Abstract
Purpose: :
To evaluate the pre-clinical safety and efficacy of a next-generation synthetic hydrogel tissue sealant (ReSure Sealant) for clear corneal wounds.
Methods: :
ReSure Sealant is composed of polyethylene glycol (PEG), an amine crosslinker, and a diluent solution. The components are mixed to initiate a crosslinking reaction to form a hydrogel in situ on the ocular surface. In the days following application of the device, the ReSure Sealant resorbs via hydrolysis and is sloughed off in the tears. Initial safety testing was conducted in rabbits for evaluation of ISO biocompatibility, intraocular toxicity, and device persistence. Further safety and efficacy studies were conducted in porcine models for sealing clear corneal incisions, removability of the device, and ocular irritation via histology.
Results: :
ISO10993 biocompatibility testing demonstrated the hydrogel to be non-cytotoxic, non-sensitizing, non-ocular irritating, and non-toxic via acute systemic toxicity. Intraocular toxicity over 14 days showed no evidence of macroscopic (slit lamp exam, intraocular pressure measurements) or microscopic ocular irritation or toxicity after the sealant was injected into the anterior chamber of rabbits. Also in a rabbit model, multiple sealant doses were evaluated on days 1, 3, 7 and 14 for persistence and ocular irritation. At day 3, no sealant was present on the treated corneal incisions and re-epithelization was confirmed via fluorescein staining. The sealant was not associated with any macroscopic or microscopic ocular irritation or delayed healing vs incision only controls. In the porcine model, efficacy of the sealant was evaluated in a parallel-arm study versus 10-0 suture closure on 2.5mm corneal incisions. After randomization, the incisions were challenged using a calibrated force gauge to apply one ounce of force 0.5 mm away from the incision immediately and 24 hours post-application. The sealant demonstrated non-inferiority for preventing fluid egress when compared to sutures. The sealant was present on the incision for a minimum of 24 hours and sloughed off by day 2 when the incisions had re-epithelialized. In a separate swine study, the removability of the hydrogel from a corneal incision using a Weck-cel sponge & forceps was evaluated ≥ 30 seconds after application. Histology was taken immediately post-removal of the device and at day 7. Examination of histopathologic data demonstrated acceptable healing with no ocular irritation.
Conclusions: :
The safety and efficacy of the hydrogel tissue sealant for ocular applications was demonstrated via a number of animal studies with documented biocompatibility, while exhibiting the hydrogel’s ability to seal corneal incisions.
Keywords: wound healing • cornea: basic science • refractive surgery