Page 24 - Shimadzu Journal vol.2 Issue1
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Topics                                                                                                                                                                                                                                 Topics




                                                                                                                                      In addition to five reversed phase separation modes, including   3. Mechanism behind Co-Sense for BA                                                  Fig. 5 shows the recovery rates and peak shapes when a dilution
                High-Throughput Bioanalysis with On-Line Sample                                                                       ODS, the Shim-pack MAYI series provides a strong cation   Fig. 3 shows the flow schematic for Co-Sense for BA. The standard                           trap is used with indomethacin samples likewise spiked with
                Pretreatment Using Restricted Access Media                                                                            exchange mode and a strong anion exchange mode (Table 1).  configuration adopts a sample injection method based on the                                plasma, and large-volume 100 µL, 200 µL, and 500 µL samples are
                The Shimadzu Co-Sense for BA System Solution                                                                                                                             dilution trap method, to ensure reliable trapping and                                              injected. Even with the 500 µL injection, a recovery rate of almost
                                                                                                                                       Table 1 Stationary Phases and Separation Modes in the   concentration of intended components.                                                        100 % is achieved, and the peak shape is maintained.
                                                                                                                                             Shim-pack MAYI Series
                                                                                                                                                                                         While the sample injected from the autosampler is introduced to
            1. Introduction                                                                                                             Product Name    Stationary Phase  Separation Mode  the trap column via the mobile phase from the pump unit for
            Because of its high sensitivity and selectivity, analysis via LC/MSMS                                                       Shim-pack MAYI-ODS(G)   Octadecyl  Reversed Phase  sample injection (a), it is diluted automatically by the dilution
            is now widely used in the context of pharmacokinetic research,                                                              Shim-pack MAYI-C14(G)  Tetradecyl  Reversed Phase  solvent delivered from the pump unit for on-line dilution (b), and
            drug metabolism research, bioequivalence tests, and other                                                                   Shim-pack MAYI-C8(G)  Octyl  Reversed Phase      introduced to the trap column, the Shim-pack MAYI column (c).
            measurements of drug concentrations in biological samples                                                                   Shim-pack MAYI-C4(G)  Butyl  Reversed Phase      Thanks to this dilution process, interactions with the matrix and
            (bioanalysis). However, in more than a few situations, there are                                                            Shim-pack MAYI-C1(G)  Methyl  Reversed Phase     the impact of the sample solvent are suppressed, while the
            problems with impurities such as proteins originating from                                                                  Shim-pack MAYI-SCX(G)  Sulfonate  Strong Cation Exchange Mode  intended components are introduced to the trap column, thus
            organisms; ionization suppression caused by matrix effects;                                                                 Shim-pack MAYI-SAX(G)  Trimethylammonium  Strong Anion Exchange Mode  providing reliable trapping and concentration. A liquid containing
            ionization enhancement; degradation of precision, accuracy, and                                                                                                              a buffer solution and a low-concentration organic solvent is used
            reproducibility; and carryover. Accordingly, sample pretreatment   Note: "Co-Sense for BA", the name of this product, is an   The stationary phase is selected in accordance with the polarity of   as the dilution solvent.
            methods have become a very important topic of investigation.   abbreviation of "the Collaboration of Shimadzu and Eisai for New   the target compound. However, the type of extraction solvent   Intended components concentrated in the trap column are
            Conventionally, the following have been utilized as serum and   Systematic Efficiency." "Co-Sense" refers to "collaboration of   from the column and the trap dilution solvent must also be   introduced to the analysis line via valve switching. The mobile
            plasma pretreatment methods, primarily with the objective of   sensibilities" the concept behind this product. This refers to the   investigated [5], [6], [13]. In investigations utilizing the strong   phase from the pump unit for analysis (d) then delivers them to
            deproteinization.                                  integration of user and manufacturer to create new value. In           cation exchange mode (SCX), a variety of evaluations have been   the analysis column (e) where they are separated and analyzed. In
                                                               addition, the MAYI pretreatment column is named using the initials     performed. These include the recovery rate of differing pKa   addition to UV and PDA detectors, MS detectors can also be
             1) Addition of acids or organic solvents to denature proteins and   of the four researchers at Eisai responsible for developing it.  compounds in plasma, evaluation of the decrease in matrix effects   connected.
               render them insoluble, for removal by centrifuging                                                                     in MS detection, and evaluation of metabolites in rat bile through
                                                                                                                                      combination with a C4 column [7], [8], [9]. In investigations    E
             2) Physical removal using ultrafiltration membranes  2. Methylcellulose-Immobilized Pretreatment Column,                 utilizing the strong anion exchange mode (SAX), results have been
             3) Off-line pretreatment using solid phase extraction cartridges  ɹ Essential to Co-Sense for BA                         evaluated related to the analysis of aspirin and its metabolites         F
                                                                                                                                      (such as acetylsalicylic acid) in rat plasma [10].
             4) On-line pretreatment using solid phase extraction columns  Operating Principles Behind the Shim-pack MAYI Series of
                                                               Biological Sample Pretreatment Columns                                 With an optimized particle size and a special coating technique,
                                                                                                                                      the Shim-pack MAYI column provides a high protein removal
            In method (1), it is important to evaluate whether the drugs are   The outer surface of the silica gel (50 um) is coated with a   efficiency and long-term stability. In addition, by increasing sample
            denatured, while in method (2), adsorption by raw materials must   water-soluble polymer (Methylcellulose). Only the pore interior is   permeability, the occurrence of pressure increases (clogging) due    D
            be evaluated. When considering treatment time, cost, and data   chemically modified by octadecyl or other functional groups [5].   to adsorption of sample components has been suppressed, and
            reproducibility, method (4), which can be implemented on-line,   Macromolecules such as proteins are blocked by the water-soluble   excellent reproducibility is shown, even in consecutive
            seems the most likely to increase overall productivity.  polymer layer on the outer surface and do not enter the pores. As   multi-sample analysis. Fig. 2 shows the changes to the
                                                               a result, they are not retained by the stationary phase, and are
            In terms of pretreatment columns in method (4), in addition to                                                            chromatogram when an isopropylantipyrine sample spiked with
            reversed phase mode, normal phase mode, and ion exchange   quickly eluted. In contrast, drugs and other typical organic low   plasma is injected 300 times. Essentially the same chromatogram    B        C
            mode, columns classified by restricted access media (RAM) are   molecular compounds penetrate into the pores, and are retained   is obtained, even after 300 injections. This series consists of
            now utilized. Product types have also increased, and have been   by the stationary phase on the inner surface. They are then eluted   cartridge type columns, which are attached to a special column
            subject to review [1], [2]. RAM is a highly functional packing   under appropriate conditions and analyzed with the analysis   holder.                                        Fig. 3  Flow Schematic for the Standard Configuration of
            material, designed so that the outer surface of the packing   column. Fig. 1 shows the behavior of drugs (low-molecular   In addition to these, Eisai has also evaluated weak cation   Co-Sense for BA
            particles removes proteins and other biological macromolecules,   compounds) and proteins at the surface of the packing material in   exchange mode columns [11].
            restricting their internal penetration. Conversely, the internal pores   the Shim-pack MAYI-ODS.                                                                             4. Effective Trapping and Concentration Using a Dilution Solvent
            or inner surface captures the target low molecular compounds.
                                                                                                                                                                                         With Co-Sense for BA, the injected sample is diluted at a constant
            In conjunction with Eisai Co., Ltd., Shimadzu has developed and                                                                                                              rate. This is performed to suppress interactions between intended
            commercialized unique restricted access type trap columns                                                                                                                    components and proteins in the sample, and to release intended
            (Shim-pack MAYI series) classified as RAM, and an LC system with                                                                                                             components bound to proteins. In this way, even components
            on-line pretreatment functionality via valve switching (Co-Sense                                                                                                             with a high binding rate are reliably trapped and concentrated. A
            for BA). The Co-Sense for BA allows large volumes of plasma,                                                                                                                 liquid containing a buffer solution and a low-concentration
            serum and other biological samples to be injected and analyzed.                                                                                                              organic solvent is used as the dilution solvent. As a result, even
            High-concentration proteins and electrolytes, which are                                                                                                                      plasma and serum samples can be injected directly. In addition,
            unnecessary components, are almost completely removed. Since                                                                                                                 high sensitivity is achieved due to excellent recovery rates and
            pretreatment involves direct injection, there is no loss of valuable                                                                                                         peak shapes, even for large-volume injections [6], [7], [9], [10],
            samples, and stable data can be obtained even with unstable                                                                                                                  [12], [13].
            components. Further, the adoption of dilution trap method                                                                                                                    Fig. 4 shows a comparison of recovery rates based on the presence
            maintains peak shape and enhances sensitivity by concentrating                                                                                                               or absence of on-line dilution, utilizing indomethacin samples
            the intended components, thereby providing stable recovery rates                                                                                                             spiked with plasma. With dilution, the recovery rate is almost 100
            and reproducibility [3], [4], [5], [6], [7]. These features effectively                                                    Fig. 2  Evaluation of the Durability of the Shim-pack MAYI-ODS  %. Without dilution, the recovery rate falls to approximately 50 %.
            result in the protection of analysis columns and the LC/MS
            interface, as well as the reduction of matrix effects, enabling the
            acquisition of efficient, highly reliable results [8].
                                                               Fig. 1  Behavior of Drugs (Low-Molecular Compounds) and
                                                                    Proteins at the Surface of the Shim-pack MAYI-ODS

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