Objective: In the present research work, aim was to prepare pH trigged in-situ ocular gel of Cetirizine Hydrochloride (CTZ) improve its local bioavailability at eye surface. Methods: CTZ prepared by pH-trigged method. In-situ a pH-sensitive gelling agent (Carbomer) with one-viscosity builder polymer (HPMC E4M). All formulation evaluated for appearance, pH, viscosity different capacity, % drug c...