title: Evaluating the mucoadhesive properties of drug delivery systems based on hydrated thiolated alginate.
abstract: Mucoadhesive polymers have been proposed as drug delivery carriers due to their ability to adhere to the mucus layer. A relatively new class of mucoadhesive polymers, termed thiomers, was suggested as an improved carrier capable of creating disulfide covalent bond with the mucus. Since the wet physiological environment is likely to cause any delivery system to adsorb water and arrive hydrated to its target, studying the performance of mucoadhesive systems in their hydrated form is of major importance. Model thiomer, alginate-thiol, were synthesized and characterized the product using Nuclear Magnetic Resonance (NMR), Fourier Transform Infra Red spectroscopy (FTIR). The swelling behavior was determined gravimetrically and found to be affected from the thiolation. Interactions between the alginate-thiol and mucin glycoproteins, which are believed to be an outcome of disulfide bonds, were verified using rheology experiments. Adhesion of hydrated tablets with different cross linking densities to porcine's fresh small intestine tissue were characterized using a Lloyd Tensile Machine. It was shown that the thiolation did not improve the adhesion properties of hydrated tablets. It appears that the benefit achieved by adding thiol group to the polymer in dry tablet form was flawed in hydrated form due to formation of inter-molecular disulfide junctions.
authors.affiliation: Department of Chemical Engineering, Technion, Haifa 32000, Israel.
authors.forename: Maya
authors.initials: M
authors.lastname: Davidovich-Pinhas
authors.forename: Offer
authors.initials: O
authors.lastname: Harari
authors.forename: Havazelet
authors.initials: H
authors.lastname: Bianco-Peled
mesh_terms: D000268:Adhesiveness; D000464:Alginates / Q000138:chemical synthesis / Q000737:chemistry*; D004337:Drug Carriers / Q000138:chemical synthesis / Q000737:chemistry*; D005782:Gels / Q000737:chemistry; D020723:Glucuronic Acid / Q000138:chemical synthesis / Q000737:chemistry; D006603:Hexuronic Acids / Q000138:chemical synthesis / Q000737:chemistry; D012212:Rheology; D013438:Sulfhydryl Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D014783:Viscosity; D014867:Water / Q000737:chemistry
chemical_list: D000464:Alginates; D004337:Drug Carriers; D005782:Gels; D006603:Hexuronic Acids; D013438:Sulfhydryl Compounds; D014867:Water; D020723:Glucuronic Acid