Polyelectrolyte complexes of chitosan and sodium alginate as a drug delivery system for diclofenac sodium

Abstract Polyelectrolyte complexes (PECs) have unique physicochemical properties which make them very interesting for pharmaceutical applications and particularly as drug delivery systems. The aim of this work was to obtain PECs based on the biocompatible and biodegradable biopolymers chitosan and sodium alginate and to apply them as a drug delivery system for sustained release of diclofenac sodium. Three complexes with different ratios between the two polyions were obtained. Their structure and properties were investigated using dynamic light scattering, microscopy methods (optical, scanning and transmission electron microscopy), infrared spectroscopy, X‐ray diffraction. The drug entrapment efficiency of the various PECs was assessed and the release profiles were monitored. In this way the relationship between the composition of the PECs and the drug release profiles was outlined. The fibrillar form of the chitosan/alginate PECs was demonstrated to exert specific control over the diclofenac release which makes these materials appropriate as vehicles for controlled diclofenac sodium release. © 2021 Society of Industrial Chemistry.