Quantification Analysis of Three Immunosuppressants in Whole Blood Based on Self-developed Liquid Chromatography-Mass Spectrometer

A method for simultaneous quantification of tacrolimus (TAC), sirolimus (SIR), and cyclosporine A (CSA) in whole blood was developed. Whole blood samples were processed using protein precipitation and quantitatively analyzed using a self-developed QLIT-6610MD liquid chromatography-tandem mass spectrometry system. The method demonstrated good specificity, with linear ranges of 0.50‒50.00 ng/mL for TAC, 1.00‒50.00 ng/mL for SIR, and 5.00‒1000.00 ng/mL for CSA. The correlation coefficients (R2) were all greater than 0.99. The limits of detection were 0.15, 0.40 and 1.50 ng/mL, and the limits of quantitation were 0.50, 1.00, and 5.00 ng/mL, respectively. The accuracy range for the three drugs was 88.02%‒98.10%, with intra-day and inter-day precision ranges of 4.66%‒12.29% and 5.85%‒12.47%, respectively. The coefficient of variation for matrix factor was better than 11.27%, and the sample stability was good. Bland-Altman analysis was performed on 60 clinical samples using both QLIT-6610MD and AB QTRAP 6500+, showing high consistency between their quantitative results. The developed method could rapidly and accurately quantify these three immunosuppressants in human whole blood, which could meet clinical testing requirements.