FACTORS INFLUENCING DRUG AND PROTEIN-TRANSPORT AND RELEASE FROM IONICHYDROGELS

The effect of polymer structural parameters of ionic hydrogels on the transport of drugs and proteins has been studied for a number of anion ic and cationic hydrogels. Crosslinked anionic hydrogels were composed of acrylic acid and 2-hydroxyethyl methacrylate, whereas cationic hyd rogels were based on diethyl aminoethyl acrylate or diethyl aminoethyl methacrylate and a-hydroxyethyl methacrylate. The hydrogel structure was investigated using dynamic swelling studies to deduce the variatio n of mesh size available for solute transport as a function of environ mental parameters including the pH and ionic strength. For anionic hyd rogels, the mesh size increased with increasing pH due to the ionizati on of the network. The reverse was true for cationic hydrogels. Ioniza ble drugs and proteins could interact with the ionizable hydrogels dur ing the transport process. The solute size also affected the release b ehavior, causing additional hindrance and decreased mobility.