• 약학회지
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• 제31권2호
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• pp.112-115
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• 1987

Gypsogenin was derivatized with 2, 4-dinitrophenylhyclrazine prior to analysis with HPLC. Reversed-phase column (Du pont ODS) was used and the mobile phase was acetonitrile and water (60:40). The effluent was detected at 550nm using an U.V. detector and the retention time was approximately 9.2min. The concentration was quantitated by measuring the area and the detection limit was 0.2$\mu\textrm{g}$.

• Archives of Pharmacal Research
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• 제23권1호
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• pp.26-30
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• 2000

The enantiomers of the bronchodilator terbutaline were separated by reversed-phase high performance liquid chromatograhy after derivatization with 2,3,4,6-tetra-O-acetyl-\beta-D-glucopyranosyl isothiocyanate(GITC) reagent. The derivatization proceeded quantitatively within 1 h at room temperature. The corresponding diastereomeric thiourea derivatives were well resolved on an ODS column with acetonitrile-acetate buffer as a mobile phase. Elution orders of the diastereomers were confirmed by derivatization of R-(-)-terbutaline and S-(+)-terbutaline which were collected by semi-preparative chiral HPLC using Sumichiral OA-4700 column. The native fluorescence of terbutaline was quenched by derivatization with GITC. The detection limit was 25ng when monitored at UV 278 nm.

• Archives of Pharmacal Research
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• 제23권6호
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• pp.568-573
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• 2000

A reversed-phase high-performance liquid chromatographic method was developed to determine the optical purity of bevantolol enantiomers. (S)-(-)-Menthyl chloroformate((-)-MCF), (S)-(-)-$\alpha$-methylbenzyl isocyanate((-)-MBIC) and 2,3,4,6-tetra-O-acetyl-$\beta$-D-glucopyranosyl isothiocyanate(GITC), which can react with the secondary amine group of bevantolol were investigated as chiral derivatization reagents. Among them indirect chiral HPLC method using CITC gave the best result. The derivatization proceeded quantitatively within 20 min at room temperature. Separation of the enantiomers as diastereomers was achieved by reversed-phase HPLC within 20min using ODS column. Different ratios of (S)-(-)-bevantolol and (R)-(+)-bevantolol were prepared. Enantiomeric separation of these mixtures took place on a chiralcel OD column or, after derivatization with GITC, on a ODS column. No racemization was found during the experiment. This method allowed determination of 0.05% of either enantiomer in the presence of its stereoisomer and method validation showed adequete linearity over the required range.

• 분석과학
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• 제19권6호
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• pp.455-459
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• 2006

The extraction and separation of glabridin from licorice root by HPLC was performed in this work. First, by investigating the different extraction solvents, extraction methods and extraction times, a one-hour ultrasonic extraction procedure with ethyl acetate as the extraction solvent was optimized. Then the ethyl acetate extraction was applied to RP-HPLC for separation of glabridin. The column efficiencies and resolutions were experimentally investigated with different mobile phase compositions. Baseline separation of glabridin was obtained under the mobile phase composition of 50/50 vol.% (ACN/water). The retention time of glabridin was 20.3 min. The peak of glabridin was collected from the HPLC elution for several times and identified by LC/MS. Under the optimum extraction and HPLC separation methods, 1.26 g of glabridin per kg licorice root could be extracted.

• Bulletin of the Korean Chemical Society
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• 제24권12호
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• pp.1781-1784
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• 2003

Determination of Co(II) ion as a 4-(2-thiazolylazo)resorcinol(TAR) or 5-methyl-4-(2-thiazolylazo)resorcinol(5MTAR) chelate was accomplished by reversed-phase capillary high-performance liquid chromatography (RP-Capillary-HPLC) using a Vydac $C_4$ column and MeCN-water mixture as mobile phase. The effect of change in pH and MeCN percentage of the mobile phase on the retention factor, k and peak intensity were evaluated. It was found that 30% MeCN (v/v) of pH 5.60 or 7.20 was adequate as mobile phase when TAR or 5MTAR is used. Detection limit (D.L., S/N=3) in each case was $2.0\;{\times}\;10^{-7}$M (11.8 ppb) and $3.0\;{\times}\;10^{-7}$ M (17.7 ppb). The Co(II) ion in mineral and waste water was determined with the optimum column and mobile phase.

• Journal of Pharmaceutical Investigation
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• 제39권3호
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• pp.177-183
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• 2009

A rapid and sensitive reversed-phase high performance liquid chromatography (HPLC) method was developed for the determination of piroxicam in the rabbit plasma. After a treatment of plasma sample by liquid-liquid extraction, the drug was analyzed on an HPLC system with ultraviolet detection at 330 nm. HPLC was carried out using reversed-phase isocratic elution with a C18 column, a mobile phase of a mixture of acetonitril, doubly deionized water and acetic acid 43.74:56.00:0.26 v/v%) at a flow rate of 1.1 mL/min. The chromatograms showed good resolution and sensitivity and no interference of plasma. The calibration curve for the drug in plasma sample was linear over the concentration range of 0.01-2.0 ${\mu}$g/mL. The intra- and inter-day assay accuracies of this method ranged from 86.82% to 108.33% of normal values and the precision did not exceed 13% of relative standard deviation. The plasma concentration of piroxicam decreased to below the quantifiable limit at 12 hr after the i.v. bolus administration to rabbits following dose of 0.375 mg/kg yielding a apparen t plasma half life of 1.38 hr. The transdermal route prolongs plasma levels of piroxicam. The bioavailability, calculated from the dose-adjusted ratio of the $AUC_{transdermal}$ to the $AUC_{i.v.}$, was 7.44%. The plasma concentration of piroxicam was detected by 48 hr after the transdermal administration of patch at a dose of 32 mg/kg. This method was suitable for cutaneous absorption studies of piroxicam in the rabbit after transdermal administration of different types of dosages of the drug.

• Toxicological Research
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• 제14권4호
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• pp.563-567
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• 1998

This study was conducted to observe the distribution of josamycin, a macrolide antibiotic in flounder. Josamycin was administered orally to the flounder at the dose of 100 mg 1 kg josamycin in flounder. Josamycin in blood and various organs of flounder was analyzed using reversed phase HPLC. In blood kinetics study, Cmax was shown 9.50 $\mu\textrm{g}$/$m\ell$ at 45 min. after treatment and then decreased slowly up to 8th day. Concentration of josamycin in muscle was 0.47$\mu\textrm{g}$/g tissue at 11th day of the treatment and 0.41$\mu\textrm{g}$/g tissue at 7th day for liver. The concentration of josamycin in all the tested organs except gall bladder was decreased as the time passed. On the contrary, josamycin in gall bladder was increased 3.8 times at the day of 5th compared to that of the 1st day aftreatment.

• Archives of Pharmacal Research
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• 제29권11호
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• pp.1061-1065
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• 2006

A new chiral derivatization agent with sugar moiety, 2,3,4,6-tetra-O-acetyl-${\beta}$-D-galactopyranosyl isothiocyanate (GATC) was synthesized. Several ${\beta}-blockers$ were investigated for the possible separation of the enantiomers by reversed-phase HPLC after derivatization with this new chiral derivatization agent (GATC). GATC was reacted readily with ${\beta}-blockers$ at room temperature and the reaction mixture could directly be injected into the HPLC system. The corresponding diastereomers were well resolved on an ODS column with acetonitrile-ammonium acetate buffer as a mobile phase and monitored at UV 254 nm. The optimization of the derivatization procedure (concentration of GATC, reaction temperature and time) and HPLC conditions (pH and ionic strength of mobile phase) were investigated and compared with GITC.

• FOCUS: LIFE SCIENCE
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• 제1호
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• pp.3.1-3.7
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• 2024

The article discusses the critical role of chromatography in the analysis and purification of proteins in biopharmaceuticals, emphasizing the importance of comprehensive characterization for ensuring their safety and efficacy. It highlights the use of Avantor® ACE® HPLC columns for the separation and purification of proteins, focusing on the analysis of intact proteins using reversed-phase liquid chromatography (RPLC) with fully porous particles. This article also details the application of different mobile phase additives, such as TFA and formic acid, and emphasizes the advantages of using type B ultra-pure silica-based columns for efficiency and peak shape in biomolecule analysis. Additionally, it addresses the challenges of analyzing intact proteins due to slow molecular diffusion and introduces the concept of solid-core (or superficially porous) particles, emphasizing their benefits over traditional porous particles for the analysis of therapeutic proteins. Furthermore, it discusses the development of Avantor® ACE® UltraCore BIO columns, specifically designed for the high-efficiency separation of large biomolecules, such as proteins, and demonstrates their effectiveness in achieving high-resolution separations, even for higher molecular weight proteins like monoclonal antibodies (mAbs). In addition, it underscores the complexity of analyzing and characterizing intact protein biopharmaceuticals, requiring a range of analytical techniques and the use of wide-pore stationary phases, operated at elevated temperatures and with relatively shallow gradients. It highlights the comprehensive range of options offered by Avantor® ACE® wide pore columns, including both fully porous and solid-core particles, bonded with a variety of complementary stationary phase chemistries to optimize selectivity during method development. The use of ultrapure and highly inert base silica is emphasized for enabling the use of lower concentrations of mobile phase modifiers without compromising analyte peak shape, particularly beneficial for LC-MS applications. Then the article concludes by emphasizing the significance of reversed-phase liquid chromatography and its compatibility with mass spectrometry as a valuable tool for the separation and analysis of intact proteins and their closely related variants in biopharmaceuticals.

• Archives of Pharmacal Research
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• 제22권6호
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• pp.614-618
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• 1999

A reversed-phase high-performace liquid chromatographic method was developed to determine the optical purity of metoprolol enantiomers. The enantiomers were converted to diastereomeric derivatives using (-)-menthyl chloroformate reagent. Separation of the enantiomers as diastereomers was achieved by reversed-phase HPLC within 30 min using Inertsil C8 column. This method allowed determination of 0.05% of either enantiomer in the presence of its stereoisomer and method validation showed adequate linearity over the required range. Owing to the reaction condition during the derivatization with (-)-menthyl chloroformate, the possibility of racemization had to be established. Different ratios of (S)-(-)-metoprolol and (R)-(+)-metoprolol were prepared. Enantiomeric separation of these mixtures took place on a chiralcel OD column or, after derivatization with (-)-menthyl chloroformate, on a C8 column. The results form the these two independent separation systems were compared with trace racemization and were in very good agreement. No racemization was found during the experiment.