HYDROGELS FROM XYLAN/CHITOSAN COMPLEXES: USE OF SODIUM CITRATE TO IMPROVE DRUG LOADING AND RELEASE PROCESSES

CARLA N. SCHNELL; MARÍA V. GALVÁN; MIGUEL A. ZANUTTINI; PAULINA MOCCHIUTTI

Córdoba

Workshop; IWBLCM, 2nd International Workshop on Biorefinery of Lignocellulosic Materials; 2019

Nanocelia, Junta de Andalucía

Hydrogels were prepared from colloidal suspensions of polyelectrolyte complexes (PECs) of xylan (Xyl) and chitosan (Ch) (mass ratio: 70 wt% Xyl / 30 wt% Ch). Sodium citrate solution at different concentration (3% and 7% w/v) was used as an ionic crosslinking agent to improve the drug release control. Hydrogels were characterized by means of FTIR, scanning electron microscopy, mechanical properties, swelling and solubility. FTIR spectra confirmed the presence of sodium citrate in crosslinked hydrogels. Comparing with non-crosslinked hydrogels, wet-stress and wet-strain at break were increased by 150% and 57%, respectively when hydrogels were treated with 7% w/v of sodium citrate. The swelling of non-crosslinked hydrogels in PBS (phosphate buffer saline) at pH 7.4 was clearly modified due to the ionic strength of the liquid medium. The drug loading process was made by immersing the hydrogels in sodium diclofenac solutions for 20 h and at pH 7.4. It was found that at pH 7.4, crosslinked hydrogel absorbed significantly higher amounts of diclofenac sodium compared to non-crosslinked hydrogels. In the drug loading process, the sodium citrate present in the hydrogels was totally released to the liquid medium. These allowed us to conclude that an ion exchange process occurred between sodium citrate and diclofenac sodium. Drug release process was made in PBS medium at pH 7.4 and 37ºC. It was found that the diclofenac sodium absorbed in the sodium citrate treated hydrogels was controlled released. Results suggest that these hydrogels based on biodegradable polyelectrolytes have potential application as drug delivery system.