Formulation and Evaluation of A Nanoparticle Laden in Situ Gel System for Enhancing the Ocular Delivery of Ciprofloxacin

The human eye can be a tricky issue for topical administration of the drugs due to its unique anatomical arrangements of surfacetissue and corneal impermeability. Topical instillation of drugs in the form of eye drops is the major and well-accepted route ofadministration for the treatment of varied eye disorders. Conventional ophthalmic drug delivery systems often lead to poorbioavailability and thus reduced therapeutic response. Several new preparations are developed to enhance the contact time of themedicament on the surface of the eye. Successful results have been obtained in the form of inserts and collagen shields. However,these preparations have also some disadvantages, such as poor patient compliance, particularly in the case of elderly patients. Theseproblems could be solved by using nanoparticles laden in situ gel-forming systems that exhibit phase transition from solution to gel.These nanoparticle in situ gel systems may be formulated as eye drops suitable for administration through instillation into the eye,which upon exposure to the eye, stimulated by various ocular physiological factors, converts to the gel phase. The advantage of thoseformulations is that unlike inserts and films they do not require complicated equipment for manufacture and that they are scalablewithout any difficulty. The objective of the present study was to prepare a pH-dependent nanoparticle-laden in situ gel system forCiprofloxacin, to prolong the release of the drug into the ocular compartment. No incompatibility was found between the drug andthe excipients. Nanoparticles were developed using the nanoprecipitation technique. Eudragit RL 100 was used as the polymer. Whilethe in situ gel solution was formulated using chitosan as polymer. The Ciprofloxacin nanoparticles were measured for particle sizeand the average particle size was ranged from 295.3-458.7 nm. Entrapment efficiency ranged from 13.83% to 6.29%. Nanoparticleladen in situ gels had the pH of the formulati