SORPTION AND DESORPTION OF STABILIZING AGENTS USED IN 3-PERCENT HYDROGEN-PEROXIDE SOLUTION FOR SOFT CONTACT-LENSES BASED ON POLYHEMA

Abstract

The effects of various stabilizers, acetanilide, phenacetin, propyl gallate and 8-hydroxyquinoline on the stability of 3% hydrogen peroxide solution were examined. From the two different concentrations of stabilizing agents tested, 0.05% acetanilide and 0.01% propyl gallate or 8-hydroxyquinoline were found to be the most effective. Sorption and desorption of these agents by soft contact lenses based on polyHEMA were investigated. The adsorption isotherms of acetanilide, phenacetin and 8-hydroxyquinoline were linear, but propyl gallate obeyed the BET isotherm. Among the substances tested, the minimum sorption occurred with acetanilide. Acetanilide, phenacetin and 8-hydroxyquinoline were not desorbed completely from the contact lens under the conditions discussed in this study, but propyl gallate was sorbed in a reversible manner. The results indicate that propyl gallate is a proper stabilizer for hydrogen peroxide solution used for disinfection of soft contact lenses.