title: A study of free radical release from beta-cyclodextrin-anticancer pro-drugs adducts in water.
abstract: A novel approach in cancer chemotherapy concerns the attempt to employ radical affording substances (RAS) as pro-drugs able to produce irreversible damages on the tumor cell, so stimulating cellular apoptosis. However, radical species can react quickly towards the chemical environment into which they have been generated before reaching their proper sites of action, i.e. the tumor cells. We recently started a study aiming to accomplish new therapeutic systems for the transport of RAS in biological medium. In this paper we report the effect of stabilization produced by beta-cyclodextrin on carbon centered radicals afforded by some mercaptopyridine congeners which have already been shown to possess strong anticancer activity in vitro. EPR experiments carried out on aqueous solutions of N-acyloxy-pyridinethione analogues like 1 (R = adamantyl, cyclohexyl) in the presence of beta-cyclodextrin, demonstrated that photochemically produced alkyl radicals are involved in an adduct with beta-cyclodextrin which works as a cage preventing the interaction of such radicals with the medium. Furthermore, the presence of beta-cyclodextrin has been shown to delay the generation of radicals in water due to a possible interaction between the cyclodextrin cavity and the mercaptopyridine moiety of 1 which is the part of the molecule responsible for beginning the radical event.
authors.affiliation: Pharmaceutical Chemistry Institute, Università degli Studi Carlo Bo, Piazza Rinascimento, 6, 61029 Urbino, Italy. castagnino@uniurb.it
authors.forename: Enzo
authors.initials: E
authors.lastname: Castagnino
authors.forename: Michela
authors.initials: M
authors.lastname: Cangiotti
authors.forename: Serena
authors.initials: S
authors.lastname: Tongiani
authors.forename: Maria Francesca
authors.initials: MF
authors.lastname: Ottaviani
mesh_terms: D000970:Antineoplastic Agents / Q000008:administration & dosage* / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D005079:Excipients; D005609:Free Radicals / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D010782:Photolysis; D011355:Prodrugs / Q000737:chemistry*; D014867:Water / Q000737:chemistry; D047392:beta-Cyclodextrins / Q000737:chemistry*
chemical_list: D000970:Antineoplastic Agents; D005079:Excipients; D005609:Free Radicals; D011355:Prodrugs; D047392:beta-Cyclodextrins; D014867:Water