title: Pyrocatechol violet as a marker to characterize liposomal membrane permeability using the chelation and the first-order derivative spectrophotometry.
abstract: Pyrocatechol violet (PV), a chelating agent for cupric ions was used to characterize liposomal membrane permeability. After cupric ions were added to PV liposomes, free PV turned into its chelate (PV-Cu), and encapsulated PV kept stable since liposomal membranes prevented metal ions from permeating. After the light scattering background of liposomes and the absorbance of PV were eliminated by the first-order derivative spectrophotometric method, PV-Cu i.e. free PV in liposome suspensions could be determined without separation. The released PV from liposomes could also be determined. Because PV release is relevant to liposomal membrane permeability, PV becomes a marker to characterize the membrane permeability. This new method was simple, rapid, sensitive, and was used to measure the temperature-dependent liposomal membrane permeability in this paper. Dipalmitoylphosphatidylcholine (DPPC) and soybean lecithin liposomes showed the peaks of release at 40 degrees C and 39 degrees C, respectively.
authors.affiliation: Department of Physical Pharmacy, School of Pharmaceutical Sciences, Peking University, Beijing 100083, PR China. jinyg73@hotmail.com
authors.forename: Yiguang
authors.initials: Y
authors.lastname: Jin
authors.forename: Miao
authors.initials: M
authors.lastname: Li
authors.forename: Xinpu
authors.initials: X
authors.lastname: Hou
mesh_terms: D001557:Benzenesulfonates / Q000737:chemistry*; D019327:Copper Sulfate / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry*; D010539:Permeability; D013056:Spectrophotometry, Ultraviolet
chemical_list: D001557:Benzenesulfonates; D008081:Liposomes; C009134:pyrocatechol violet; D019327:Copper Sulfate