OPTIMIZED RELEASE OF DEXAMETHASONE AND GENTAMICIN FROM A SOLUBLE OCULAR INSERT FOR THE TREATMENT OF EXTERNAL OPHTHALMIC INFECTIONS

In the case of external ophthalmic infections, repeated instillations of antibiotics are required to reach therapeutic level, above the mini mal inhibitory concentration (MIG). An additional administration of a corticosteroid is often needed, in order to limit the precorneal damag es caused by the infection. However, repeated administration of a cort icosteroid can increase intraocular pressure and thus lead to glaucoma . To overcome the disadvantages of separated and repeated instillation s of two products and to avoid the side effects of dexamethasone, a so luble insert containing gentamicin sulfate and dexamethasone phosphate was developed. The new system ensures the concomitant release of the two drugs during the first 10 h of treatment, followed by an adequate concentration of gentamicin sulfate, above the MIC of 4.0 mu g ml(-1), during 50 h, due to a combination of gentamicin sulfate with cellulos e acetate phthalate, which reduces the solubility of gentamicin. (C) 1 998 Elsevier Science B.V.