A new eyedrop formulation of spirolactone helps corneal wound healing in rats
Corneal wound healing problems can result in “corneal opacity,” the third most common cause of impaired vision and blindness. This condition occurs when the cornea, the clear and transparent front part of the eye, becomes cloudy or opaque, hindering the passage of light into the eye and causing vision impairment or blindness.
Aligned with Restore Vision’s ambition to repurpose existing drugs to develop new treatments for rare eye diseases, our team at INSERM conducted a scientific study to test the effects of a newly formulated Spirolactone eye drop on the healing of corneal wounds in rats.
The study
The study started with the development of a new eye drop formulation using Spironolactone (SPL), a well-known antimineralocorticoid drug with proven anti-inflammatory properties that help corneal repair. Researchers combined SPL with hydroxypropyl-gamma-cyclodextrin (HP-γ-CD) to create a safe and effective medical-grade eye drop, specifically tailored for the treatment of corneal wounds. To achieve this, researchers collaborated with the pharmaceutic industry and developed the formulation following good manufacturing practices to ensure a faster translation to clinic.
Initially, researchers evaluated the safety of the eye drops. They administered the drops once a day to some rats and three times a day to others, for a consecutive week. The corneas were then examined using histology and immunofluorescence techniques to ensure that their use had been safe and did not harm the integrity of the corneal barrier.
Next, researchers evaluated if SPL eye drops could improve corneal wound healing in rats. Researchers gently removed a small piece of the cornea, treating some of the rat eyes with SPL eye drops and others with a placebo. They monitored the healing process using fluorescent dye and optical coherence tomography (OCT) to detect any swelling. They also used advanced imaging methods (immunofluorescence) to assess changes in corneal structure, inflammation, and nerve regeneration.
The results
Researchers found that the SPL eye drop formulation was safe and well-tolerated, showing no harmful effects or changes in the structure and composition of the rat’s cornea after the 7-day experiment. Additionally, SPL eye drops accelerated corneal wound healing by reducing swelling and inflammation and promoting nerve regeneration and epithelial integrity. Another advantage was that the drops remained effective for up to 9 months when stored at 4°C.
Next steps
The initial findings from this Restore Vision’s study offer promising indications that SPL eyedrops might have potential benefits in cases of impaired corneal wound healing. Researchers are currently conducting a pharmaceutical kinectic study to assess how the medication behaves on the surface of the eye. Further studies will also be needed to optimize the formulation before it can be tested in patients through clinical trials.
Through the repurposing of well-known drugs, such as Spirolactone, alongside familiar excipients, Restore Vision is focused on accelerating the translation of findings from the lab to the clinic.