EVALUATION OF HYDROGELS OBTAINED FROM POLYACRYLAMIDE AND POLY (VINYL ALCOHOL) LOADED WITH A LOCAL ANESTHETIC (LIDOCAINE HYDROCHLORIDE)

Abstract

Physicochemical interactions between a polymeric matrix and an anesthetic solution were investigated as a potential material for local dressings. Different types of hydrogels were synthesized: from polyacrylamide (PAAm), from modified PAAm with NaOH (forming polyelectrolytic networks, product of basic hydrolysis) and finally, hydrogels from semi-interpenetrated networks (semi-IPN) of PAAm/poly (vinyl alcohol), (synthesized in ratios PAAm/PVA 90/10 and 60/40 %m/m). The xerogels were loaded with the local anesthetic lidocaine hydrochloride, their chemical structure and the absorption of lidocaine was characterized by Fourier transform infrared spectroscopy (FTIR), while the hydrogels' ability to release anesthesia was monitored by UV spectrometry. The hydrolyzed hydrogels expanded three times more in lidocaine than the other hydrogels, the FTIR indicated that carboxylate groups formed during the hydrolysis process, which favored the expansion of the network. In the semi-IPN PAAm/PVA hydrogels the swelling decreased at higher concentrations of the fed PVA. Consequently, by increasing the concentration of PVA in the network from 10 to 40% m / m, the concentration of lidocaine released was lower and the elution rate was 5 times slower, achieving the release of 242.06 mg·L-1 after 240 min.