Development of brimonidine and crocetin loaded hydrogels

Background and Aim: Crocetin is a naturally occurring substance with high antioxidant properties derived from the saffron plant. The aim of this study was to create a two-component, naturally occurring, hydrogel-based eye drop by combining brimonidine tartrate, a selective α-2 adrenergic receptor antagonist commonly used in glaucoma treatments, with crocetin. Materials and Methods: UV analyses were performed on brimonidine tartrate and crocetin separately and together to determine the wavelengths at which they absorb light and to investigate whether they interfere with each other when combined. Solubility studies were conducted for brimonidine tartrate and crocetin to identify the solvents to be used in the formulation. The amount of crocetin required to provide antioxidant properties in the formulation was determined using an antimicrobial activity test, and its effect on the product was investigated. The cytotoxic effect of the formulation obtained using the ARPE-19 cell line was investigated in the studies conducted. At the same time, the HET-CAM test was performed to investigate whether the formulation would cause any irritation to the fertilized egg cell membrane. Results: UV analysis revealed that brimonidine tartrate absorbed at 245 nm and crocetin absorbed at 420-440 nm. In antimicrobial activity testing, it was demonstrated that crocetin maintained antimicrobial activity up to a 50% concentration. The highest effect of the carrier formulation in the ARPE-19 cell line was observed at 96 hours. The formulation containing brimonidine tartrate was found to have mild irritant properties in the HET-CAM test, and no irritant properties were observed when applied with the carrier formulation and placebo. Conclusion: It has been proven that 150 µg/M crocetin in the formulation protects the product from microbes with its antimicrobial properties, and it has been observed with the ARPE-19 cell and HET-CAM tests that the formulation containing 5% methanol does not cause any toxic effects.