Thiolated pectins: In vitro and ex vivo evaluation of three generations of thiomers

In recent decades, three generations of thiomers have been developed with the main purpose obtaining enhanced interactions mucosal tissues. Therefore, many different types thiolated ligands generated and attached to polymeric backbones. The aim this study was synthesize all directly compare their properties regarding mucus penetration mucoadhesion. Starting from pectin, unprotected thiomer pectin-cysteine (Pec-Cys), preactivated S-protected pectin-cysteine-mercaptonicotinic acid (Pec-Cys-MNA) less reactive pectin-cysteine-glutathione (Pec-Cys-GSH) were synthesized characterised by FT-IR, NMR, colorimetric studies. polymers evaluated cytotoxicity, swelling behaviour, viscosity after mixing mucus, diffusion, into mucosa, amount (Cys, Cys-MNA Cys-GSH) bound polymer determined be in range 193-196 µmol/g. All showed no cytotoxicity. Viscosity mixture Pec-Cys-MNA Pec-Cys-GSH increased 21.5- 26.7-fold, respectively, compared unmodified within 3 hours. Swelling, mucoadhesion, interpenetration diffusion following rank order: Pec-Cys < Pec-Cys-GSH. Results mucoadhesion indicated a 7.4 8.1-fold increase Pec-Cys-GSH, polymer. As exhibited higher mucoadhesive than other thiomers, provides evidence for superior 3rd generation thiomers. Three bearing thiol enhancing interactions. study, on backbone pectin first time penetrating properties. 1st covalently L-cysteine moieties. For 2nd generation, thiols cysteines 2-mercaptonicotinic (MNA), resulting high disulfide bonds. thiol/disulfide exchange glutathione MNA, producing bond. Mucus found as follows: generation. According these results, represents promising excipient strong