title: Mucoadhesive polymers: Synthesis and in vitro characterization of thiolated poly(vinyl alcohol).
abstract: The aim of this study was to synthesize thiolated poly(vinyl alcohol) (PVA) and to evaluate its mucoadhesive properties. Thiourea and 3-mercaptopropionic acid were utilized in order to obtain thiolated PVAs, namely, TPVA1 and TPVA2, respectively. TPVA1 and TPVA2 displayed 130.44 ± 14.99 and 958.35 ± 155.27 μmol immobilized thiol groups per gram polymer, respectively, which were then evaluated regarding reactivity of thiol groups, swelling behavior and mucoadhesive properties. Both thiolated PVAs exhibited the highest reactivity at pH 8.0 whereas more than 95% of free thiol groups were preserved at pH 5.0. Thiolation of PVA decelerated water uptake and prolonged disintegration time of test discs compared to unmodified PVA. Contact time of TPVA1- and TPVA2-based test discs on porcine intestinal mucosa was 3.2- and 15.8-fold prolonged, respectively, in comparison to non-thiolated PVA as measured by rotating cylinder method. According to tensile studies on mucosa, the total work of adhesion (TWA) and the maximum detachment force (MDF) were increased when compared to PVA. Furthermore, thiolated PVAs preserved higher percentage of viable cells compared to unmodified PVA within 24h as evaluated by MTT assay. Accordingly, thiolated PVA represents a novel excipient that can likely improve the mucoadhesive properties of various pharmaceutical formulations.
authors.affiliation: Department of Pharmaceutical Technology, Institute of Pharmacy, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria.
authors.forename: Wongsakorn
authors.initials: W
authors.lastname: Suchaoin
authors.affiliation: Department of Pharmaceutical Technology, Institute of Pharmacy, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria.
authors.forename: Irene
authors.initials: I
authors.lastname: Pereira de Sousa
authors.affiliation: Department of Pharmaceutical Technology, Institute of Pharmacy, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria.
authors.forename: Kesinee
authors.initials: K
authors.lastname: Netsomboon
authors.affiliation: Department of Pharmaceutical Technology, Institute of Pharmacy, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria.
authors.forename: Julia
authors.initials: J
authors.lastname: Rohrer
authors.affiliation: Department of Pharmaceutical Technology, Institute of Pharmacy, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria.
authors.forename: Patricia
authors.initials: P
authors.lastname: Hoffmann Abad
authors.affiliation: Department of Pharmaceutical Technology, Institute of Pharmacy, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria.
authors.forename: Flavia
authors.initials: F
authors.lastname: Laffleur
authors.affiliation: Department of Pharmaceutical Chemistry, Institute of Pharmacy, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria.
authors.forename: Barbara
authors.initials: B
authors.lastname: Matuszczak
authors.affiliation: Department of Pharmaceutical Technology, Institute of Pharmacy, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria. Electronic address: andreas.bernkop@uibk.ac.at.
authors.forename: Andreas
authors.initials: A
authors.lastname: Bernkop-Schnürch
mesh_terms: D015097:3-Mercaptopropionic Acid / Q000737:chemistry*; D000268:Adhesiveness; D000818:Animals; D018938:Caco-2 Cells; D002470:Cell Survival / Q000187:drug effects; D065546:Drug Liberation; D006801:Humans; D007413:Intestinal Mucosa / Q000737:chemistry*; D011142:Polyvinyl Alcohol / Q000737:chemistry* / Q000494:pharmacology; D013552:Swine; D013890:Thiourea / Q000737:chemistry
chemical_list: D011142:Polyvinyl Alcohol; D015097:3-Mercaptopropionic Acid; D013890:Thiourea
keywords: 3-Mercaptopropionic acid; Disulfide bonds; Mucoadhesion; Poly(vinyl alcohol); Thiolated polymers; Thiourea