89FORMULATION AND EVALUATION OF OCULAR IN-SITU GELLING SYSTEM OF TIMOLOL MALEATEThe present investigation highlights the formulation and evaluation of ocular in-situ gelling system of Timolol maleate. The formulation of in-situ gelling system of Timolol maleate has been prepared by ion -activation mechanistic approaches. In the present scenario considerable interest has been developed on in -situ gelling system because, poor bioavailability of ophthalmic solutions caused by dilution and drainage from the eye can be overcome by using in -situ-forming ophthalmic drug delivery systems prepared from polymers that exhibit reversible liquid-gel phase transition. The aqueous solution of sodium alginate can gel in the eye, without the addition of external calcium ions or other bivalent/polyvalent ca tions but the gelation not extended. The gelation can be extended with the help of HPMC and SCMC. All developed formulations were evaluated for appearance, pH, rheological studies, in-vitro gelation studies and drug content. All the prepared formulations were carried out for in-vitro drug release studies and distinguishable differences were observed. The in-vitro drug release studies were performed all the formulations shows the controlled release pattern of drug up to 8 h. All prepared formulations exhibit controlled release with zero order drug release followed by non-Fickian mechanism.satheeshbcp@gmail.comResearch522015 In-situ gel,Timolol maleate,In-vitro gelation,Zero order,Non-FickiaE. Satheesh Kumar,B. Gopala KrishnaAcharya Nagarjuna university, Nagarjuna Nagar, Guntur-522 510, Andhra Pradesh, India,R R College of Pharmacy, Chikkabanavara, Bangalore – 560 090, Karnataka, India