Recent advances in cyclosporine drug delivery: challenges and opportunities.

Cyclosporine has been established as a gold standard for its immunosuppressant action. Apart from this, the molecule is boon in treating broad spectrum of diseases like rheumatoid arthritis, psoriasis, and dry eye syndrome. The broad spectrum of cyclosporine demands efficient delivery systems by several routes. Neoral® and Sandimmune® are currently available formulations for oral route, whereas Restasis® is used for ocular delivery of cyclosporine. The available formulations serve the purpose only to a limited extent due to constraints like high molecular weight, low solubility, low permeability, bitter taste, and narrow therapeutic index of cyclosporine. Therefore, several novel formulations like microemulsion, self-emulsifying systems, nanoparticles, and microspheres were developed to overcome these constraints, exploring different routes like oral, ocular, and topical for cyclosporine. Additionally, iontophoresis and ultrasound-mediated delivery has also been studied to improve its poor permeability in topical delivery, whereas biodegradable implants were reported to increase the retention time in cornea and prolonged the release of cyclosporine by ocular route. Although these recent advances in cyclosporine delivery look promising, its clinical translation require in depth studies to deliver safe, efficacious, and stable formulation of cyclosporine. This review focuses on challenges of cyclosporine delivery and the recent advancements for overcoming the constraints.