Suprachoroidal pocket to collect drugs for treatment of ocular diseases

PurposeWe present the progressive improvement of a surgical procedure for suprachoroidal (sc) administration of drug, as an alternative route for drug administration to the posterior segment of the eye.Methods25 New Zealand albino rabbit eyes were used in the study. Fifty microliters volume of different increasing viscosity formulations were tested: balanced saline solution (BSS), 0.5% sodium hyaluronate solution (SH) and a formulation with patent to be register. Catheters of several gauges (25Gs, 27 Gs and 22 Gs) and different materials: metal cannula or flexible intravenous catheter were tested. Different architecture of the scleral-sc pocket were assayed: large quadrangular area with sutures, rectangular area with small port without stitch and conic with small entrance without stitch.ResultsFollowing items were analyzed: (1) Reflux post-administration: depending on the formulation; BSS and SH 0.5% (100%) versus Formulation (73.33%), on the surgical instrument for administration; 25G and 27G (100%) vs 22G (20%), and on different pocket architecture; quadrangular and rectangular (100%) vs conic pockets (73.33%). (2) Signs of ocular irritation: higher grades of hiperemia and secretion were observed in pockets with stitches (3) Ocular perforation: 1 eye in quadrangular pocket with stitch. (4) Surgical time: longer in sutured pockets.ConclusionsThe possibility of perform a sc pocket with a large conic area, small port and without stitches, permits us to use it as a receptacle for high viscosity formulations or implants for sustained drug delivery, avoiding the risks of intravitreal devices and allowing an easier removal of the implant in case of adverse reactions.