Title
Acrylates and methylcellulose based hydrogels. Synthesis swelling properties and applications to inclusion and controlled release of bioactive matters
Authors
C. POHONTU M. POPA J. DESBRIERES and L. VERESTIUC

Received This manuscript is presented to celebrate the 50^th anniversary of Cellulose Chemistry and Technology since its foundation by Prof. Cristofor I. Simionescu and other famous chemists in the field of wood and cellulose chemistry.
Published Volume 50 Issue 5-6 May-June
Keywords hydrogels, acrylic monomers, methylcellulose, semi-IPN, swelling, drug release

Abstract
Polymeric networks with semi-interpenetrated structure (semi-IPN) have been obtained by crosslinked polymerization of 2-hydroxyethyl methacrylate, acrylic acid and triethylene glycol dimethacrylate, in the presence of methylcellulose. FTIR data confirmed the network formation and indicated strong interactions between the hydrophilic groups of the formed synthetic matrix and methylcellulose. Thermal analysis indicated that single phase materials were obtained with a Tg situated around 125 °C. The kinetics of swelling revealed a non-Fickian diffusion, the values for the diffusional coefficient n suggesting that the penetration rate of buffer molecules into the hydrogels and the polymeric network relaxation were comparable; the anomalous behaviour was favoured by the presence of the methylcellulose in the semi IPN network. The maximal degree of swelling was reached for the hydrogels with increased content of methylcellulose. Carteolol hydrochloride, a beta-adrenoceptor blocking agent was included by diffusion into the hydrogels and drug release studies were performed in a buffered solution. The release profile varied according to the content of methylcellulose, monomers and crosslinker. The presence of methylcellulose and acrylic acid determined the release of the drug due to the interactions between the ionized species. The physico-chemical characteristics and in vitro release studies indicate that the prepared hydrogels are promising materials for ophthalmic drug delivery applications.