Development and physicochemical evaluation of a gelatine-based hydrogel tube for potential use in veterinary glaucoma implants

Piotr Szatkowski; Martyna Fröhlich; Oliwia Grałek; Magdalena Tabor; Edyta Molik; Zuzanna Flis

doi:10.2478/jvetres-2026-0015

Abstract

Introduction

Glaucoma is an eye disease in dogs and cats that increases intraocular pressure. There is no treatment method that is effective, safe and economical; however, scaffold drainage systems and hydrogels offer new therapeutic possibilities. The aim of this research was to develop a hydrogel implant for ophthalmic applications.

Material and Methods

Solutions at 5%, 10% and 15% concentrations of food-grade porcine gelatine and 15% and 16% concentrations of chemically purified gelatine with 19, 20, 21 mL or 25 mL of 2.5% glutaraldehyde as a crosslinking agent per 10 mL of distilled water were candidate formulations for the hydrogel. Visual and tactile assessments were made to choose the best candidate. The implant was a thin tube with an aluminium core and a Teflon foil mould. Curing was by immersion in ethanol. Ionic conductivity and compressive strength tests were performed on cylinder-shaped samples of the hydrogel. The best candidate hydrogel was tested calorimetrically for water content and its microstructure was examined for fluid transport capacity.

Results

The analyses confirmed the beneficial effect of alcohol on the structure. Hydrogels cured in ethanol were stiffer and more homogeneous and stable than those which were not, and the latter were eliminated. A hydrogel made with 1.8 g of 15% gelatine concentration, 19 mL of glutaraldehyde and 10 mL of distilled water was characterised by the highest resistance to standard compressive force. The highest ionic conductivity was obtained for the same sample. Thermal analysis showed that hydrogels stored in water contained significantly more weakly bound water (~0.53 g), whereas ethanol-conditioned hydrogels contained substantially less (~0.14 g), indicating a reduced water uptake and altered hydration profile due to alcohol conditioning. A hydrogel material based on gelatine crosslinked with glutaraldehyde was developed, from which a thin, small-diameter tube implant was made.

Conclusion

These studies have shown that the implant could potentially provide a solution for minimally invasive glaucoma treatment in small animals, but the testing phase must be continued.

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