Abstract
Purpose :
There is increasing interest in the use of therapeutic protein therapeutics to treat disorders of the ocular surface, due to the high receptor specificity of biologics, promising more effective therapy compared to small molecule pharmaceutics. Although these biological molecules vary in structure and properties, most of these have water solubility, potential to oxidize and susceptibility to proteolytic degradation. These attributes impart short half-lives and fleeting residence time on the ocular surface, compromising their therapeutic effect.
We have hypothesized that it is feasible to achieve sustained release of proteins such as immunoglobulins via a novel ocular insert NanoM™. We have developed a platform nanostructured ocular insert (NanoM™) that is placed into the lower conjunctival fornix in a dry form. Rapid absorption of water results in a “hydrogel-like” delivery system, molding itself to the underlying tissue. The molecular characteristics of the NanoM-Wafer are similar to ocular mucin, with porosity of the mesh matched to underlying mucin. This contributes to the biocompatibility and minimal immunogenicity at the target site.The delivery system is designed to be matched in flexural modulus to ocular conjunctival fornix and highly permeable to cell-signaling molecules, endogenous ions and oxygen. Compositionally, NanoM mesh wafer is highly hydrophilic, which renders the drug delivery biocompatible.
We hypothesized that IgG (240 Da. MW) could be encapsulated intact in ocular insert, with >80% integrity, measured by Size-Exclusion Chromatography. Additionally, we demonstrate sustained release of intact IgG from the wafer at 37°C, pH 7.4.
Methods :
Ocular inserts were fabricated by electrospinning of protein-containing solutions, on a rotating collector maintained at 18°C and 40%RH. Encapsulation of protein was determined by size-exclusion chromatography. IVRT was carried out on 8 mm inserts, at 37°C and pH 7.4 and receptor buffer retrieved at predetermined timepoints and analyzed by SEC.
Results :
Wafer inserts were 125 microns in thickness and 8 mm in diameter, a size that can comfortably fit under the lower eyelid. IgG encapsulation in wafer, was measured to be 19 mg/g, with >95% integrity. IgG was released in a sustained fashion over 4 days.
Conclusions :
A novel, biocompatible ocular insert was demonstrated as a feasible delivery system to administer high molecular weight proteins to the corneal surface.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.