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.

Does the Freeze–Thaw Technique Affect the Properties of the Alginate/Chitosan Glutamate Gels with Posaconazole as a Model Antifungal Drug?

“…This anomalous (or non-Fickian) mechanism is known in the literature as pseudo-Fickian diffusion, indicating that in the first step of drug release this process is limited by swelling [ 38 ]. It is consistent with the results obtained by Nikolova et al, who observed n values greater than 0.45 for the release of diclofenac sodium from CS/ALG hydrogels composed of 0.05% ( w/w ) CS and 0.05% ( w/w ) ALG solutions in ratio 1:2 [ 39 ].…”

MOLECULAR DYNAMICS SIMULATIONS OF THE AFFINITY OF CHITIN AND CHITOSAN FOR COLLAGEN: THE EFFECT OF pH AND THE PRESENCE OF SODIUM AND CALCIUM CATIONS

“…The observed trends are understandable considering the acid-base properties of collagen and chitosan. Researchers have documented that chitosan displays typical polyelectrolytic properties that underlie its ability to form complexes with other molecules, such as pharmaceuticals [64] and biopolymers [65,66]. This specific feature of chitosan is associated with the presence of protonated amino groups (pKa ≈ 6.3 [67]), which enables it to interact with negatively charged species.…”

Polyphosphate-Based Hydrogels as Drug-Loaded Wound Dressing: An In Vitro Study

“…In contrast, the maximum loading for LHCl was surprisingly only 50% for gels having a similar swellability. The difference in the loading capacity is therefore likely attributed to electrostatic interactions between the drug and the polymer chains . While DS is in its neutral (COOH) form in acidic conditions, LCHL remains positively charged and hence exhibits electrostatic repulsion with the polymer backbone.…”

“…The difference in the loading capacity is therefore likely attributed to electrostatic interactions between the drug and the polymer chains. 43 While DS is in its neutral (COOH) form in acidic conditions, LCHL remains positively charged and hence exhibits electrostatic repulsion with the polymer backbone. This becomes particularly apparent in samples S4 and S5 (loading capacity of <20%), as these polymers contain the highest content of positively charged APTAC and are therefore the most electrostatically repulsive.…”