title: Spectrofluorimetry and chemometrics for investigation of norfloxacin distribution in multilamellar liposomes.
abstract: Norfloxacin (NFX), a fluoroquinolone, was encapsulated in multilamellar liposomes (MLV) of soy-bean phosphatidylcholine at pH 7.0. The observed affinity of this class of drugs for hydrophobic environments, such as phospholipid bilayers, could lead to a better understanding of the mechanism of uptake in bacteria. The fluorescent properties of NFX were examined both free in solution and in MLV, using anisotropy and fluorescence quenching measurements. The latter data was treated with a chemometric method to deconvolute the overlapped spectra of zwitterionic and neutral species of NFX in equilibrium at this pH. The results show that NFX incorporates into the lipidic bilayers with two different distributions of species: the zwitterionic form in the lipid/aqueous interface, and the neutral one, more towards the center of the bilayer.
authors.affiliation: Instituto de Química, UNICAMP, Campinas, S.P., Brazil.
authors.forename: N L
authors.initials: NL
authors.lastname: Zalloum
authors.forename: D N
authors.initials: DN
authors.lastname: Biloti
authors.forename: F B T
authors.initials: FB
authors.lastname: Pessine
mesh_terms: D020106:Acrylamide / Q000737:chemistry; D000890:Anti-Infective Agents / Q000032:analysis / Q000737:chemistry; D001692:Biological Transport; D005454:Fluorescence Polarization; D006863:Hydrogen-Ion Concentration; D007454:Iodides / Q000737:chemistry; D008081:Liposomes / Q000737:chemistry*; D009643:Norfloxacin / Q000032:analysis* / Q000737:chemistry*; D010713:Phosphatidylcholines / Q000737:chemistry; D013025:Glycine max / Q000737:chemistry; D013050:Spectrometry, Fluorescence
chemical_list: D000890:Anti-Infective Agents; D007454:Iodides; D008081:Liposomes; D010713:Phosphatidylcholines; D020106:Acrylamide; D009643:Norfloxacin