Quantification of dabigatran and indirect quantification of dabigatran acylglucuronides in human plasma by LC-MS/MS

Background: An assay for the quantification of dabigatran and its active metabolites, dabigatran acylglucuronides, has not previously been described in detail. Results: For the quantification of total dabigatran concentration (free dabigatran and acylglucuronides), samples were subjected to alkaline hydrolysis. For the quantification of free dabigatran, samples were acidified with ammonium formate. Following acetonitrile protein precipitation, the samples were analyzed by LC-MS/MS using gradient elution to ensure separation of dabigatran from dabigatran acylglucuronides. Mean recoveries 98% were achieved. The assay was validated over the range 2.5-1000 ng/ml dabigatran, imprecision was <9% CV (<15% at LLOQ) and accuracy was 101-114%. Conclusion: An assay for dabigatran with indirect quantification of dabigatran acylglucuronides in plasma was developed, validated and applied.