A Novel Bioerodible Deep Scleral Lamellar Cyclosporine Implant for Uveitis

Abstract

Diffusion of CsA across the sclera from the episcleral space was not a feasible method of drug delivery to the equine eye. However, placing a deep scleral lamellar CsA implant adjacent to the suprachoroidal space was effective in achieving therapeutic ocular drug concentrations and controlling uveitis in horses with ERU.

Clinical experience and long-term outcome after subscleral insertion of a cyclosporine A drug delivery device in horses with immune-mediated keratitis

“…Those studies have shown that after implantation cyclosporine A can be found in therapeutic concentrations in various ocular tissues . One report by Gilger et al(2006) found no measurable concentration of cyclosporine A in the cornea after suprachoroidal implantation of the drug delivery device. Yet, the results of the study at hand indicate a certain effect against IMMK.…”

Delivery of therapeutics for deep-seated ocular conditions – status quo

“…[35] Additionally, using an ocular implant also allows for a sustained release of drug into the eye which can improve patient compliance as the frequency of dose is reduced and thus a reduced risk of toxicity. [35] Ocular implants can also prolong therapeutic duration at the site of action compared to other conventional drug delivery methods such as eye drops. [36] The use of ocular implants can overcome the limitation of topical eye drops where drug wastage is an immediate issue.…”

“…In situ gels are a drug delivery system which when administered in a liquid form phase shift into a gel or solid form once reaching the conjunctival cul-de-sac. [39] Despite typically being administered [1,4] ) 2 Ability to modify the rate of release of drug [1,4] 3 Ability to provide a stimuli-sensitive drug release mechanism [1,4] 1 Allow sustained release of drug [35,36] 2 Prolonged therapeutic duration at site of action [35,36] 3 Can overcome limitation of eye drops where drug wastage is an issue [35,36] 1 No blurred vision or irritation with administration [39,40] 2 Prolonged drug retention at desired tissue in the eye [39,41] 3 Decreased frequency of dosing [40,41] 1 Both hydrophilic or lipophilic drugs can be used [32] 2 Increase drug penetration across conjunctival and corneal epithelium [32] 3 Display ability to provide sustained released [32,46] 4 Decreased frequency of dosing [46] Cons 1 Low reproducibility [4,48] 2 Instability of the macromolecules during production stage [4,48] 3 Variable size distribution [4,48] 4 Expensive [4,48] 1 May increase intraocular pressure and induce local systemic adverse effects [38] 2 Inconvenient administration for patient [38] 3 Risk of tissue damage if administered incorrectly [38] 1 Lack of cell specificity [41] 2 Requires intravitreal administration due to poor penetration & specificity [40] 3 Expensive …”

Novel Drug Delivery Systems for Retinal Diseases

“…This increases the residency time of drug in the episcleral space and increases the concentration in the vitreous and retina compartments. A successful approach to improve the efficiency of transscleral drug delivery was reported in treating the blinding eye disease in horses, equine recurrent uveitis [52] . Here, subconjunctival implants releasing cyclosporine were placed in sub-Tenon's space, and the uveitis progressed unabated.…”