Formulation Development and Optimization of Phase-Transition W/O Microemulsion In Situ Gelling System for Ocular Delivery of Timolol Maleate in the Treatment of Glaucoma

The present investigation is aimed to prepare and e luate the micro emulsion -based phase transition ocular system for deli\ cry of Timolol maleate in the treatment of glaucoma. Timolol malcate is used in the first line of treatment in open -angle glaucoma belonging to BC'S class -I having good solubility and permeability. The rapid precomeal elimination of con \ cntional formulation containing class I drugs exhibits poor therapeutic effect and bioa \ ailability. So. microcmulsion (ME) based phase transition systems were formulated and characterized. ME based phase transition system 'vas formulated using Ethyl oleatc as oil and CremophorEL as a surfactant. Span 2() as Co -surfactant. and Sorbic acid as a preser\ ati \ e. These systems undergo a phase transition from water-in -oil (w/o) MI to liquid crystalline (LC) state and to coarse emulsion (EM) with a change in viscosity depending on dilution with tear fluid A:: water content. Prepared microcmulsions were characterized for average globule size. zeta potential. pH. conductance. in-viu-o gelling capacity. The optimized fo ulation was selected based on desirable attributes and \\ as further characterized and compared with marketed ophthalmic gel -forming marketed solution of Timolol malcate (TIMOPTIC-XE'). All the results of the characterization were satisfactory. The optimized water -in -oil ( \\ /0) microemulsion shoved droplet size 23,47 nm. the zeta potential of 0.253mV. pH of 7.2. the conductance of 0.25mS. and drug content of 90.64%. The phase transition wio ME provides the fluidity for installation with its viscosity being increased due to phase transition after application increasing ocular retention \\ hilc retaining the therapeutic efficiency. The in- vino drug release and lOP reduction \\ ith optimized formulation were found comparable and less fluctuating compared to marketed formulation. Optimized fo ulation was found stable during the accelerated stability study. The developed phase transition \\ /o 'dl fo ulation would be able to offer benefits. such as increased residence time, prolonged drug release. reduction in dosing frequency, and thereby it will improve patient compliance.