Microemulsion Eyedrop for Delivery of a PPARα Agonist To Improve Diabetic Keratopathy Corneal Wound Healing
Ehsan Kaffash1, Wentao Liang2, Rudra Pangeni1,3
1Department of Pharmaceutics, Virginia Commonwealth University, Richmond, Virginia23298, United States.
Abstract:
Diabetic keratopathy (DK) is characterized by delayed corneal wound healing in diabetes, and recent studies have linked this defect to impaired mitochondrial respiration and reduced peroxisome proliferator-activated receptor-α (PPARα) signaling in the corneal epithelium. The PPARα agonist fenofibrate (Feno) has shown therapeutic potential in diabetic corneal disease, but prior topical and oral approaches still face formulation and translational limitations. In this study, we developed a Feno-loaded microemulsion (Feno microemulsion) eyedrop to improve drug solubility, precorneal residence, and ocular bioavailability of Feno for the treatment of DK. Potential excipients were first screened in primary human corneal epithelial cells (HCECs) to identify components that were well tolerated and did not interfere with epithelial migration. Using the optimized excipients, a stable oil-in-water microemulsion was formulated with high drug loading, nanosized droplets, favorable shear-thinning rheology, and excellent physicochemical stability over 12 months. The optimized formulation showed good ocular tolerability, prolonged ocular surface retention, and sustained drug exposure in tear fluid and ocular tissues with minimal systemic absorption. Under high-glucose and oxidative stress conditions, Feno microemulsion enhanced HCEC migration, restored mitochondrial respiration and ATP production, and increased the expression of PPARα-associated mitochondrial markers. In vivo, topical Feno microemulsion significantly accelerated corneal epithelial wound healing in both streptozotocin-induced (type 1 diabetic) and db/db (type 2 diabetic) mouse models and also improved early-stage healing in nondiabetic controls. Overall, these findings identify Feno microemulsion as a safe and effective topical platform for DK and support its therapeutic benefit through preservation of corneal mitochondrial function and promotion of epithelial wound healing.
