title: Mucoadhesion mechanism of chitosan and thiolated chitosan-poly(isobutyl cyanoacrylate) core-shell nanoparticles.
abstract: The study is focused on the evaluation of the potential bioadhesive behaviour of chitosan and thiolated chitosan (chitosan-TBA)-coated poly(isobutyl cyanoacrylates) (PIBCA) nanoparticles. Nanoparticles were obtained by radical emulsion polymerisation with chitosan of different molecular weight and with different proportions of chitosan/chitosan-TBA. Mucoadhesion was ex vivo evaluated under static conditions by applying nanoparticle suspensions on rat intestinal mucosal surfaces and evaluating the amount of nanoparticles remaining attached to the mucosa after incubation. The analysis of the results obtained demonstrated that the presence of either chitosan or thiolated chitosan on the PIBCA nanoparticle surface clearly enhanced the mucoadhesion behaviour thanks to non-covalent interactions (ionic interaction and hydrogen bonds) with mucus chains. Both, the molecular weight of chitosan and the proportion of chitosan-TBA in the formulation influenced the nanoparticle hydrodynamic diameter and hence their transport through the mucus layer. Improved interpenetration ability with the mucus chain during the attachment process was suggested for the chitosan of high molecular weight, enhancing the bioadhesiveness of the system. The presence of thiol groups on the nanoparticle surface at high concentration (200 x 10(-6) micromol SH/cm2) increased the mucoadhesion capacity of nanoparticles by forming covalent bonds with the cysteine residues of the mucus glycoproteins.
authors.affiliation: Laboratoire de Physicochimie, Pharmacotechnie et Biopharmacie, UMR CNRS 8612, Université Paris Sud, Faculté de Pharmacie, 5, Rue J.B. Clément, 92296 Chatenay-Malabry, France.
authors.forename: Irene
authors.initials: I
authors.lastname: Bravo-Osuna
authors.forename: Christine
authors.initials: C
authors.lastname: Vauthier
authors.forename: Alessandra
authors.initials: A
authors.lastname: Farabollini
authors.forename: Giovanni Filippo
authors.initials: GF
authors.lastname: Palmieri
authors.forename: Gilles
authors.initials: G
authors.lastname: Ponchel
mesh_terms: D000268:Adhesiveness; D000818:Animals; D002448:Cell Adhesion; D048271:Chitosan / Q000737:chemistry*; D003487:Cyanoacrylates / Q000737:chemistry*; D004337:Drug Carriers; D004659:Enbucrilate; D008297:Male; D008970:Molecular Weight; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D011108:Polymers / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013455:Sulfur / Q000737:chemistry; D013816:Thermodynamics
chemical_list: D003487:Cyanoacrylates; D004337:Drug Carriers; D011108:Polymers; D013438:Sulfhydryl Compounds; D013455:Sulfur; D048271:Chitosan; D004659:Enbucrilate