[Topical ophthalmic drugs]

Although satisfactory therapeutic results are obtained with usual topical opthalmic drugs, they present some inconveniences. Particularly, their biodisponibility is often poor, requiring the use of relatively important doses, and repeated applications. In order to avoid these difficulties, different systems more or less sophisticated, such as soluble inserts, impregnated lenses, liposomes or implantable pumps, have been conceived for topical application. However, although these systems seem to present certain advantages, none of them, commercialized or not, have been quite satisfactory.