Cyclosporine A (CyA) is an immunosuppressant cyclic undecapeptide used for the prevention of organ transplant rejection and in the treatment of several autoimmune disorders. An ultra high performance liquid chromatography-tandem mass spectrometry method (UHPLC-MS/MS) to quantify CyA in lipid nanosystems and mouse biological matrices (whole blood, kidneys, lungs, spleen, liver, heart, brain, stomach and intestine) was developed and fully validated. Chromatographic separation was performed on an Acquity UPLC(®) BEH C18 column with a gradient elution consisting of methanol and 2mM ammonium acetate aqueous solution containing 0.1% formic acid at a flow rate of 0.6mL/min. Amiodarone was used as internal standard (IS). Retention times of IS and CyA were 0.69min and 1.09min, respectively. Mass spectrometer operated in electrospray ionization positive mode (ESI+) and multiple reaction monitoring (MRM) transitions were detected, m/z 1220.69→1203.7 for CyA and m/z 646→58 for IS. The extraction method from biological samples consisted of a simple protein precipitation with 10% trichloroacetic acid aqueous solution and acetonitrile and 5μL of supernatant were directly injected into the UHPLC-MS/MS system. Linearity was observed between 0.001μg/mL-2.5μg/mL (r≥0.99) in all matrices. The precision expressed in coefficient of variation (CV) was below 11.44% and accuracy in bias ranged from -12.78% to 7.99% including methanol and biological matrices. Recovery in all cases was above 70.54% and some matrix effect was observed. CyA was found to be stable in post-extraction whole blood and liver homogenate samples exposed for 6h at room temperature and 72h at 4°C. The present method was successfully applied for quality control of lipid nanocarriers as well as in vivo studies in BALB/c mice.
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