Green and sensitive detection of olopatadine in aqueous humor using a signal-on fluorimetric approach: GREEnness assessment.

Olopatadine (OLP) is widely utilized as an effective antihistaminic drug for alleviating ocular itching associated with allergic conjunctivitis. With its frequent usage in pharmacies, there arises a pressing need for a cost-effective, easily implementable, environmentally sustainable detection method with high sensitivity. This study presents a novel signal-on fluorimetric method for detecting OLP in both its pure form and aqueous humor. The proposed approach depends on enhancing the weak intrinsic fluorescence emission of OLP, achieving a remarkable increase of up to 680% compared to its intrinsic fluorescence. This enhancement is achieved by forming micelles around protonated OLP using an acetate buffer (pH 3.6) and incorporating a solution of sodium dodecyl sulfate (SDS) surfactant. A strong correlation (R = 0.9996) is observed between the concentration of OLP and fluorescence intensities ranging from 1.0 to 100.0 ng mL with a limit of detection of 0.22 ng mL. This described method is successfully employed for quantifying OLP in both its powder form and pharmaceutical eye drops. Furthermore, it demonstrates robust performance in determining OLP in artificial aqueous humor with a percentage recovery of 99.05 ± 1.51, with minimal interference from matrix interferents. Moreover, the greenness of the described method was evaluated.