Curcumin–Sodium Alginate and Curcumin–Chitosan Conjugates as Drug Delivery Systems: An Interesting Rheological Behaviour

Abstract

The conjugation of polyphenols is a valuable strategy with which to confer tailored properties to polymeric materials of biomedical interest. Within this investigation, we aim to explore the possibility to use this synthetic approach to increase the viscosity of conjugates, thus allowing the release of a loaded therapeutic to be better controlled over time than in neat polyphenols. Curcumin (CUR) was conjugated to sodium alginate (CA) and chitosan (CS) with functionalisation degrees of 9.2 (SA-CUR) and 15.4 (CS-CUR) mg g−1. Calorimetric analyses showed higher degrees of chain rigidity upon conjugation, with a shift of the degradation peaks to higher temperatures (from 239 to 245 °C and from 296 to 303 °C for SA-CUR and CS-CUR, respectively). Rheological analyses were used to prove the enhanced interconnection between the polymer chains in the conjugates, confirmed by the weak gel parameters, A and z. Moreover, the typical non-Newtonian behaviour of the high-molecular-weight polysaccharides was recorded, together with an enhancement of the activation energy, Ea, in CS-CUR vs. CS (opposite behaviour recorded for SA-CUR vs. SA). The evaluation of the delivery performance (of Doxorubicin as a model drug) showed sustained release profiles, opening opportunities for the development of controlled delivery systems.

Optimization of the Green Extraction of Red Araçá (Psidium catteyanum Sabine) and Application in Alginate Membranes for Use as Dressings

“…Karroubi et al [ 13 ] prepared chitosan membranes with sodium alginate incorporated with Teucrim polium extract and obtained a healing rate of 98%, surpassing healing ointment and commercial elastic bandages. In terms of phytochemical release, Cirillo et al [ 14 ] associated curcumin and sodium alginate and obtained satisfactory results, reinforcing the ability of alginate to release compounds of interest in a controlled environment.…”