Ophtalmic Preparations

Eye drops are one of the oldest forms of galenic medicine. As far back as the Pharaonic era, Egyptian physicians used eye drops to treat eye infections, which were very common at the time. Originally, eye drops were small rat-tail-shaped sticks made from active ingredients and glue (from the Greek kollurion, from kolla: glue and oura: tail). These sticks were diluted in a liquid at the time of use. Eye drops remain the main galenic form used for ocular administration, but many other forms can also be used. Ophthalmic preparations are defined in the European Pharmacopoeia as sterile liquid, semi-solid or solid preparations intended for application to the eyeball and/or conjunctiva, or for insertion into the conjunctival cul-de-sac.

Active ingredients administered orally or systemically do not reach the vitreous and aqueous humours of the eye, or only to a limited extent, due to the barriers that limit penetration into the eyeball. They are therefore most often administered topically, on the surface of the eye, for local action. For the treatment of deep-seated disorders of the vitreous humor or retina, the intra-ocular route can be used, and new galenic developments aim to improve penetration.

The main pharmacological classes used by the ophthalmic route are anti-infectives, antiglaucoma agents, anti-inflammatories, immunosuppressants, anti-allergics, mydriatics and diagnostic or lacrimal replacement products.

The aim of this article is to present the current state of knowledge of galenic forms used in ophthalmology. The basic principles of formulation must take account of the characteristics associated with this route of administration, such as tolerance and ocular residence time. In recent years, galenic development has focused on innovative forms that are more complex to formulate and produce.