Studies on the influence of auxiliary substances on the physico-chemical characteristics of ophthalmic drugs. Part I. Studies on the influence of auxiliary substances on the critical micellar concentration of surfactants solutions in eye drops containing sulphacetamidum natricum

Interactions between Tweens, surfactants used in eye drops and the remaining compounds of the preparations were investigated. The interactions were assessed by means of the surface tension measurement method. Obtained results demonstrate that the substances used in the facture of the preparation affect the critical micellar concentrations of Tweens. Only hydroxyethylcellulose was found to exert a stabilizing effect on the critical micellar concentration of these substances. The amount of used surfactant should be taken into consideration in the manufacture of eye preparations.