The Effect of Gamma Irradiation on the Swelling Process of Carbomers and the Functional Properties of Gels Based on Them

The swelling processes of carbomers—various modifications of lightly crosslinked polyacrylic acid—in water have been studied depending on the γ-irradiation dose. It has been found that the swelling kinetics are primarily described by second-order rate equations. Irradiation was shown to reduce the degree of swelling and increase the crosslink density; these effects were less pronounced in the case of irradiation in a vacuum. Rheological tests of gels based on irradiated carbomers demonstrated a decrease in viscosity with increasing dose, which can be explained by both radiation destruction and modification of carboxyl groups that weakens the polyelectrolyte effect. The carbomer structural features are noted to influence swelling and the properties of gel systems. A study of diclofenac sodium release from gels has shown that irradiation of Carbomer 141G with a dose of 30 kGy significantly increases the yield of the drug, indicating the potential of using ionizing radiation to enhance the delivery of biologically active substances.