Multi-center evaluation of a commercial Kit for tacrolimus determination by LC/MS/MS.

Objectives: A multi-center evaluation (3 sites) of the LC/MS/MS MassTrak tacrolimus Immunosuppressants Kit (Kit) was undertaken.

Design And Methods: Ten aspects of the analytical performance of the Kit were investigated based on FDA and CLSI guidelines.

Results: The linear analytical range of the procedure was between 0.

12-hour area under the curve cyclosporine concentrations determined by a validated liquid chromatography-mass spectrometry procedure compared with fluorescence polarization immunoassay reveals sirolimus effect on cyclosporine pharmacokinetics.

Liquid chromatographic (LC) procedures have been applied to cyclosporine therapeutic drug monitoring (TDM) since the agent was introduced in 1983. In recent years, the advance to mass spectrometric (MS) detection has enhanced the capability of LC by providing more sensitive and selective detection, a wider analytical range, faster turnaround time, and relative ease of use. Although fluorescence polarization immunoassay (FPIA) is a widely popular technology for cyclosporine TDM, it is compromised by a limited analytical range and lack of selectivity for parent drug.

Is microparticle enzyme-linked immunoassay (MEIA) reliable for use in tacrolimus TDM? Comparison of MEIA to liquid chromatography with mass spectrometric detection using longitudinal trough samples from transplant recipients.

In the larger transplant centers where technical expertise is available, liquid chromatography with mass spectrometric detection (LC-MS) for tacrolimus therapeutic drug monitoring is replacing the popular microparticle enzyme-linked immunoassay (MEIA) as a cost-effective alternative technology. As more labs convert to LC-MS, the accuracy, precision, selectivity, and sensitivity of the tacrolimus MEIA are being challenged, using data from large populations of clinical samples. However, little attention has been paid to how the results of particular procedures may differ within and among individual patients and to how such differences may relate to patients' characteristics or to relevant biochemical parameters.

Validation of a practical liquid chomatography with ultraviolet detection method for quantification of whole-blood everolimus in a clinical TDM laboratory.

Until now, only LC/MS methods for quantification of everolimus have been published. The authors validated an LC/UV method for quantification of everolimus from whole blood. The authors sought to improve on the protocol for sirolimus determination previously reported by French et al.

Analytic aspects of cyclosporine monitoring, on behalf of the IFCC/IATDMCT Joint Working Group.

The use of therapeutic drug monitoring strategies for cyclosporin (CsA) has evolved markedly in recent years since previous consensus guidelines were presented. Apart from the introduction of some new methods, the major change has been the shift away from the traditional predose/trough (C0) sample. The most popular alternative has been shown to be a 2-hour postdose (C2) sample.

International Federation of Clinical Chemistry/International Association of Therapeutic Drug Monitoring and Clinical Toxicology working group on immunosuppressive drug monitoring.

Issues surrounding the measurement and interpretation of immunosuppressive drug concentrations have been summarized in a number of consensus documents. The Scientific Division of the International Federation of Clinical Chemistry has formed a working group in collaboration with the International Association of Therapeutic Drug Monitoring and Clinical Toxicology. This paper sets out the goals of the working group in light of the developments that have occurred in the field of immunosuppressive drug monitoring since the publication of the last consensus documents.

Pharmacokinetic interactions augment toxicities of sirolimus/cyclosporine combinations.

This study correlated the dynamic effects of sirolimus (rapamycin; RAPA) and cyclosporine (CsA) alone versus in combination to produce renal dysfunction, myelosuppression, or hyperlipidemia, with their corresponding blood and tissue concentrations. After salt-depleted rats were treated with RAPA (0.4 to 6.