A novel formulation of an ophthalmic beta-adrenoceptor antagonist

To minimize ocular discomfort while maintaining efficacy, a delivery system for a topical cardioselective beta-adrenoceptor antagonist, betaxolol was developed. Betaxolol was formulated at 0.25% concentration in a cationic exchange resin, as a suspension. A polyacrylic acid polymer was added to increase viscosity and to increase residence time in the cul-de-sac. No significant settling was observed throughout a four-week observation period. Thus, resuspension of the formulation by frequent shaking was not required for uniformity. In rabbits, the ocular bioavailability of 0.25% betaxolol suspension was equivalent to that of 0.5% betaxolol solution.