Everolimus quantification in peripheral blood mononuclear cells using ultra high performance liquid chromatography tandem mass spectrometry.

A reliable ultra high performance liquid chromatography tandem mass spectrometry method has been developed for the determination of everolimus in human peripheral blood mononuclear cells (PBMCs). Protein precipitation was used for sample preparation. Analysis was performed on an UPLC Waters Acquity system. Chromatography was carried out using a cartridge column MassTrak TDM C18 (2.1×10 mm) with 0.1% formic acid and 2 mM of ammonium acetate in water and 0.1% formic acid and 2mM of ammonium acetate in methanol mixture as a mobile phase delivered at a flow rate of 0.4 mL/min in gradient mode. The assay was linear over a range of 0-12.5 ng/mL. The analysis of quality control samples at 2.5, 5.0 and 10.0 ng/mL demonstrated good precision with relative standard deviation of less than 15%. Recoveries at concentrations of 2.5, 5.0 and 10.0 ng/mL were all greater than 83%. The method was successfully applied to the analysis of everolimus in PBMCs from blood samples of transplant recipients.

Impact of extracorporeal membrane oxygenation and continuous venovenous hemodiafiltration on the pharmacokinetics of oseltamivir carboxylate in critically ill patients with pandemic (H1N1) influenza.

PURPOSE: The neuraminidase inhibitor oseltamivir is a recommended treatment for influenza A (H1N1) infection. In rare cases, some patients develop influenza-associated multiple organ failures, requiring rescue therapies such as extracorporeal membrane oxygenation (ECMO) or continuous venovenous hemodiafiltration (CVVHDF). This study was designed to evaluate the impact of ECMO and CVVHDF on the pharmacokinetics of oseltamivir carboxylate (OC) in critically ill patients with pandemic (H1N1) influenza treated with oseltamivir. PATIENTS AND METHODS: Seven critically ill patients on venovenous ECMO for severe pandemic (H1N1) influenza associated with acute respiratory distress syndrome were treated with various doses of oseltamivir (75 or 150 mg twice daily). Because of acute kidney injury, 3 of them also received CVVHDF. OC, the active form of oseltamivir, was quantified in plasma, and main pharmacokinetic parameters were determined. RESULTS: OC Cmax (1029 ± 478 ng/mL) and area under the curve (9.00 ± 4.52 mcg·h/mL) for patients on ECMO with preserved renal function were comparable with those of healthy volunteers or noncritically ill patients. Patients both on ECMO and CVVHDF had 4-to 5-fold higher OC Cmax and area under the curve. CONCLUSIONS: ECMO by itself did not impact on the pharmacokinetics of OC. However, the drug accumulated in the plasma of patients on ECMO who also received CVVHDF for renal failure. Based on these results, we recommend that oseltamivir dosage should be decreased and plasma levels of OC be monitored in patients receiving CVVHDF because of acute kidney injury.