DIALDEHYDE OXYNANOCELLULOSE AS A NEW MUCOADHESIVE MATERIAL

Cellulose and its derivatives are biodegradable and biocompatible polymers and have a large potential to be used in many applications. Dialdehyde oxynanocellulose (DAONC) is one of the new cellulose derivatives produced by regioselective oxidation C2, C3 and C6 hydroxyl groups of cellulose using oxidation agents [1]. In this work, we synthesized DAONC from microcrystalline cellulose (MCC) using two oxidation steps. Potassium permanganate was used for oxidation of C6 group at the first step and sodium periodate was used to oxidize the C2 and C3 hydroxyl groups at the second step. The formation of carboxyl groups was confirmed by FTIR study and conductometric method. In contrast to the spectrum of the MCC, a new absorption band appears in the FTIR spectra of ONCs at 1720 cm–1, which is related to the stretching vibration of C=O in carboxyl group. The characteristic absorption band of carbonyl groups of DAONC appeared 1730 cm−1 for Calculations of the results of conductometric titration showed the amount of carboxyl groups to be 0.8-1.1 mmol/g (1 figure). Figure 1. FTIR spectra of NC (1), ONC (2). Mucoadhesive properties of DAONC were evaluated using the tensile test and fluorescent microscopy methods. The retention of DAONC was evaluated in vitro on sheep oral mucosal tissue using artificial saliva. The tensile test results showed that DAONC was significantly more mucoadhesive compared to ONC. The force of detachment or adhesive strength indicates the force required to overcome the adhesive bonds between the polymer materials and mucosa. The superior mucoadhesive behavior of DAONC is likely due to the presence of a higher percentage of carboxyl and aldehyde groups that formed covalent bonds with thiols of mucin present on the mucosal surface [2]. New nanocellulose derivatives with enhanced mucoadhesive properties could be of interest for application in transmucosal drug delivery. These mucoadhesive nanocellulose derivatives may be used in the future to develop formulations with various active pharmaceutical ingredients. To the best of our knowledge, this is the first study reporting the chemical modification of nanocellulose with the aim to enhance its mucoadhesive properties Reference Isogai A, Saito T, Fukuzumi H. TEMPO-oxidized cellulose nanofibers. Review Nanoscale, 2011,3,71 T. Ways, W. Lau, V. Khutoryanskiy, chitosan and Its Derivatives for application in mucoadhesive drug delivery systems Polymers. 2018, 10, 3, 267. A. Bernkop-Schnurch, S. Steininger, Int. J. Pharm. 2000, 194, 239