The CMHA-S platform is based on hyaluronic acid (HA), a naturally occurring polymer that is important in many physiological processes, including development, wound healing, tissue homeostasis, and joint lubrication. To create hydrogels, the HA is modified to create thiolated carboxymethyl HA (CMHA-S) that is then crosslinked together through the thiol groups. Some products are disulfide crosslinked while others utilize a crosslinker. The crosslinking slows degradation of the HA backbone and provides a matrix for incorporating therapeutic agents. Variations in the number of thiols per molecule, the molecular weight of the polymer, the concentration of the polymer, type of crosslinking, and incorporation of other molecules provides a highly versatile platform that can be tailored to a specific application. Products can be formatted as gels, films, sponges, or powders, and crosslinking can be done in situ.
Repeating molecular units of thiolated, cross-linked hyaluronic acid.
©Glenn Prestwich, Ph.D., University of Utah.
EyeGate’s first product from the CMHA-S platform is an eye drop formulation, the EyeGate Ocular Bandage Gel, that is applied topically. It provides a thin coating to the surface of the eye, serving as a protectant to facilitate and accelerate corneal re-epithelization. It is intended for the management of corneal epithelial defects and for the acceleration of re-epithelization of the ocular surface following surgery, injection, traumatic, and non-traumatic conditions.
Additionally, cross-linking allows the product’s viscosity to be modified to meet optimum ocular needs. The increased viscosity and non-covalent muco-adhesive interfacial forces improve residence time in the tear film, thus providing a coating that aids and promotes re-epithelization of the ocular surface via physical protection. The EyeGate Ocular Bandage provides significant mechanical improvement over non-cross-linked hyaluronic acid products and other hydrogels by forming a degradation-resistant coating. Pilot preclinical studies suggest that this chemical modification will prolong dwell time on the ocular surface, thus providing a smooth continuous clear barrier without blur, minimizing mechanical lid friction, and reducing repeat injury, which can mechanically protect the ocular surface and accelerate corneal re-epithelization (Burdick and Prestwich 2011).
The Ocular Bandage is presently available commercially as a veterinary device, manufactured by SentrX Animal Care and sold in the U.S. by Bayer Animal Health as Remend® Corneal Repair, indicated for use in the management of superficial corneal ulcers. The product has been used for 5 years in dogs, cats and horses, with an excellent safely. The composition of the veterinary product is identical to that of the EyeGate Ocular Bandage Gel.