EP3983789A1 - METHOD FOR DETERMINING THE CONCENTRATION OF 4-[(4-METHYL-1- PIPERAZINYL)METHYL]-N-(4-METHYL-3-{[4-(3-PYRIDINYL)-2- PYRIMIDINYL] - AMINO} PHENYL)BENZ AMIDE (IMATINIB) IN PLASMA SAMPLES AND INSTRUMENT FOR THE REALISATION OF THE METHOD