Gourav Rajoria

  Eye, which is the most vital organ of the body suffer from various eye problems like glaucoma, endopthalmitis, dry eye syndrome, trachoma, keratitis, conjunctivitis etc. Most ocular diseases are treated by topical drug application in the form of solutions, suspensions and ointment. These conventional dosage forms suffer from the problems of poor ocular bioavailability because of dilution and rapid drainage. Prolonged drug delivery can be achieved  by various new dosage forms like in-situ gel, collagen shield, minidisc, ocular film, ocusert, nanosuspension, nanoparticulate system, liposomes, niosomes, dendrimers, ocular iontophoresis etc. The most successful of these is the in-situ forming ophthalmic drug delivery systems prepared from polymers that exhibit reversible liquid-gel phase transition .The aim of this article is to present a concise review of in-situ gelling system to overcome all above problems. This review also summarizes various temperature, pH, and ion induced in-situ forming polymeric systems used to achieve prolonged contact time of drugs with the cornea and increase their bioavailability.

The traditional formulations like solution, suspension or emulsion suffer from certain limitations like high dose and low bioavailability, first pass metabolism, intolerance, instability and also exhibit fluctuations in plasma drug levels and do not provide sustained effect, therefore, there is a need for some novel carriers which could attain ideal requirements of a drug delivery system. Nanoparticles delivery system has been proved nearly ideal one. Nanoparticles are, a type of colloidal drug carrier system comprising particles with diameter of nano-metric range. The rapid development of nanotechnology and nano-materials has led to a need for nanoparticle surface modification for a variety of applications. The surface can be tailored to specific physical, optical, electronic, chemical, and biomedical properties by coating a thin film of material on the surface of the nanoparticles. The coating or encapsulation of nanoparticles has been found to be of particular interest for the controlled release of drugs, genes and other bioactive agents. Controlled release systems provide the benefits of protection from rapid degradation, targeting delivery, control of the release rate and prolonged duration of bioactive agents. This article have a keen emphasize on the techniques used for the formulation of nanoparticles and their coating too along with associated cautions and significance related to special applications which reveals a better way to choose the suitable and efficacious technique to obtain a nano-sized formulation. It also reveals the need of regulatory framework for handling of nanoparticles.