346:Sodium Acetate