Biopharmaceutical Study of Certain Corticosteroid and Phenylephrine Hydrochloride in Ophthalmic Preparations

In topical ophthalmic medication, both of the drug reservoir, viz. ophthalmic preparation, and the physio¬logical transport fluid, viz. the tears, are exposed to the target biologic membrane in an open system. This situation has far reaching implications with regard to drug loss or drug action.The rationale ot the research presented here was to find out the optimum conditions for the minimization of ocular drug loss, and to further refine the theories describing mechanisms of this loss.Many factors contributing to drug loss are dictated by the physiology of the eye. Examples are the turn¬over of lacrimal fluid, ’the low holding capacity of the eye towards fluids, the act of blinking, reflex tearing and binding of drug with tear-proteins.One of the tools resorted to, in the last few decades, for the minimization of drug loss in the precorneal area is the addition of viscolizers to liquid ophthalmicpreparations.