US Patent 4,738,851
United States Patent and Trademark Office
University of Iowa Research Foundation (Iowa City, IA, US)
An ophthalmic gel for topical application to the conjunctival sac of the eye. The gel comprises an ophthalmic drug carried in a gel which provides good ocular retention while avoiding burst release of medicament and yet at the same time providing controlled release of the medicament. The gel contains in combination sodium carboxymethyl-cellulose and colloidal magnesium aluminum silicate. A combination of these ingredients in the gel provides the desired effects.
Schoenwald, Ronald D. and Lach, John L. Controlled release ophthalmic gel formulation. US Patent 4,738,851 filed June 12, 1986 and issued April 19, 1988. https://ir.uiowa.edu/patents/57