Simultaneous determination of four immunosuppressants by means of high speed and robust on-line solid phase extraction-high performance liquid chromatography-tandem mass spectrometry

In this study immunosuppressants, i.e. cyclosporin A (CyA), tacrolimus (TRL), sirolimus (SRL) and everolimus (RAD) were quantified in whole blood samples from immunosuppressant treated transplant recipients by an integrated on-line solid phase extraction-high performance liquid chromatography-tandem mass spectrometry (SPE-HPLC-MS/MS) system. This method has been developed to improve the following characteristics: speed, robust analysis, simultaneous determination and low cost. This can be achieved by the use of a perfusion column as an extraction cartridge in combination with a short HPLC column and highly selective and sensitive atmospheric pressure ionisation tandem mass spectrometry (API-MS/MS) in the multiple reaction monitoring (MRM) detection mode. This high throughput technique is perfectly appropriate for routine therapeutic drug monitoring (TDM) of organ transplanted patients. (C) 2004 Elsevier B.V. All rights reserved.