Enhancement of bioavailability of a poorly soluble drug

Abstract

Glaucoma is a retinal neuropathic disease considered as the silent thief of sight. It is the leading cause of irreversible blindness worldwide and is ranked number two among all blindness causing diseases. The high intraocular pressure (IOP) is the major risk factor for induction of glaucoma. Acetazolamide (ACZ) is a highly effective systemic drug used in management of both types of glaucoma (open and closed angle). It belongs to the carbonic anhydrase inhibitors (CAIs) class known to decrease the aqueous humor production from the ciliary body lowering IOP. Unfortunately, ACZ is available only as oral tablets, capsules and intravenous injection. Its administration in large doses is usually accompanied by several side effects including metabolic, respiratory acidosis and diuresis therefore, patients tend to be incompliant and often discontinue treatment. Ocular administration of ACZ could achieve a great advance in glaucoma treatment excluding several side effects besides enhancing patient compliance. Nevertheless, ocular ACZ delivery is constrained by its low aqueous solubility and permeability being categorized as class IV according to BCS, in addition to the ocular biological barriers that should be surmounted.