• Bulletin of the Korean Chemical Society
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• 제25권1호
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• pp.109-114
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• 2004

A sensitive method for quantitation of glimepiride in human plasma has been established using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI/MS/MS). Glipizide was used as an internal standard. Glimepiride and internal standard in plasma sample was extracted using diethyl etherethyl acetate (1 : 1). A centrifuged upper layer was then evaporated and reconstituted with the mobile phase of acetonitrile-5 mM ammonium acetate (60:40, pH 3.0). The reconstituted samples were injected into a $C_{18}$ reversed-phase column. Using MS/MS in the multiple reaction monitoring (MRM) mode, glimepiride and glipizide were detected without severe interference from human plasma matrix. Glimepiride produced a protonated precursor ion ([M+H]$^+$) at m/z 491 and a corresponding product ion at m/z 352. And the internal standard produced a protonated precursor ion ([M+H]]$^+$) at m/z 446 and a corresponding product ion at m/z 321. Detection of glimepiride in human plasma by the LC-ESI/MS/MS method was accurate and precise with a quantitation limit of 0.1 ng/mL. The validation, reproducibility, stability, and recovery of the method were evaluated. The method has been successfully applied to pharmacokinetic studies of glimepiride in human plasma.

• Journal of Pharmaceutical Investigation
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• 제40권2호
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• pp.101-107
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• 2010

A rapid and sensitive reversed-phase high performance liquid chromatography (HPLC) method was developed for the determination of N-(-4-Chlorophenyl)-6-hydroxy-7-methoxy-2-chromanecarboxamide (KAL-1120), a novel anti-inflammation agent, in the rat plasma. The method was applied to analyze the compound in the biological fluids such as bile, urine and tissue homogenates. After liquid-liquid extraction, the compound was analyzed on an HPLC system with ultraviolet detection at 275 nm. HPLC was carried out using reversed-phase isocratic elution with a $C_{18}$ column, a mobile phase of a mixture of acetonitril (40 v/v%) at a flow rate of 1.0 mL/min. The chromatograms showed good resolution and sensitivity and no interference of plasma. The calibration curve for the drug in plasma was linear over the concentration range of 0.05-50 ${\mu}g$/mL. The intra- and inter-day assay accuracies of this method ranged from 0.06% to 9.33% of normal values and the precision did not exceed 6.28% of relative standard deviation. The plasma concentration of KAL-1120 decreased to below the quantifiable limit at 1.5 hr after the i.v. bolus administration of 2-10 mg/kg to rats ($t_{1/2,({\alpha})}$ and $t_{1/2,({\beta})$ of 2.15 and 26.7 min at a dose of 2 mg/kg, 3.91 and 33.0 min at a dose of 10 mg/kg, respectively). The steady-state volume of distribution ($V_{dss}$) and the total body clearance ($CL_t$) were not significantly altered in rats given doses from 2 to 10 mg/kg. Of the various tissues tested, KAL-1120 was mainly distributed in the lung and heart after i.v. bolus administration. KAL-1120 was detected in the bile by 30 min after its i.v. bolus administration. However, the concentration in the urine after i.v. bolus administration became too low to measure, suggesting that KAL-1120 is mostly excreted in the bile. In conclusion, this analytical method was suitable for the preclinical pharmacokinetic studies of KAL-1120 in rats.

• 생명과학회지
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• 제26권3호
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• pp.296-301
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• 2016

메기(Silurus asotus)의 껍질로부터 항균성 펩타이드를 정제하였다. 메기 껍질의 산 추출물은 단계적 농도구배조건으로 Sep-Pak C₁₈에 의해 부분적으로 정제되었으며, 그 중에서 특히 60% 메탄올 분획(RM60)이 Escherichia coli D31에 대해 가장 좋은 항균활성을 나타내었다. 이 RM60을 사용하여 이온교환 및 5단계의 연속적인 역상 HPLC로 정제하였다. 정제된 펩타이드의 분자량과 아미노산 서열분석은 MALDI-TOF MS와 에드만 분해법으로 분석하였다. 이 펩타이드의 분자량은 약 4182.1 [M+H]⁺이었으며, 분석된 이 물질의 부분적인 일차구조서열은 다음과 같다; PALXXKARREAKVKF. 이러한 결과는 메기의 껍질에서 존재하는 이 펩타이드가 메기의 껍질에서 반응하는 선천성 방어 시스템에서 중요한 역할을 하고 있다고 여겨진다.

• 생명과학회지
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• 제27권1호
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• pp.50-56
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• 2017

졸복(Takifugu pardalis)의 아가미로부터 항균성 펩타이드를 정제하였다. 졸복 아가미의 산 추출물은 Sep-Pak C18에 의해 부분적으로 정제되었으며, 60% 메탄올 분획(RM60)은 Bacillus subtilis KCTC 1021에 대해 높은 항균활성을 나타내었다. 이 RM60을 사용하여 이온교환을 포함한 5단계의 연속적인 HPLC로 정제하였다. 정제된 펩타이드의 분자량과 아미노산 서열분석은 MALDI-TOF MS와 에드만 분해법으로 분석하였다. 이 펩타이드의 분자량은 약 1171.6 Da이었으며, 분석된 이 물질의 부분적인 일차구조서열은 다음과 같다; STKEKAPRKQ. 이 물질과 기존에 알려진 항균성 펩타이드들과 유사성을 조사한 결과, 정제된 물질은 histone H3 계열의 N-말단 부분과 유사하였다. 이러한 결과로부터 정제된 펩타이드는 졸복에서 반응하는 선천성 방어 시스템에서 중요한 역할을 하고 있다고 여겨진다.

• Journal of Pharmaceutical Investigation
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• 제35권5호
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• pp.375-381
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• 2005

A rapid and specific high-performance liquid chromatographic method was developed and validated for the simultaneous determination of prostaglandin $E_{1}\;(PGE_{1})$ and prostaglandin $E_{1}$ ethyl ester $(PGE_{1}-EE)$ in hairless mouse skin homogenate. The sample treatment procedure involved deproteination and precipitation by acetonitrile. $PGE_{1}$ and $PGE_{1}-EE$ in supernatant were separated in a reversed-phase C18 column without being interfered by other components present in hairless mouse skin homogenate. 9-Anthracenecarboxylic acid was used as an internal standard. The retention times of $PGE_{1}$, 9-anthracenecarboxylic acid and $PGE_{1}-EE$ were, 4.5, 9.5 and 18.0 min, respectively. The assay showed linearity from 1 to $40\;{\mu}g/ml$ for both $PGE_{1}$ and $PGE_{1}-EE$. Precision expressed as RSD ranged from 2.3 to 14.1 % for $PGE_{1}$ and 1.6 to 11.0% for $PGE_{1}-EE$. Accuracy ranged from 100.5 to 119.6 % for $PGE_{1}$ and from 98.0 to 103.7% for $PGE_{1}-EE$. This method was employed successfully to follow the time course of concentrations of $PGE_{1}$ and $PGE_{1}-EE$ in hairless mouse skin homogenate for stability study.

• Journal of Pharmaceutical Investigation
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• 제35권3호
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• pp.137-142
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• 2005

A rapid, selective and sensitive reversed-phase HPLC method for the determination of glipizide in human serum was validated and applied to the pharmacokinetic study of glipizide. Glipizide and internal standard, tolbutamide, were extracted from human serum by liquid-liquid extraction with benzene and analyzed on a Nova Pak $C_{18}\;60{\AA}$ column with the mobile phase of acetonitrile-potassium dihydrogen phosphate (10 mM, pH 3.5) (4:6, v/v). Detection wavelength of 275 nm and flow rate of 0.7 ml/min were fixed for the study. The assay robustness for the changes of mobile phase pH, organic solvent content, and flow rate was confirmed by $3^3$ factorial design using a fixed glipizide concentration (500 ng/ ml) with respect to its peak area and retention time. And also, the ruggedness of this method was investigated at three different laboratories using same quality control (QC) samples. This method showed linear response over the concentration range of 10-1000 ng/ml with correlation coefficient greater than 0.999. The lower limit of quantitation using 0.5 ml of serum was 10.0 ng/ml, which was sensitive enough for pharmacokinetic studies. The overall accuracy of the quality control samples ranged from 82.6 to 105.0% for glipizide with overall precision (% C.V.) being 1.13-13.20%. The percent recovery for human serum was in the range of 85.2 93.5%. Stability studies showed that glipizide was stable during storage, or during the assay procedure in human serum. The peak area and retention time of glipizide were not significantly affected by the changes of mobile phase pH, organic solvent content, and flow rate under the conditions studied. This method showed good ruggedness (within 15% C.V.) and was successfully used for the analysis of glipizide in human serum samples for the pharmacokinetic studies at three different laboratories, demonstrating the suitability of the method.

• Journal of Pharmaceutical Investigation
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• 제35권4호
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• pp.265-271
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• 2005

A rapid, selective and sensitive reversed-phase HPLC method for the determination of etodolac in human serum was developed, validated, and applied to the pharmacokinetic study of etodolac. Etodolac and internal standard, ibuprofen were extracted from human serum by liquid-liquid extraction with hexane/isopropanol (95:5, v/v) and analyzed on a Luna C18(2) column with the mobile phase of 1% aqueous acetic acid-acetonitrile (4:6, v/v). Detection wavelength of 227 nm and flow rate of 1.0 mL/min were fixed for the study. The assay robustness for the changes of mobile phase pH, organic solvent content, and flow rate was confirmed by $3^3$ factorial design using a fixed etodolac concentration $(1\;{\mu}g/mL)$ with respect to its peak area and retention time. And also, the ruggedness of this method was investigated at three different laboratories using same quality control (QC) samples. This method showed linear response over the concentration range of $0.05-40\;{\mu}g/mL$ with correlation coefficients greater than 0.999. The lower limit of quantification using 0.5 mL of serum was 0.05 ${\mu}g/mL$, which was sensitive enough for pharmacokinetic studies. The overall accuracy of the quality control samples ranged from 92.00 to 110.00% for etodolac with overall precision (% C.V.) being 1.08-10.11%. The percent recovery for human serum was in the range of 76.73-115.30%. Stability studies showed that etodolac was stable during storage, or during the assay procedure in human serum. The peak area and retention time of etodolac were not significantly affected by the changes of mobile phase pH, organic solvent content, and flow rate under the conditions studied. This method showed good ruggedness (within 15% C.V.) and was successfully used for the analysis of etodolac in human serum samples for the pharmacokinetic studies of orally administered Lodin XL tablet (400 mg as etodolac) at three different laboratories, demonstrating the suitability of the method.

• Journal of Pharmaceutical Investigation
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• 제35권6호
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• pp.423-429
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• 2005

A selective and sensitive reversed-phase HPLC method for the determination of fenoprofen in human serum was developed, validated, and applied to the pharmacokinetic study of fenoprofen calcium. Fenoprofen and internal standard, ketoprofen, were extracted from human serum by liquid-liquid extraction with diethyl ether and analyzed on a Luna C18(2) column with the mobile phase of acetonitrile-3 mM potassium dihydrogen phosphate (32:68, v/v, adjusted to pH 6.6 with phosphoric acid). Detection wavelength of 272 nm and flow rate of 0.25 mL/min were fixed for the study. The assay robustness for the changes of mobile phase pH, organic solvent content, and flow rate was confirmed by $3^{3}$ factorial design using a fixed fenoprofen concentration $(2\;{\mu}g/mL)$ with respect to its peak area and retention time. And also, the ruggedness of this method was investigated at three different laboratories using same quality control (QC) samples. This method showed linear response over the concentration range of $0.05-100\;{\mu}g/mL$ with correlation coefficients greater than 0.999. The lower limit of quantification using 1 mL of serum was $0.05\;{\mu}g/mL$, which was sensitive enough for pharmacokinetic studies. The overall accuracy of the quality control samples ranged from 92.27 to 109.20% for fenoprofen with overall precision (% C.V.) being 5.51-11.71 %. The relative mean recovery of fenoprofen for human serum was 81.7%. Stability (freeze-thaw, short and long-term) studies showed that fenoprofen was not stable during storage. But, extracted serum sample and stock solution were allowed to stand at ambient temperature for 12 hr prior to injection without affecting the quantification. The peak area and retention time of fenoprofen were not significantly affected by the changes of mobile phase pH, organic solvent content, and flow rate under the conditions studied. This method showed good ruggedness (within 15% C.V.) and was successfully used for the analysis of fenoprofen in human serum samples for the pharmacokinetic studies of orally administered Fenopron tablet (600 mg as fenoprofen) at three different laboratories, demonstrating the suitability of the method.

• Journal of Applied Biological Chemistry
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• 제50권4호
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• pp.244-248
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• 2007

The contents of total phenol and total flavonoid of artichoke (Cynara scolymus L.) were measured. The antioxidant activity of the artichoke was evaluated based on its potential as a scavenging the ABTS radical. These results showed the antioxidant activity of artichoke has a close relationship with the total flavonoid content. The compound showing antioxidant activity was isolated from the artichoke by repeated column chromatography and recrystallization. Based on the spectrometric studies, the compound was identified as 1,3-dicaffeoylquinic acid, known as cynarin. The content of cynarin from heads and leafs of the artichoke determined by $C_{18}$ reversed phase HPLC (high-performance liquid chromatography) coupled with photodiode array detector was 10.15 and 0.67 mg/g, respectively. This compound showed potent antioxidant activities against DPPH and ABTS radicals ($EC_{50}$ = 14.09 and 28.85 ${\mu}M$, respectively).

• 한국약용작물학회지
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• 제22권2호
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• pp.147-153
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• 2014

The Ponciri fructus immaturus (Poncirus trifoliata Rafinesque) has been used in oriental medicine for uterine contraction, stomachache, abdominal distension and cardiovascular diseases. Two main compounds, poncirin and naringin were successfully analyzed by high performance liquid chromatography (HPLC) and carried out method validation according to ICH guideline. A successful resolution and retention times were obtained with a $C_{18}$ reversed phase column, at an $1m{\ell}min^{-1}$ flow rate, with a gradient elution of a mixture of methanol, water and acetonitrile. Poncirin and naringin showed good linearity ($R^2$ > 0.999) in relatively wide concentration ranged. The recovery of each compound was 95.81 ~ 101.48% with R.S.D. values less than 1.0%. The application of ultrasound-assisted extraction was shown to be more efficient in extracting poncirin and naringin from Ponciri fructus immaturus. The predicted optimal poncirin and naringin yield were poncirin 2.15%, naringin 1.65% under an extraction temperature of $40^{\circ}C$, an extraction time of 10 min in a solvent of 70% methanol.