| Abstract (english) | A major problem in ocular therapeutics is the attainment of an optimal
drug concentration at the site of actions. Poor bioavailability of drugs from
ocular dosage form is mainly due to the precorneal loss factors which include
tear dynamics, non-productive absorption, transient residence time in cul-desac, and the relative impermeability of the corneal epithelial membrane. Current trends in ocular therapeutics and drug delivery suggest that the existing
dosage forms will be replaced by novel drug delivery systems that offer improved biopharmaceutical properties. Various approaches, like viscosity enhancement, use of penetration enhancers, polymers for the preparation of hydrogels, in situ gelling systems, mucoadhesive, particulate drug delivery,
vesicular drug delivery, and other controlled systems, like ocular inserts, are
being explored. Nevertheless, about 70% of prescriptions for the eye medications are for conventional eye drops. This is due factors including expense, difficulty in bulk manufacture, patient compliance, efficacy and stability. |
