Effect of intraocular pressure (IOP) and choroidal circulation on controlled episcleral drug delivery to retina/vitreous.

Transscleral drug delivery may become a safe alternative to the intravitreal injection for chronic retinal diseases such as age-related macular degeneration or diabetic macular edema. However, the drug delivered onto the sclera subjects to vigorous clearance by episcleral and choroidal circulation; in addition, the penetration from episclera to retina needs to overcome counter-directional ocular fluid current driven by intraocular pressure (IOP) as well as unfavorable drug disposition exerted by drug transporters before the drug reach retina. It is imperative to understand these processes and quantitate their influence for efficient designing of a sustained formulation or device to achieve efficient transscleral drug delivery.

Episcleral drug film for better-targeted ocular drug delivery and controlled release using multilayered poly-ε-caprolactone (PCL).

Unlabelled: Triamcinolone acetonide (TA) and poly-ε-caprolactone (PCL) were engineered into a micro drug film for episcleral application to better manage chronic vitreoretinal diseases such as proliferative vitreoretinopathy (PVR). Compared to an intravitreal drug injection, this drug film is much safer without breaking into ocular barriers. Compared to a traditional subtenon injection, this drug film demonstrated superior therapeutic duration, better drug bioavailability in the choroid and retina, and better-targeted drug delivery ability.

[Characteristic of ocular safety profile of triamcinolone made in China].

Objective: To characterize the safety profile of triamcinolone acetonide made in China (Transton) and triamcinolone acetonide acetate (Tongyong) for their ocular application.

Methods: Experimental study. In vitro cell viability assay was performed on 3 types of human ocular cells to evaluate the cytotoxicity of the simulated vitreal concentrations (from a 1:15 dilution as if injected into 1.

Sustained release of triamcinolone acetonide from an episcleral plaque of multilayered poly-ε-caprolactone matrix.

A subtenon injection of triamcinolone acetonide (TA) is a widely used treatment modality for various chorio-retinal diseases. Although it is less invasive than intravitreal injection, it can produce dose-associated ocular complications and has the disadvantages associated with systemic TA exposure. In this study we have developed and evaluated an episcleral film consisting of TA and poly-ε-caprolactone (PCL).

The effect of ocular pigmentation on transscleral delivery of triamcinolone acetonide.

Purpose: To determine the capacity and kinetics of the binding between triamcinolone acetonide (TA) and the ocular pigment for a better understanding of the transscleral delivery.

Methods: In the in vitro study, natural melanin (sepia officinalis, Sigma-Aldrich) was incubated at 37°C with different concentrations of TA and the binding capacity/binding affinity was measured. The TA releasing profile from the melanin was also studied through repeated incubation of TA-melanin in fresh phosphate-buffed saline.