title: Flavonoid-based pH-responsive hydrogels as carrier of unstable drugs in oxidative conditions.
abstract: In this study, pH-responsive hydrogels, synthesized by the coupling reaction of polyacrylic acid and catechin, are proposed as carriers of oxidable drugs toward the GI tract. The presence of polyphenolic moieties in the network gives the polymers properties suitable for the release of unstable drugs in oxidative conditions. The characterization of the hydrogels is obtained by means of morphological and physico-chemical analyses, antioxidant assays and evaluation of the swelling behavior in media simulating the gastric (pH 1.0) and the intestinal (pH 7.4) tracts. The hydrogels are tested as pH-responsive carriers in in vitro release studies of folic acid and thiamine, two model drugs easily degraded by oxidative conditions simulated by UV irradiation and t-butyl hydroperoxide treatment, respectively. Results show that catechin-based carriers are able to control the release of drugs at different pH values, giving a remarkable improvement in the stability of the therapeutics.
authors.affiliation: Department of Pharmacy, Health and Nutritional Sciences, University of Calabria , Rende (CS) , Italy.
authors.forename: Umile Gianfranco
authors.initials: UG
authors.lastname: Spizzirri
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Cirillo
authors.forename: Manuela
authors.initials: M
authors.lastname: Curcio
authors.forename: Nevio
authors.initials: N
authors.lastname: Picci
authors.forename: Francesca
authors.initials: F
authors.lastname: Iemma
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000975:Antioxidants / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology; D002392:Catechin / Q000737:chemistry; D002626:Chemistry, Pharmaceutical / Q000379:methods; D004337:Drug Carriers / Q000737:chemistry*; D065546:Drug Liberation; D004355:Drug Stability; D005419:Flavonoids / Q000737:chemistry*; D005492:Folic Acid / Q000008:administration & dosage / Q000737:chemistry* / Q000494:pharmacology; D020100:Hydrogels; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction; D011108:Polymers / Q000737:chemistry; D013831:Thiamine / Q000008:administration & dosage / Q000737:chemistry* / Q000494:pharmacology
chemical_list: D000180:Acrylic Resins; D000975:Antioxidants; D004337:Drug Carriers; D005419:Flavonoids; D020100:Hydrogels; D011108:Polymers; C006903:carbopol 940; D002392:Catechin; D005492:Folic Acid; D013831:Thiamine
keywords: Catechin; drug release; hydrogels; oxidizable drugs; pH-responsive carrier