FORMULATION AND EVALUATION OF SOME SELECTED TIMOLOL MALEATE OPHTHALMIC PREPARATIONS

The purpose of this study was to prepare and evaluate certain Timolol maleate (TM) polymeric formulations including viscous solutions, hydrogels and in-situ gels aiming to improve its ocular bioavailability and decrease its side effects. In this study, Chitosan (CS), hydroxyehtylcellulose (HEC), hydroxypropylmethylcellulose (HPMC) and sodium carboxymethylcellulose (NaCMC) were used to prepare TM viscous solutions and hydrogels. In-situ gels of Gelrite and Pluronic F-127 (Pl F-127) were prepared at different concentrations. Mucoadhesives namely CS or HEC were incorporated to Pl F-127 to produce mucoadhesive/insitu gel. The prepared formulations were evaluated for their in-vitro drug release, viscosity, gelation temperature and mucoadhesive force. The selected TM formulations were tested for their effect on intraocular pressure (IOP) and systemic side effects based on blood pressure (BP), heart rate (HR) and respiration rate (RR). The results revealed that, TM in situ-gels F25 (containing Pl F-127 20% and CS 1.5% w/w) and F31(containing Gelrite 0.6% w/w) showed reasonable in-vitro results, and a marked IOP lowering activity without systemic side effects compared to TM marketed eye drops.