Quantification of cyclosporine A in peripheral blood mononuclear cells by liquid chromatography-electrospray mass spectrometry using a column-switching approach

Quantitative bioanalysis of peptides by liquid chromatography coupled to (tandem) mass spectrometry

“…On-line SPE allows direct injection of the biological sample as it couples an extraction column with the analytical column, usually by column-switching. This technique has frequently been described for quantitative assays of the immunosuppressant cyclosporin A [116][117][118][119]122,126,142], as well as for several other peptides [56,62,67,106,[143][144][145][146]. Turbulent flow chromatography (TFC) is an on-line SPE technique using extraction columns with large particle sizes, allowing high flow rates.…”

“…6). Structurally different ISs have been used, because of the restricted availability of the structural analogs or because one IS is preferred for the simultaneous quantification of several analytes [121][122][123]125,142]. However, the use of an IS for cyclosporin A quantification has also been reported to be unnecessary [116][117][118]120], particularly when no off-line SPE step is performed.…”

Determination of eptifibatide concentration in human plasma utilizing the liquid chromatography–tandem mass spectrometry method

“…When quantifying peptides or proteins, SRM [6,7] or SIM [8] has often been employed with satisfactory sensitivity. However, in some cases, due to the structures or physicochemical properties of the analytes, common SRM and SIM procedures are not enough to meet the requirements.…”

“…Indeed, this method has been previously used to measure the concentration of cyclic peptides such as colistin (a cyclic heptapeptide and tripeptide side chain acylated at the N-terminus) [6] and melanotan-II (a cyclic heptapeptide, M W : 1024 Da) [7]. Furthermore, in some cases, LC-MS methods using the SIM (selected ion monitoring) process have also been applied to measure the concentration of cyclic peptides such as cyclosporine A (a cyclic undecpeptide, M W : 1202 Da) [8]. To date, however, there is no quantification method reported for eptifibatide.…”

Analysis of cyclosporine A and its metabolites in rat urine and feces by liquid chromatography–tandem mass spectrometry

“…Therefore, the method of high performance liquid chromatography with UV detection (HPLC-UV) appears to be more appropriate for such analyses than immunoassays [5][6][7]. Recently, analytical methods for CyA detection by liquid chromatography-mass spectrometry (LC-MS) or LC-MS/MS were developed [8][9][10][11]. Compared with HPLC-UV, LC-MS/MS assays were found to be over ninefold times more sensitive than HPLC-UV [12,13].…”