The eye is a specialized sensory organ that is relatively secluded from systemic access by the blood-retinal, blood-aqueous and blood-vitreous barriers [1].Most of the ocular diseases are treated with topical application of eyedrops.Topical delivery in the lower cul-de-sac is the most common method for application. The site of action for most ophthalmic drugs is located in the inner eye. 2.1. Limiting Factors for the Resorption to the EyeExternal eye structures are readily accessible for topical application, but several factors limit the entry of drugs to the eye structure from the tear film. The following main factors may be responsible for this limitation: (a) the corneal barrier; (b) drug binding to proteins in the tear fluid; (c) nonproductive absorption to the conjunctiva of the eye, or (d) rapid loss of the instilled solution from the precorneal area, also by nasolacrimal drainage. 2.2.Absorption takes place through the cornea, the conjunctival tissue and the nasal mucosa.The main factors influencing drug distribution and absorption are summarized in figure 1.The diffusion of an antimicrobial agent across the corneal barrier is influenced by the concentration of the drug at the epithelial surface (diffusion along the concentration gradient), the degree to which the drug is soluble in both aqueous and lipid phases, and the amount of nonionized drug (more diffusible) compared to the ionized drug (less diffusible) at a physiological pH of 7.4. The epithelium, which is lipoidal in nature and has tight junctions, serves as a barrier to diffusion of drugs from the tears into the eye, and diffusion of drugs being amphoteric in nature is facilitated [3,4].