DEVELOPMENT AND CHARACTERIZATION OF AN OCULAR IN SITU GEL FORMULATION CONTAINING INDOMETHACIN

Objective: This study aims to formulate in-situ gel formulations for extended duration of indomethacin (INDO) on the corneal surface which will improve the ocular bioavailability for sufficial treatment of ocular inflammatory disorders. Material and Method: Formulations were prepared by cold method. Briefly polymers were dissolved in cold ultrapure water and INDO was added to the solutions. A modified UV method was used. DSC, FT-IR and 1H-NMR analyses were used for the determination of structural properties of INDO and excipients. The formulations were characterized through measurements of gelation temperature and gelation time, determination of pH, rheological assessments, and in vitro drug release experiments conducted in PBS (pH 7.4) at 34 ± 2°C. Result and Discussion: According to the gelation temperature and gelation time analyses optimum formulation which contained %17 (w/w) Poloxamer 407 (P407) was selected for further studies. Evidence of drug–polymer compatibility was obtained through DSC, FT-IR, and ¹H-NMR studies. INDO was loaded to the formulation at 0.1% (w/w). pH of the formulation was 5.29±0.00 and considering the ocular tolerability no adjustment was required. The rheological analyses revealed the gel transition point at 34°C±2°C. In vitro release analyses revealed that even after 6 hours only 30% of the INDO was released from the formulations showing the extended release of the active agent with the help of transition of the eye drops to the solidified gel structure. These results support the notion that ocular bioavailability will be enhanced with P407 based in-situ gels considering extended retention time of INDO on the corneal surface.