Preliminary In Vivo Ocular Tolerance Assessment of a Cefuroxime Sodium Suspension in Self-Emulsifying Oil

Cefuroxime sodium (CEF) is a second-generation cephalosporin that remains unstable in an aqueous environment. The answer to this low stability may be self-emulsifying oils, which are isotropic mixtures of oil and surfactants, in which the stability of CEF has already been proven. Self-emulsifying oils are well known for their ability to enhance the solubility and bioavailability of lipophilic drugs. This research presents a preliminary in vivo study of an innovative approach to develop eye drops in the form of a self-emulsifying oil (SEO) containing suspended water-labile antibiotic cefuroxime sodium. Such a concept has never been explored before. Upon contact with tear fluid, the preparation rapidly forms an emulsion, allowing for the rapid dissolution of the antibiotic. The aim of the study was to assess the tolerability of such eye drops. CEF (5% <i>w</i>/<i>w</i>) was suspended in SEO carriers, prepared by dissolving surfactants (Tween 20; 5% <i>w</i>/<i>w</i>) in Miglyol. The in vivo evaluation was conducted on rabbits after two once-a-day applications of the eye drops. The study demonstrated the safety of both the SEO-placebo and the SEO containing suspended CEF. The formulations did not affect the appearance of the cornea and iris. During the observations, only changes in the conjunctiva of the eye were noted, which manifested as conjunctival hyperemia. The result of the Draize test was an average of 3.3 points out of 110 possible points, which classifies the CEF-SEO suspension as minimally irritating.