• Journal of Pharmaceutical Investigation
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• v.39 no.1
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• pp.65-71
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• 2009

The aim of the present study was to evaluate the bioequivalence of two domperidone maleate tablets, Motilium-$M^{(R)}$ Tablet (Janssen Korea Ltd., reference product) and $Toriem^{(R)}$ Tablet (Daewon Pharm. Co., Ltd., test product). Domperidone was extracted by liquid-liquid extraction using tert-butyl methyl ether and separated in less than 3 min on $C_{18}$ reverse-phase column using an isocratic elution. A tandem mass spectrometer, as detector, was used for quantitative analysis in positive mode by a multiple reaction monitoring mode to monitor the m/z $426.1{\rightarrow}119.1$ and the m/z $837.4{\rightarrow}158.2$ transitions for domperidone and the internal standard (roxithromycin), respectively. Calibration curves, from $0.05{\sim}50$ ng/mL of domperidone, showed correlation coefficients (r) higher than 0.9941. Intra day and inter day precision (C.V. %) for quality control were ranged from 10.04 to 16.09% and from 10.87 to 18.69%, respectively. The lower limit of quantification (LLOQ) of domperidone was 0.05 ng/mL. The method described is precise and sensitive and has been successfully applied to the study of bioequivalence of domperidone in 24 healthy Korean volunteers. Twenty-four healthy male Korean volunteers received a single dose of each medicine ($2{\times}12.72\;mg$ domperidone maleate) in a $2{\times}2$ crossover study. There was a one-week washout period between the doses. Plasma concentrations of domperidone were monitored for over a period of 24 hr after the administration. $AUC_{0-t}$ (the area under the plasma concentration-time curve) was calculated by the linear trapezoidal rule. $C_{max}$ (maximum plasma drug concentration) and $T_{max}$ (time to reach $C_{max}$) were compiled from the plasma concentration-time data. The 90% confidence intervals for the log transformed data were within acceptable range of log 0.8 to log 1.25 (e.g., $log\;0.92{\sim}log\;1.05$ for $AUC_{0-t}$, $log\;0.81{\sim}log\;1.05$ for $C_{max}$). The major parameters, $AUC_{0-t}$ and $C_{max}$ met the criteria of KFDA for bioequivalence indicating that $Toriem^{(R)}$ tablet is bioequivalent to Motilium-$M^{(R)}$ tablet.

• Bulletin of the Korean Chemical Society
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• v.28 no.5
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• pp.737-744
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• 2007

An isotope dilution-liquid chromatography/tandem mass spectrometric method was developed as a candidate reference method for the accurate determination of acrylamide in potato chips, starch-rich foodstuff cooked at high temperature. Sample was spiked with 13C3-acrylamide and then extracted with water. The extract was further cleaned up with an Oasis HLB solid-phase extraction (SPE) cartridge and an Oasis mixed-phase cation exchange (MCX) SPE cartridge. The extract was analyzed by using LC/ESI/Tandem MS in positive ion mode. LC with a medium reversed-phase (C4) column was optimized to obtain adequate chromatographic retention and separation of acrylamide. MS was operated to selectively monitor [M+H]+ ions of the analyte and its isotope analogue at m/z 72 and m/z 75, respectively. Sample was also analyzed by the LC/MS with selectively monitoring the collisionally induced dissociation channels of m/z 72 → m/z 55 and m/z 75 → 58. Compared to the LC/MS chromatograms, the LC/MS/MS chromatograms showed substantially reduced background chemical noises coming from solvent clusters formed during ESI spray processes and interferences from sample matrix. Repeatability and reproducibility studies showed that the LC/MS/MS method is a reliable and reproducible method which can provide a typical method precision of 1.0% while the LC/MS results are influenced by chemical interferences.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.243-244
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• 2013

Over the past 15 years, several groups have incorporated radio-frequency quadrupole (RFQ) based instruments before the accelerator in accelerator mass spectrometry (AMS) systems for ion-gas interactions at low kinetic energy (＜40 eV). Most AMS systems arebased on a tandem accelerator, which requires negative ions at injection. Typically, AMS sensitivity abundance ratios for radioactive-to-stable isotope are limited to Xr/Xs ＞10^-15, and the range of isotopes that can be analyzed is limited because of theneed to produce rather large negative ion beams and the presence of atomic isobaric interferences after stripping. The potential of using low-kinetic energy ion-gas interactions for isobar suppression before the accelerator has been demonstrated for several negative ion isobar systems with a prototype RFQ system incorporated into the AMS system at IsoTrace Laboratory, Canada (Ontario, Toronto). Requisite for any such RFQ system applied to very rare isotope analysis is large transmission of the analyte ion. This requires proper phase-space matching between the RFQ acceptance and the ion beam phase space (e.g. 35 keV, ${\varphi}3mm$, +-35 mrad), and the ability to control the average ion energy during interactions with the gas. A segmented RFQ instrument is currently being designed at Korea Institute for Science and Technology (한국과학기술연구원, KIST). It will consist of: a) an initial static voltage electrode deceleration region, to lower the ion energy from 35 keV down to ＜40 eV at injection into the first RFQ segment; b) the segmented quadrupole ion-gas interaction region; c) a static voltage electrode re-acceleration region for ion injection into a tandem accelerator. Design considerations and modeling will be discussed. This system should greatly lower the detection limits of the 6 MV AMS system currently being commissioned at KIST. As an example, current detection sensitivity of 41Ca/Ca is limited to the order of 10^-15 while the 41Ca/Ca abundance in modern samples is typically 41Ca/Ca~10^-14 - 10^-15. The major atomic isobaric interference in AMS is 41K. Proof-of-principal work at IsoTrace Lab. has demonstrated that a properly designed system can achieve a relative suppression of KF3-/41CaF3- ＞4 orders of magnitude while maintaining very high transmission of the 41CaF3- ion. This would lower the 41Ca detection limits of the KIST AMS system to at least 41Ca/Ca~10^-19. As Ca is found in bones and shells, this would potentially allow direct dating of valuable anthropological archives and archives relevant to our understanding of the most pronounced climate change events over the past million years that cannot be directly dated with the presently accessible isotopes.

• Neonatal Medicine
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• v.18 no.2
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• pp.370-373
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• 2011

Citrin deficiency caused by the SLC25A13 gene mutations is associated with both neonatal-onset type II citrullinemia (CTLN2), also known as neonatal intrahepatic cholestasis caused by citrin deficiency and adult-onset CTLN2. Neonatal-onset CTLN2 is an autosomal recessive disorder characterized by poor growth, intrahepatic cholestasis, and increased serum citrulline. A 16-days old infant with hyperammonemia was referred for evaluation of increased plasma citrulline diagnosed using tandem mass spectrometry. Blood amino acid analysis showed significant elevation of citrulline. Mild elevation in serum galactose levels had been found. DNA analysis of the SLC25A13 gene in this patient showed two novel compound heterozygous mutations, c.221C>T in exon4 and c.1645C in exon16 (p.[Ser74Phe]+[Gln549X]). We suggest that infants with a high serum citrulline level on a tandem mass screening test are candidates for gene analysis and blood amino acid analysis for neonatal-onset CTLN2.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.133.2-134
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• 2003

2-Methylaminoethyl-4, 4'-dimethoxy-5, 5', 6.6 -dimethylenedioxybiphenyl-2'-carboxy-2-carboxylate (DDB-S), a synthetic compound derived from DDB, has been known to protect liver against carbon tetrachloride-, D-galactosamine-, thioacetamide-, and prednisolone-induced hepatic injury in experimental animals. The metabolism of this compound has been assessed in rats by using liquid chromatography/electrospray tandem mass spectrometry (LC/MS/MS) method. (omitted)

• Analytical Science and Technology
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• v.28 no.6
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• pp.460-466
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• 2015

An isotope dilution liquid chromatography tandem mass spectrometry was developed as a primary method for the quantitative analysis of cholesterol in infant formula. Cholesterol-d₄ was used as an internal standard and spiked into the infant formula sample. In order to release cholesterol out of cholesteryl ester, which is cholesterol bound to fatty acids in infant formula, saponification was carried out. Saponification conditions were optimized with heating temperature, reaction time and the concentration of KOH. The optimum conditions were as follows; heating temperature was 70 ℃, reaction time was 180 min and the concentration of KOH was 0.8 mL of 8 M KOH for about 0.1 g infant formula sample. Extraction of cholesterol out of sample solution was carried out with hexane uisng liquid-liquid extraction. Chromatographic analysis was carried out using Phenomenex Kinetex C₁₈ column. Mobile phase was 0.1% acetic acid in methanol/water (v/v, 99/1) and flow rate was 0.3 mL/min. Cholesterol and cholesterol-d₄ were monitored at mass transfer m/z 369/259 and 373/263 respectively. Reproducibility of the method was evaluated to be 0.23% of the measurement result. The expanded uncertainty of the measurement result of cholesterol in infant formula was approximately 1.9% at a 95% confidence level. NIST standard reference material having certified values of cholesterol in infant formula, was analyzed in order to verify this method. The ID-LC/MS/MS results were well agreed with the certified values of NIST SRM within the uncertainty.

• Journal of Biomedical and Translational Research
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• v.19 no.4
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• pp.130-139
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• 2018

This study aimed to analyze a high-performance liquid chromatography (HPLC) separation using a pentafluorophenyl column of parent drug hydroxychloroquine (HCQ) and its active metabolite, desethylhydroxchloroquine (DHCQ) applying to determine bioequivalence of two different formulations administered to patients. A rapid, simple, sensitive and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for bioanalysis of HCQ and its metabolite DHCQ in human whole blood using deuterium derivative $hydroxychloroquine-D_4$ as an internal standard (IS). A triple-quadrupole mass spectrometer was operated using electrospray ionization in multiple reaction monitoring (MRM) mode. Sample preparation involves a two-step precipitation of protein techniques. The removed protein blood samples were chromatographed on a pentafluorophenyl (PFP) column ($50mm{\times}4.6mm$, $2.6{\mu}m$) with a mobile phase (ammonium formate solution containing dilute formic acid) in an isocratic mode at a flow rate of 0.45 mL/min. The standard curves were found to be linear in the range of 2 - 500 ng/mL for HCQ; 2 - 2,000 ng/mL for DHCQ in spite of lacking a highly sensitive MS spectrometry system. Results of intra- and inter-day precision and accuracy were within acceptable limits. A run time of 2.2 min for HCQ and 2.03 min for DHCQ in blood sample facilitated the analysis of more than 300 human whole blood samples per day. Taken together, we concluded that the assay developed herein represents a highly qualified technology for the quantification of HCQ in human whole blood for a parallel design bioequivalence study in a healthy male.

• Korean Journal of Pharmacognosy
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• v.46 no.4
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• pp.352-364
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• 2015

The aim of this study was to quantitatively analyze for quality assessment of eighteen marker compounds, including homogentisic acid, 3,4-dihydroxybenzaldehyde, spinosin, liquiritin, hesperidin, ginsenoside Rg1, liquiritigenin, ginsenoside Rb1, glycyrrhizin, 6-gingerol, atractylenolide III, honokiol, costunolide, dehydrocostuslactone, atractylenolide II, nootkatone, magnolol, and atractylenolide I, in Hyangsayukgunja-tang using an ultra-performance liquid chromatography-electrospray ionization-mass spectrometer. The column for separation of eighteen marker components were used a UPLC BEH $C_{18}$ analytical column ($2.1{\times}100mm$, $1.7{\mu}$) and kept at $45^{\circ}C$ by gradient elution with 0.1% (v/v) formic acid in water and acetonitrile as mobile phase. The flow rate and injection volume were 0.3 mL/min and $2.0{\mu}l$, respectively. The correlation coefficient of all marker compounds was ${\geq}0.9914$, which means good linearity, within the test ranges. The limits of detection and quantification values of the all analytes were in the ranges 0.04-1.11 and 0.13-3.33 ng/mL, respectively. As a result, five compounds, homogentisic acid, 3,4-dihydroxybenzaldehyde, spinosin, liquiritigenin, and atractylenolide I, in this sample were not detected and the amounts of the 13 compounds except for the 5 compounds were $8.10-6736.37{\mu}g/g$ in Hyangsayukgunja-tang extract.

• Korean Journal of Pharmacognosy
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• v.47 no.1
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• pp.92-101
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• 2016

In this study, an ultra-performance liquid chromatography-electrospray ionization-mass spectrometry (UPLC-ESI-MS/MS) method was established for simultaneous determination of the 25 marker components, including chlorogenic acid, gallic acid, oxypaeoniflorin, homogentisic acid, methyl gallate, caffeic acid, 3,4-dihydroxybenzaldehyde, paeoniflorin, albiflorin, liquiritin, nodakenin, ferulic acid, ginsenoside Rg1, liquiritigenin, coumarin, cinnamic acid, benzoylpaeoniflorin, ginsenoside Rb1, cinnamaldehyde, paeonol, glycyrrhizin, 6-gingerol, evodiamine, rutecarpine, and spicatoside A in traditional Korean formula, Onkyung-tang. All analytes were separated on a Waters Acquity UPLC BEH $C_{18}$ analytical column ($2.1{\times}100mm$, $1.7{\mu}m$) at $45^{\circ}C$ using a mobile phase of 0.1% (v/v) formic acid in water and acetonitrile with gradient elution. The MS analysis was carried out using a Waters ACQUITY TQD LC-MS/MS coupled with an electrospray ionization (ESI) source in the positive and negative modes. The flow rate and injection volume were 0.3 mL/min and $2.0{\mu}L$, respectively. The correlation coefficient of all analytes in the test ranges was greater than 0.98. The limits of detection and quantification values of the 25 marker compounds were in the ranges 0.03-19.43 and 0.09-58.29 ng/mL, respectively. As a result, methyl gallate, 3,4-dihydroxybenzaldehyde, evodiamine, and rutecarpine were not detected in this sample and the concentrations of the 21 compounds except for the above 4 compounds were $33.09-3,496.32{\mu}g/g$ in Onkyung-tang decoction. Among these compounds, paeonol was detected at the highest amount as a $3,496.32{\mu}g/g$.

• Journal of Ginseng Research
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• v.32 no.4
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• pp.390-396
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• 2008

For evaluating the quality of ginseng, simple and fast analysis methods are needed to determine the ginsenoside content of the ginseng products. The aim of this study was therefore to optimize conditions for fast analysis of the ginsenosides, the active ingredients in extracts of Korean red ginseng. When tandem HPLC mass spectrometry (HPLC-MS/MS) was used, four forms of ginsenoside, Rb1, Rb2, Rc, and Re, were readily separated in seven minutes using a gradient mobile phase (acetonitrile and water containing acetic acid). This is the shortest separation time reported among the studies of major ginsenoside analysis. When gradient HPLC with UV detection was used, the detection limit was high, but separation of these four ginsenosides required 25 minutes using acetonitrile and water containing formic acid as a mobile phase. HPLC-MS/MS was able to separate ginsenoside Rg1 easily regardless of the mobile phase condition, but the HPLC-UV could not separate Rg1 because acetonitrile concentration in the mobile phase had to be maintained below 20%. Ginsenoside peaks were clearer and had more sensitive detection limits when Korean red ginseng extract was analyzed by the HPLC-MS/MS, but the UV detection was useful for chromatographic fingerprinting of all four major ginsenosides of the extract: Rb1, Rb2, Rc, and Re. Extracts were found to contain 2.17 mg, 1.51 mg, 1.29 mg, and 0.46 mg of ginsenoside Rb1, Rb2, Rc, Re, respectively, per gram weight. The ratios of each ginsenoside in the extracts were 1.0 : 0.7 : 0.6 : 0.2, respectively. Taken together, the results indicate that HPLC-MS/MS spectrometry could be the most useful method for rapid analysis of even small amounts of major ginsenosides, while HPLC with UV detection could also be used for rapid analysis of major ginsenosides and for quality control of ginseng products.