title: Ciprofloxacin encapsulation into giant unilamellar vesicles: membrane binding and release.
abstract: This study aimed at investigating some respects of binding and interaction between water-soluble drugs and liposomal carrier systems depending on their size and lamellarity. As model substance, ciprofloxacin hydrochloride (CPFX) was incorporated into giant unilamellar vesicles (GUVs) to study their CPFX encapsulation/binding capacity. To characterize molecular interactions of various CPFX microspecies with lipid bilayer, zeta potential and electron paramagnetic resonance (EPR) spectroscopy measurements were performed. The increase of the zeta potential at pH 5.4 but no change at pH 7.2 was interpreted in terms of the CPFX microspecies' distribution at the two pH values. EPR observations showed an increased fluidity because of CPFX binding to GUVs. We worked out and applied a three-compartment dialysis model to separately determine the rate of drug diffusion through the liposomal membrane. Equilibrium dialysis showed (a) different permeation of CPFX through the membranes of GUVs and multilamellar vesicles (MLVs), with characteristic half-lives of 54.4 and 18.1 h, respectively; and (b) increased retention of CPFX in case of GUVs with released amounts of 70% compared with about 97% in case of MLVs. Our results may provide further details for efficient design of liposomal formulations incorporating water-soluble drugs.
authors.affiliation: Department of Biophysics and Radiation Biology, Faculty of Medicine, Semmelweis University, Budapest, Hungary.
authors.forename: Nóra
authors.initials: N
authors.lastname: Kaszás
authors.forename: Tamás
authors.initials: T
authors.lastname: Bozó
authors.forename: Marianna
authors.initials: M
authors.lastname: Budai
authors.forename: Pál
authors.initials: P
authors.lastname: Gróf
mesh_terms: D002626:Chemistry, Pharmaceutical / Q000379:methods*; D002939:Ciprofloxacin / Q000138:chemical synthesis* / Q000378:metabolism; D004339:Drug Compounding / Q000379:methods*; D008051:Lipid Bilayers / Q000378:metabolism; D008081:Liposomes; D008560:Membrane Fluidity / Q000502:physiology; D011485:Protein Binding / Q000502:physiology; D053835:Unilamellar Liposomes / Q000138:chemical synthesis* / Q000378:metabolism
chemical_list: D008051:Lipid Bilayers; D008081:Liposomes; D053835:Unilamellar Liposomes; D002939:Ciprofloxacin