Synthesis and characterization of hydrogels composed by different types of poly(vinyl alcohol)

Abstract

PVA is a synthetic water-soluble, biodegradable and biocompatible polymer. It is widely used in pharmaceutical and biomedical applications for controlled drug release. The basic properties of PVA are known to depend upon the degree of polymerization and on the degree of hydrolysis as well. Thus, the aim of this study was to develop a hydrogel with improved mechanical properties and also evaluate the influence of the different PVAs in the hydrogels properties in order to assess their potential application in matrices for advanced controlled drug release systems. The hydrogels were synthesized with agar, carrageen and PVAs holding different hydrolysis (88 and 98 %) rates and molecular weight using gamma radiation from 60Co source in order to promote an adequate crosslinking and sterilization simultaneously. The properties of the hydrogels formed were determined by the analysis of the swelling ratio, gel content and mechanical properties. The results indicated the matrices composed by partially hydrolyzed grade PVA presented enhanced mechanical properties and crosslinking over the fully hydrolyzed grade. The properties of the PVA used for the preparation of the evaluated hydrogels conferred different properties to the hydrogels and the molar mass played an important role in the crosslinking process of fully hydrolyzed PVA grades.