PLDLA/TPU Matrix Enriched with Cyclosporine A as a Therapeutic Platform for Immune-Mediated Keratitis (IMMK) in Horses.

The purpose of this study was to describe the use of PLDLA/TPU matrix enriched with cyclosporine A (CsA) as a therapeutic platform in horses with immune-mediated keratitis (IMMK) with an in vitro evaluation CsA release and degradation of the blend as well as determination of the safety and efficacy of that platform used in the animal model. The kinetics of the CsA release from matrices constructed of thermoplastic polyurethane (TPU) polymer and a copolymer of L-lactide with DL-lactide (PLDLA) (80:20) in the TPU (10%) and a PLDL (90%) polymer blend were studied. Moreover, we used the STF (Simulated Tear Fluid) at 37 °C as a biological environment to assess the CsA release and its degradation. Additionally, the platform described above was injected subconjunctival in the dorsolateral quadrant of the globe after standing sedation of horses with diagnosed superficial and mid-stromal IMMK. The obtained results indicated that the CsA release rate in the fifth week of the study increased significantly by the value of 0.3% compared to previous weeks. In all of the cases, the TPU/PLA doped with 12 mg of the CsA platform effectively reduced the clinical symptoms of keratitis, leading to the complete remission of the corneal opacity and infiltration four weeks post-injection. The results from this study showed that the PLDLA/TPU matrix enriched with the CsA platform was well tolerated by the equine model and effective in treating superficial and mid-stromal IMMK.

Cyclosporine A Delivery Platform for Veterinary Ophthalmology-A New Concept for Advanced Ophthalmology.

Cyclosporine A (CsA) is a selective and reversible immunosuppressant agent that is widely used as a medication for a wide spectrum of diseases in humans such as graft versus host disease, non-infectious uveitis, rheumatoid arthritis, psoriasis, and atopic dermatitis. Furthermore, the CsA is used to treat keratoconjunctivitis sicca, chronic superficial keratitis, immune-mediated keratitis and equine recurrent uveitis in animals. The selective activity of Cyclosporine A (CsA) was demonstrated to be an immunomodulation characteristic of T-lymphocyte proliferation and inhibits cytokine gene expression. Moreover, the lipophilic characteristics with poor bioavailability and low solubility in water, besides the side effects, force the need to develop new formulations and devices that will provide adequate penetration into the anterior and posterior segments of the eye. This review aims to summarize the effectiveness and safety of cyclosporine A delivery platforms in veterinary ophthalmology.