In Situ Gels Triggered by Temperature for Ocular Delivery of Dexamethasone and Dexamethasone/ SBE-β-CD Complex

This research aims to increase the solubility of Dexamethasone (Dex) using cyclodextrin and develop a temperature-triggered in situ gelling system for the ocular application. The solubility of Dex was increased with SBE-β-CD. Dex-SBE-β-CD inclusion complex was prepared with kneading and freeze-drying method. Structural characterization was carried out using DSC and FT-IR. When in situ gel formulations were prepared, Pluronic F127 (PF127), a thermosensitive polymer, and Chitosan (CH), a natural, biodegradable, and mucoadhesive hydrophilic polymer, were used together. When the solubility diagrams of the drug-cyclodextrin inclusion complex were examined, it was determined that SBE-β CD showed a linear increase, and AL-type diagram was selected in consequence. The formulations were produced using different amounts of PF127 and a fixed ratio of CH. In situ gels were evaluated for clarity, pH, gelation temperature, and rheological behaviors and selected one formulation. It was established that the formulations were clear, their pH was 6, their gelation temperature decreased with increasing PF127, and was between 22-34 °C. For the selected formulation, 0.1% Dex and Dex/ SBE-β-CD were transferred to in situ gelling systems. As a result of in vitro release studies, it was observed that the release of the Dex/SBE-β-CD inclusion complex containing BRN formulation showed a higher burst effect than the other and was released for 6 hours. The results exhibited that the combination of PF127 and CH has potential as an in situ gelling systems for ocular delivery of Dex and Dex/ SBE-β-CD. © 2022 Marmara University Press.