Characterization of the Fluorescent Spectra and Intensity of Dabigatran and Dabigatran Etexilate: Application to HPLC Analysis with Fluorescent Detection†

There is considerable interest in dabigatran etexilate (Pradaxa) and its major metabolite, dabigatran, which has been shown to be an important inhibitor of Thrombin and clotting. In this study, the fluorescent excitation and emission spectra of dabigatran and dabigatran etexilate were characterized. In addition, a ultra performance liquid chromatography (UPLC) and high performance liquid chromatography (HPLC) method using fluorescent detection was developed for the analysis of dabigatran. Dabigatran and dabigatran etexilate were found to have excitation and emission maxima of 310 and 375 nm and 335 and 400 nm, respectively. UPLC analysis of dabigatran standards and plasma dabigatran samples were analyzed on a reversed phase C-18 column with methanol-water (70:30, v/v) as the mobile phase. The lower limit of quantitation for dabigatran was 10.0 ng/mL for both the standards and plasma samples. Standard curves were linear from 10.0 to 1000.0 ng/mL (R2 = 0.995). Within-day coefficient of variations of the fluorometric method at 50.0, 100.0 and 500.0 ng/mL were 1.38%, 4.83% and 2.31%, respectively. The intense fluorescent properties of dabigatran permit the sensitive and specific UPLC or HPLC fluorescent analysis of dabigatran.