Development and Evaluation of a Diclofenac‐Loaded Thermogel for Topical Treatment of Corneal Alkali Burns

Abstract

Corneal alkali burns have become a frequent and urgent issue in ophthalmology, but current treatments are limited. To address this, a diclofenac‐loaded thermogel with anti‐inflammatory agents is developed to target inflammation and improve drug delivery for corneal alkali burns. Thermogels are prepared by dissolving methylcellulose (MC) and hydroxypropyl methylcellulose (HPMC) in phosphate‐buffered saline (PBS), adding diclofenac (DF), and storing the solution at 4 °C. The thermogel's temperature‐sensitive behavior and injectability at 35 °C are assessed. Freeze‐dried thermogels are examined using scanning electron microscopy. Rheological properties, swelling behavior, and in vitro release studies are conducted. In vitro and in vivo biocompatibility tests are performed. A corneal alkali burn model is established in rats, and different treatments are administered for 7 days. Eyeballs are collected for histological and molecular analysis. The thermogel formulation formed a stable gel at 35 °C and continuously released DF for 7 days. In vitro and in vivo tests confirmed the thermogels' excellent biocompatibility. The released DF promotes the expression of the anti‐inflammatory cytokine interleukin‐10 (IL‐10) and inhibits the expression of pro‐inflammatory factors TNF‐α and vascular endothelial growth factor (VEGF). This novel DF/thermogel offers an efficient, topical, and cost‐effective approach with significant potential for treating corneal alkali burns.