Injectable nanogels to improve triamcinolone acetonide delivery and toxicity on the treatment of eye diseases

Triamcinolone acetonide (TA) is a corticosteroid, and widely used in the treatment of eye diseases such as macular edema, proliferative vitreoretinopathy, and chronic uveitis. It's also used in diseases such as osteoarthritis and rheumatoid arthritis. Despite the width of its usage, it has toxicity in the eye. Nanogels are advantageous in applying toxic and low bioavailability drugs thanks to their swelling ability and stability. In the presented study, to minimize the disadvantages of TA, and to reach the drug into the back segment of the eye, TA-loaded chitosan (CS) nanogel (CS-TA Nanogel) has been prepared, and in vitro characterized. CS-TA nanogels were prepared by ionic gelation and characterized by SEM, FTIR, and TGA. Drug release profile, and in vitro cytotoxicity was determined to evaluate the efficacy of nanogels for intravitreal eye applications. DNA damage, and oxidative stress caused by nanogels in eye endothelial cells were investigated. CS and CS-TA nanogels were synthesized in the sizes range 200-300 nm with an overall positive charge surface. The loading efficiency of TA on nanogels was determined as 50%. Cells exposed to 250 µg/ml free TA showed 74% viability, while this rate was 90% in cells exposed to CS-TA nanogels. 8-OHdG levels were determined as 54.93 ± 1.118 ng/mL in control cells and 92.47 ± 0.852 ng/mL in cells exposed to 250 µg/ml TA. TA both induces oxidative stress and causes DNA damage in HRMEC cells. However, administration of TA with carrier increased cell viability, total antioxidant capacity, and reduced oxidative DNA damage.