Preparation and characterization of acrylic hydrogels neutralized by basicamino acids

Basic amino acids were used as neutralizers in the gellation of Eudispert(R ) as an acrylic hydrogel. Arginine and lysine successfully neutralized Eudi spert, as did sodium hydroxide, and formed hydrogels. A gentle rise of pH w as observed as the dosage of the base increased when arginine and lysine we re used, in contrast to the sharp rise of pH observed when sodium hydroxide was used, The rank of viscosity of the prepared hydrogels was as follows: lysine>arginine>NaOH. The release rate of model drugs (salicylic acid, theo phylline, and bovine Insulin) from the prepared hydrogels ranked as follows : NaOH>lysine>arginine, the sustained-release profile being observed,vith a rginine, The rate of diffusion of the model drug from the hydrogel was inve rsely proportional to the molecular weight of the cationized neutralizer us ed. It is concluded that the strategy of neutralization of acidic polymers by basic amino acids has advantage with the respect to both the sustained-r elease characteristics of the gel and the biocompatibility of the basic ami no acids themselves.