Bioavailability of antiglaucoma drugs

The biodisponibility of antiglaucoma drugs, generally delivered in an aqueo us eye-drop solution depends on their capacity to cross the cornea. The str ucture of the cornea forms a barrier to strongly lipophilic substances and the continuous renewal of the lacrimal film creates a major obstacle, preve nting active substances from penetrating the eye. Active substances must th us be delivered in highly concentrated solutions. The systemic bioavailabil ity of antiglaucoma drugs taken orally, for example beta-blockers, is well known, their behavior after eye-drop administration remains poorly elucidat ed and highly dependent on individual susceptibility. We reviewed the liter ature on pilocarpine, beta-blockers, adrenergic drugs (dipivalyl-epinephrin e, apraclonidine, brimonidine), carbon anhydrase inhibitors (acetazolamide, dorzolamide).