Follow the Area Under the Curve Not the Trough Concentration: A Case Study of Tacrolimus Monitoring in a Kidney Transplant Recipient Cotreated With Phenobarbital.

The authors described tacrolimus dosing in a kidney transplant patient concurrently treated with phenobarbital, where measuring the tacrolimus area under the curve was necessary to achieve adequate drug exposure and improve kidney function.

Volumetric absorptive microsampling for the quantification of tacrolimus in capillary blood by high performance liquid chromatography-tandem mass spectrometry.

Volumetric absorptive microsampling (VAMS) is an innovative alternative strategy to venipuncture for monitoring tacrolimus levels in transplant recipients. In this study, we aimed to validate a new high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for quantifying tacrolimus in blood collected by VAMS. Tacrolimus was extracted from dried blood tips in an original process involving sonication, protein precipitation and salting out.

A simple and fast liquid chromatography tandem mass spectrometry method to determine cyclosporine A concentrations in endomyocardial biopsies.

Measuring cyclosporine A (CsA), an immunosuppressive drug used to prevent heart transplant rejection, concentrations in myocardial biopsies might be more informative than its measurement in whole blood. Therefore, a fast, accurate and reproductive method to determine CsA concentration in this complex matrix is needed. We report the validation of a liquid chromatography tandem mass spectrometry method to measure CsA concentration in heart parenchyma, applicable to everyday practice.

Tacrolimus diffusion across the peripheral mononuclear blood cell membrane: impact of drug transporters.

Measuring tacrolimus (TAC) concentration in peripheral blood mononuclear cells (PBMCs) could better reflect the drug effect on its target (calcineurin (CaN) in lymphocytes) than whole blood concentrations. Mechanisms influencing TAC diffusion into PBMC are not well characterized. This work aimed at describing, ex vivo, TAC diffusion kinetics into PBMC and investigating the contribution of membrane transporters to regulate TAC intracellular concentration as well as the impact on CaN activity.