Chapter 5 - Polymeric hydrogels for contact lens-based ophthalmic drug delivery systems

Abstract

The field of ocular drug delivery is one of the most interesting and challenging routes for researchers over the past 10–20 years. It is difficult to obtain the correct therapeutic concentration of a drug at the required site, due to the physiological and anatomical constraints. To achieve effective ophthalmic therapy, an adequate amount of drug must be delivered and maintained within the eye region. A contact lens is a novel dosage form; curved in shape and made up of polymers that are designed to cover the cornea and which cling to the surface of the eye owing to surface tension. The interest in formulation of contact lenses has significantly increased in the last decade, as several new techniques have been developed for designing contact lenses for extended drug delivery. The use of a contact lens helps increase precorneal residence time to a longer duration and exhibit its maximum biological action. Additionally, it can provide a uniform release profile, compared to the pulsatile delivery with eye drops. This can potentially result in improved therapeutic outcomes which significantly improve the compliance. In this chapter, we describe the literature on ocular delivery using contact lenses, their classification and manufacturing process, and recent advances on drug delivery techniques using such lenses.