2.3 Bioanalytical Method
Human whole blood was collected and centrifuged to obtain plasma. The harvested plasma was transferred to precharged citric acid tubes to obtain acidified plasma (40 mM) for measurement of iberdomide and M12, with two validated human plasma liquid chromatography-tandem mass spectrometry assays (LC-MS/MS): 1) solid phase extraction (SPE, Waters Oasis Elution HLB cartridges) for iberdomide or M12 sample cleanup; 2) chiral LC (Chiral Tech, CHIRALPAK™ CBH, 100 × 3 mm, 5 μm column) for iberdomide separation (from its R-enantiomer), or achiral LC (Phenomenex Synergi Polar-RP, 2.0 x 50 mm, 4 μm column) for M12 separation; and 3) Turbo IonSpray® with MS/MS detection for iberdomide (SCIEX API 4000, Framingham, MA) or M12 (SCIEX API 5500). The calibration curves for iberdomide and M12 ranged from 0.1 to 100 ng/mL and 0.1 to 50 ng/mL in acidified human plasma respectively, with the lower limit of quantification (LLOQ) being 0.1 ng/mL for both assays. In both method validation and study sample analysis, the precision and accuracy data for standard/quality control samples were well within acceptance criteria for both iberdomide and M12.