UC Riverside

Our work focuses on routes toward fluorometric methodologies for detecting warfarin, an anticoagulant used in the management of a variety of thromboembolic disorders. Warfarin (a.k.a. Marevan, Coumadin, Waran, Jantoven) is one of the most widely prescribed medications for preventing thromboembolic events (blood clots). It is a drug with a narrow therapeutic index placing a strict requirement for careful monitoring of the patients taking it. In order to ensure that the effective physiological result is achieved and maintained, the dose must be adjusted accurately and frequently. Currently, estimation of the international normalized ratio (INR) of the prothrombin time (PT) is the most common method used for monitoring warfarin therapy. This estimation is actually a measure of the physiological result of a dose taken up to 72 hours prior. A rapid and clinically deployable method for measuring warfarin in blood plasma in real-time are needed in combination with PT/INR to further predict concentrations and prevent lapses in patient compliance, such as changes in diet and interactions with other medications that can result in falling out of the warfarin therapeutic range. Due to their inherently high sensitivity, fluorescence techniques are a preferred approach for the development of biosensing applications. Warfarin, a derivative of coumarin, absorbs and fluoresces in the UV region of the spectrum. Hence, it is immensely challenging and impractical to use warfarin fluorescence for its detection in biological fluids due to the presence of other UV-absorbing chromophores and fluorophores. The utilization of warfarin’s inherent properties and structural dependence on media pH, provides a direct handle for warfarin sensing. Herein, we characterized the photophysical properties of warfarin in solvents with varying temperature, polarity and viscosity, while also demonstrating rapid extraction and quantification of warfarin from aqueous and blood plasma samples using fluorescence spectroscopy.