Determination of meropenem in capillary plasma microsamples using LC–MS/MS

Background: The measurement of meropenem plasma concentrations is employed for dosing regimen individualization. The aim of this study was to develop and validate a LC–MS/MS assay for quantification of meropenem in capillary plasma microsamples. Methods: Samples were prepared by protein precipitation with acetonitrile, followed by clean-up with dichloromethane. The method was validated and applied to 12 paired samples of venous and capillary plasma. Results: The method was linear in the range of 0.5–50 μg/ml. Matrix effects were minimal. Inter- and intra-assay were 3.8–7.9% and 2.7–5.5%, respectively, while accuracy was 91.7–100.6%. Concentrations in capillary and venous plasma were highly correlated. Conclusion: An assay for the quantification of meropenem in capillary plasma microsamples was fully validated, showing potential for clinical application.