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Characterization                Quality Control               Pharmacokinetics


                     Evaluating the Concentration of Antibody Drugs in Blood                                                            Nexera Mikros





                                High-Sensitivity LC/MS Bioanalysis of                                                                                      benefits

                                           Trastuzumab by nSMOL                                                                                                                                                                              Cell Line Optimization
                                                                                                 click here                                     •   Micro-flowrate LC-MS system that offers both high sensitivity and high throughput.
                                                                                                                                                •   Easy one-step attachment of analytical columns and connection to the LC-MS
                     Operating Principle and Features                     Table 3   MRM Transitions of Quantified Peptides in Trastuzumab
                                                                   Peptide  MRM transition    Purpose                                             ionization interface.
                     High-performance liquid chromatograph mass spectrometer (LC-MS)    P 14 R  512.1 > 292.3 (b3+)  For quantitation (IS)
                     systems enable higher performance analysis by decreasing the flowrate   512.1 > 389.3 (b4+)  For structural confirmation
                     in the LC unit and improving the ionization and ion uptake efficiency   512.1 > 660.4 (b6+)  For structural confirmation  Direct injection system:   Small injection volumes make it especially well-suited for analyzing desalted or otherwise   Culture
                     in the MS unit. The Shimadzu Nexera Mikros is a micro LC-MS system    IYPTNGYTR  542.8 > 404.7 (y7++)  For quantitation                      pretreated samples.

                                                                                              For structural confirmation
                                                                           542.8 > 808.4 (y7+)
                     that reduces the LC flowrate to a micro level (approx. 1 to 10 μL/  542.8 > 610.3 (y5+)  For structural confirmation
                     min). That results in between several times to several tens of times   Note:  The peptide (signature peptide) was selected from trypsin peptide fragments that include
                     higher sensitivity than the previous semi-micro LC-MS system, while   complementarity-determining regions (CDRs) that determine antibody specificity.
                     maintaining the same robustness and throughput.
                                                                   Results
                     Measurement Method and Conditions
                                                                   Measured concentrations of trastuzumab in blood plasma correlated
                     The ELISA ligand-binding assay method was the primary method   closely with concentration settings, with an R  value of 0.99 or higher
                                                                                              2
                     used to determine the concentration of antibody drugs in the blood.   and excellent accuracy and precision. Furthermore, the Nexera Mikros                                                                              Purification
                     This example describes a quantitative method that is based on using   system was also used to confirm that the LLOQ value for trastuzumab
                     a high-sensitivity LC-MS system. Human blood plasma spiked with   in blood plasma is 0.00763 μg/mL.                Trap and elute system:   System for increasing sensitivity of semi-micro systems without changing the injection volume or
                     a trastuzumab standard and blank blood plasma were analyzed as   A comparison of MRM chromatograms from the Nexera Mikros system            other parameters
                     samples. For all the antibody drugs, Fab-derived peptides were obtained   (Fig. 1) and a typical semi-micro LC-MS system (Fig. 2) shows that the
                     using the nSMOL method, which allowed using the same protocol   Nexera Mikros is able to detect with ample sensitivity concentrations
                     for all samples. These were analyzed to quantify the concentration of   that the semi-micro LC-MS system was not able to detect.
                     trastuzumab in the blood plasma based on the analytical conditions
                     indicated in Tables 1 to 3.
                                   Table 1   LC Analytical Conditions
                     [Analytical]:                                                                                                                                                                                                           Characterization
                      Column:         Shim-Pack MC C18
                                      (50 mm × 0.175 mm I. D., X µm)
                      Mobile phase A:  0.1 % Formic acid in water
                      Mobile phase B:  0.1 % Formic acid in Acetonitrile
                      Gradient:       5 % (0 – 0.5 min) →
                      (B. Conc. )     → 25 % (0.5 – 4.5 min) →
                                      → 95 % (4.51 – 5.0 min) →                                                                         Ionization promotion system:   System for increasing negative mode sensitivity by adding an LC-20AD nano unit to each
                                      → 5 % (5.01 – 11.0 min)                                                                                                           of the two systems above
                      Flowrate:       4.0 µL/min
                      Column Temp.:   50 °C
                     [Trap]
                      Trap column:    L-column 2 ODS Micro                                                                                                                                                                                   Quality Control
                                      (5 mm × 0.3 mm I.D., X µm)
                      Mobile phase A:  0.05 % Trifluoroacetic acid in water
                      Mobile phase B:  0.1 % Formic acid in Acetonitrile
                      Column Temp.:   50 °C
                      Injection Volume:   10 µL
                                   Table 2   MS Analytical Conditions         Fig. 1   MRM Chromatograms (Nexera Mikros)
                      Ionization:     ESI Positive
                      DL Temp.:       250 °C
                      Heat Block Temp.:  400 °C
                      ESI Temp.:      100 °C                                                                                                                                                                                                 Pharmacokinetics
                      Nebulizer Gas:  2 L/min
                      Drying Gas:     OFF
                      Heating Gas:    3 L/min
                                                                                                                                        Specifications
                     Conclusion                                                                                                          Solvent delivery unit  LC-Mikros                 Flowrate range:  1 to 500 μL/min

                     Using the nSMOL method in combination with the Nexera Mikros                                                        System pressure capacity  80 MPa
                     system enables high-sensitivity quantitation of antibody drugs in blood   Fig. 2   MRM Chromatograms (Semi-Micro LC-MS)  Autosampler     SIL-40C XR                  Injection volume range:  0.1 to 50 µL              Others
                     without sacrificing throughput.
                                                                   Application Examples                                                  Ionization unit      Micro-ESI 8060 or Micro-ESI 9030
                                                                                                                                         Column oven          CTO-Mikros
                                                                   • Analyzing lipid mediators with high sensitivity
                                                                                                                                                              (UF-Link enables connecting/disconnecting columns easily with zero dead volume.)


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