Mucoadhesive oligomers and polymers.

Nonparenteral delivery, such as oral, nasal, vaginal, etc., is one of the most advantageous routes for drug administration, offering ease of administration and high patient comfort. The therapeutic efficacy of several drugs, however, is limited by their low aqueous solubility and short residence time in the aimed place/organ of application. Cyclodextrins (CDs) are cyclic sugar oligomers, which are the smallest systems used to solubilize different hydrophobic drugs in water. The biggest challenge of utilizing CDs in drug delivery is that they are not absorbed in, for example, the mucus layer, and therefore, the drug cannot reach a sufficiently high local or systemic therapeutic effect. Besides, polymeric excipients also interact only weakly with the mucus layer but also have another disadvantage, which is their limited biodegradability. This project aims to produce novel CD derivatives and biobased or biodegradable polymers with enhanced mucoadhesive properties. Thiolated and unsaturated polymers are good candidates for prolonging mucosal residence time due to their reaction with the thiol groups of the mucosal layer, resulting in solid covalent bonds, consequently prolonged mucosal residence time. We plan to thiolate several highly water-soluble CDs with our novel thiolation method to reach a high degree of thiolation. Thiolated polyester, which undergoes enzymatic or pH-induced biodegradation, will also be prepared. Another possibility for synthesizing novel mucoadhesive excipients is to produce water-soluble CDs and polymers with double bonds, those reacting with the mucus layer. The synthesis procedures used in this project are novel, cost- effective, and time-effective opportunities, and the novel water-soluble, mucoadhesive CDs, as well as biobased/biodegradable polymers, could be interesting for mucosal drug delivery, but also other bioapplications.