Formulation and Characterization of Ophthalmic in Situ Gel Forming Solution of Timolol Maleate for Glaucoma

This study comprehensively investigates the physicochemical properties and performance of ophthalmic formulations containing timolol maleate with different polymers. Fourier-transform infrared (FTIR) spectroscopy revealed distinct spectral changes, indicating interactions between timolol maleate and Hydroxyethyl Cellulose (HEC), Xanthan gum, and Gellan gum. Clarity assessments confirmed transparency against white and black backgrounds. pH measurements ensured physiological compatibility (HEC: pH 6.90, Xanthan gum: pH 6.97, Gellan gum: pH 6.98). Evaluation of gelling capacity and strength highlighted Xanthan gum's superiority (Xanthan gum: 180 Pa, Gellan gum: 153 Pa). Viscosity studies demonstrated suitability for ocular use, with pre-gelling values of HEC: 100.11 cps, Xanthan gum: 112.55 cps, Gellan gum: 110.42 cps, and post-gelling values of HEC: 100.01 cps, Xanthan gum: 256.22 cps, Gellan gum: 206.21 cps. Osmolality aligned with ophthalmic norms (HEC: 272 mOsm/kg, Xanthan gum: 290 mOsm/kg, Gellan gum: 285 mOsm/kg). In vitro drug release profiles varied, with Xanthan gum showing sustained release (95.01% over 8 hours). Rabbit eye irritation studies confirmed safety. Stability assessments over three months validated consistent attributes, supporting their potential as effective ophthalmic formulations.