Anion species-triggered antibody separation system utilizing a thermo-responsive polymer column under optimized constant temperature

Inoue

et al. 2022

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Therapeutic drug monitoring (TDM) is an effective pharmacological approach for controlling drug concentration in a patient’s serum. Herein, a new two-dimensional chromatography system was developed using two poly(N-isopropylacrylamide) (PNIPAAm)-modified bead-packed columns for effective and safe drug monitoring. PNIPAAm-modified silica beads were prepared as packing materials using atom transfer radical polymerization of NIPAAm. The increase in the retention times of the drugs requiring TDM with increasing temperature, was attributed to enhanced hydrophobic interactions at elevated temperatures. The drugs and serum proteins were separated on the prepared column at 40 °C using an all-aqueous mobile phase. Differences in the hydrophobic interactions accounted for the elution of the serum proteins and drugs at short and long retention times, respectively, and a primary column was employed to separate the serum proteins and drugs. After eluting the serum proteins from the column, the drug was introduced into the secondary column, leading to a peak of its purified form and enabling determination of the drug concentration. Two-dimensional temperature-responsive chromatography can benefit TDM by allowing the drug concentration in the serum to be measured in all-aqueous mobile phases without sample preparation.

Section: Resultscontrasting

confidence: 68%

Two-dimensional temperature-responsive chromatography using a poly(N-isopropylacrylamide) brush-modified stationary phase for effective therapeutic drug monitoring

Inoue

et al. 2022

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“…Ordinarily, drug concentration must be determined in serum, and deproteination of the serum sample (by the addition of organic solvent) is required before HPLC column injection to avoid serum protein adsorption onto the beads in the column resulting in the column clogging. Thermoresponsive ionic copolymers composed of NIPAAm and ionic monomers have been shown to adsorb proteins via multiple hydrophobic and electrostatic interactions 51 – 58 . In contrast, the PNIPAAm homopolymer modified-bead packed column scarcely adsorbs proteins even at high column temperatures 51 , 52 .…”

Section: Resultsmentioning

confidence: 99%

Temperature responsive chromatography for therapeutic drug monitoring with an aqueous mobile phase

Nishiyama

Inoue

et al. 2021

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Therapeutic drug monitoring is a key technology for effective pharmacological treatment. In the present study, a temperature-responsive chromatography column was developed for safe and simple therapeutic drug monitoring without the use of organic solvents. Poly(N-isopropylacrylamide) (PNIPAAm) hydrogel-modified silica beads were prepared via a condensation reaction and radical polymerization. The temperature-dependent elution behavior of the drugs was observed using a PNIPAAm-modified silica-bead packed column and an all-aqueous mobile phase. Sharp peaks with reproducible retention times were observed at temperatures of 30 °C or 40 °C because the PNIPAAm hydrogel on the silica beads shrinks at these temperatures, limiting drug diffusion into the PNIPAAm hydrogel layer. The elution behavior of the sample from the prepared column was examined using a mixture of serum and model drugs. The serum and drugs were separated on the column at 30 °C or 40 °C, and the concentration of the eluted drug was obtained using the calibration curve. The results show that the prepared chromatography column would be useful for therapeutic drug monitoring because the drug concentration in serum can be measured without using organic solvents in the mobile phase and without any need for sample preparation.

“…Polymer-modified silica beads, which were used as packing materials, were prepared by initiator modification via condensation, followed by radical polymerization of the functional monomers for polymer modification (Fig. 1 A) 61 – 63 . First, N -ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (6.18 g, 25.0 mmol) and V-501 (3.50 g, 12.5 mmol) were dissolved in 25 mL of N,N -dimethylformamide (DMF) in a 100 mL flask.…”

Section: Methodsmentioning

confidence: 99%

Chromatography columns packed with thermoresponsive-cationic-polymer-modified beads for therapeutic drug monitoring

Takagi

Nakada

et al. 2022

Self Cite

Therapeutic drug monitoring, which is used to determine appropriate drug doses, is critical in pharmacological therapy. In this study, we developed thermoresponsive chromatography columns with various cationic properties for effective therapeutic drug monitoring. Thermoresponsive cationic copolymer poly(N-isopropylacrylamide-co–n-butyl methacrylate-co–N,N-dimethylaminopropyl acrylamide) (P(NIPAAm-co-BMA-co-DMAPAAm))-modified silica beads, which were used as the chromatographic stationary phase, were prepared by modifying the radical initiator of the silica beads, followed by radical polymerization. Characterization of the prepared silica beads demonstrated that thermoresponsive polymers with various cationic properties successfully modified the beads. The elution behavior of several steroids in the prepared bead-packed columns at various temperatures indicated that the optimal column operating temperature was 30 °C. Appropriate measurement conditions for 13 drugs were investigated by varying the cationic properties of the columns and the pH of the mobile phase. Drug concentrations in serum samples were determined using the developed columns and mobile phases with a suitable pH. Voriconazole concentrations in human serum samples were determined using the developed columns with all-aqueous mobile phases. We anticipate that the developed chromatography columns can be used for therapeutic drug monitoring because drug concentrations can be measured using all-aqueous mobile phases that are suitable in clinical settings.