Low and medium molecular weight chitosan matrices with ibuprofen as a potential base for soft capsules for oral use: evaluation of physicochemical properties and molecular structure

Chitosan, which is a biocompatible and biodegradable natural polysaccharide, has been considered as a potential biopolymer-based carrier that can be applied in drug release systems, such as capsules for ibuprofen to overcome physiological barriers. In this study, we have examined three different variants of chitosan matrices for oral administration of ibuprofen (IBU) with various molecular weights (MW) or concentrations - 2% (w/v) and 4% (w/v) low MW, and 2% (w/v) medium MW. Molecular arrangement and physicochemical properties were determined before and after drug release from matrices with two powerful spectroscopic techniques - Raman spectroscopy and Diffuse Reflectance Infrared Fourier Transform DRIFT spectroscopy. It was proved that IBU was successfully incorporated into all studied chitosan matrices, however, the burst and highest drug release was demonstrated for the 2% low MW sample, where more amino and hydroxyl groups were observed interacting with the cationic IBU. It has been shown that chitosan can be an effective drug carrier, improving their pharmacokinetic and pharmacodynamic parameters.