Metabolite profiling of dasatinib dosed to Wistar Han rats using automated dried blood spot collection

To characterize and enable efficient rat pharmacokinetic (PK) screening in early drug discovery, automated sampling of blood time points are routinely employed. With the development of dried blood spot (DBS) technology for drug level quantitation, an opportunity exists for the automated collection of rat PK time points using DBS. DBS, as an alternative sample collection technique has led to the increased collection of PK study samples for the quantitative analyses of drug candidates in both pre-clinical and clinical studies. However, the feasibility of using DBS samples for drug metabolite profiling including both phase I and phase II metabolites has not been well established. This work reports the study of metabolite profiling of dasatinib dosed to Wistar Han rats using automated DBS collection. Automated DBS and plasma collection using a rat AccuSampler (VeruTech AB, Sweden) was employed using dasatinib as a model compound. The DBS and plasma samples were extracted by methanol and acetonitrile and both plasma and DBS extracts were analyzed using a Sciex API4000 Qtrap mass spectrometer coupled to a Shimazdzu HPLC system. Dasatinib and its metabolites were analyzed by multiple reaction monitoring (MRM) and MRM trigger enhanced product ion scan (MRM-EPI). Both phase I oxidative metabolites and phase II glucuronide conjugates and sulfate conjugates were detected from both rat plasma and DBS samples. Overall, comparable metabolite profiles including phase I oxidative and phase II glucuronide and sulfate conjugates were observed from both extracts of plasma and DBS samples when using the untreated DBS cards for dasatinib. Chemically treated DBS cards such as DMPK-A and DMPK-B cards may affect the dasatinib metabolites. Similar PK parameters were obtained for dasatinib from both plasma and DBS samples, after correcting for blood to plasma ratio. The results obtained from this study suggest that collection of study samples by DBS can be used for metabolite profiling, however, the availability of limited samples may be a concern for multiple injections.