Topical Insulin Eye Drops: Stability and Safety of Two Compounded Formulations for Treating Persistent Corneal...

Area of Science:

• Ophthalmology
• Pharmaceutics
• Cell Biology

Background:

• Persistent corneal epithelial defects (PEDCs) are a challenging clinical condition.
• Current treatments for PEDCs have limitations, necessitating novel therapeutic approaches.

Purpose of the Study:

• To develop and characterize compounded insulin eye drops for potential use in treating PEDCs.
• To evaluate the physicochemical properties, stability, and in vitro/in vivo safety and efficacy of these formulations.

Main Methods:

• Insulin eye drops (1 IU/mL) were prepared using subcutaneous insulin diluted in normal saline or artificial tears.
• Formulations underwent physicochemical characterization (isotonicity, pH, surface tension, viscosity) and stability testing (28 days, refrigeration).
• In vitro testing included cell tolerance assays, and preliminary human studies assessed safety and efficacy for PEDCs.

Main Results:

• Both formulations were isotonic with neutral pH, but saline-based drops had lower viscosity.
• Saline-based insulin eye drops maintained potency (90-110%) for 28 days under refrigeration, unlike artificial tear-based ones.
• In vitro, both were well-tolerated, with saline showing superior cell tolerance. Human data indicated efficacy and safety for PEDCs.

Conclusions:

• Compounded insulin eye drops in normal saline solution demonstrate favorable physicochemical properties and excellent stability.
• The saline-based formulation exhibits superior in vitro cell tolerance and shows promise as a safe and effective treatment for persistent corneal epithelial defects.
• Insulin eye drops represent a potential emergent therapy for challenging corneal conditions.