• 분석과학
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• 제33권1호
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• pp.1-10
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• 2020

Alpha lipoic acid, an antioxidant, is widely used for treatment of various diseases. It is a racemic mixture, with R-(+)-α lipoic acid exhibiting greater potency, bioavailability, and effectiveness than those of the S-form. Thus, selective R-(+)-α lipoic acid has been recently used in various applications, necessitating the development of a method to test the enantiomeric impurity in R-(+)-α lipoic acid. We developed a simple and fast high-performance liquid chromatography method using a new immobilized amylose-based chiral column (Chiralpak IA-3). Design of experiment was applied to accurately predict the effects and interactions among various factors affecting the analytical parameters and to optimize the chromatographic conditions. This optimized method could completely separate the two enantiomer peaks with a resolution > 1.8 within a short running time (9 min). Then, the optimized method was validated according to the guidelines of the International Conference on Harmonization and applied for quantification of S-(-)-α lipoic acid in some commercial R-(+)-α lipoic acid tromethamine raw material. Our results suggested that the developed method could be used for routine quality control of R-(+)-α lipoic acid products.

• Bulletin of the Korean Chemical Society
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• 제27권4호
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• pp.524-528
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• 2006

Three different style capillary columns, a packed capillary with temporary quartz wool frit, a packed capillary with immobilized frit, and an immobilized packed-capillary, were easily prepared with a commercially available (S)-N-(3,5-dinitro-benzoyl)leucine-N-phenyl-N-alkylamide derived chiral stationary phase. Liquid chromatographic chiral separations of some racemic amino acid derivatives on these columns were performed and the results were compared to each other. The packed capillary with immobilized frit showed some merits in chiral chromatography.

• KSBB Journal
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• 제27권3호
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• pp.167-171
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• 2012

A convenient liquid chromatographic enantiomer separation of several ${\alpha}$-amino acid esters as benzophenone Schiff base derivatives on covalently immobilized chiral stationary phases (CSPs) derived from polysaccharide derivatives was developed. The benzophenone imine derivatives of ${\alpha}$-amino acid esters were readily prepared by stirring benzophenone imine and the ${\alpha}$-amino acid ester hydrochloride salts in 2-propanol. The chromatographic conditions used on all CSPs were 0.5% or 5% 2-propanol/hexane (V/V) as the mobile phases at 1 mL/min of flow rate and UV 254 nm detection. The performance of Chiralpak IC among all CSPs was superior to that of the other CSPs for resolution of benzophenone imine derivatives of ${\alpha}$-amino acid esters. It is expected that the developed analytical method will be useful for enantiomer resolution of other ${\alpha}$-amino acid esters as benzophenone Schiff base derivatives.

• KSBB Journal
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• 제31권3호
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• pp.186-191
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• 2016

A liquid chromatographic method for the enantiomer separation of fluoxetine was performed using covalently bonded and coated type polysaccharide-derived chiral stationary phases (CSPs). The degree of enantioseparation is affected by the used CSPs and mobile phases. The performance of Chiralpak IC was superior to the other CSPs used in this study. Out of various solvent composition and additives, the greatest separation and resolution was observed using Chiralpak IC with mobile phase of 2-propanol in hexane with diethylamine as an additive. Semi-preparative separation of fluoxetine was performed on the analytical Chiralpak IC column to obtain (R)- and (S)-fluoxetine enantiomer with high chemical and optical purity. From the overall study, the developed liquid chromatographic method on polysaccharide-derived CSPs is expected to be very useful for the enantiomer separation of fluoxetine.

• Bulletin of the Korean Chemical Society
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• 제32권12호
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• pp.4415-4418
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• 2011

• Natural Product Sciences
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• 제6권1호
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• pp.20-24
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• 2000

The enantiomers of higenamine were directly separated by high performance liquid chromatography using a chiral stationary phase and detected by UV. The R- and S-isomers of higenamine were eluted at the retention time of 22 min and 27 min, respectively. Higenamine was determined to be present as R-(+)-enantiomer not only in the embryo of Nelumbo nucifera, from which the separation of R-(+)-higenamine was reported, but also in various Aconite roots, from which higenamine was separated as optically inert racemic mixtures.

• Bulletin of the Korean Chemical Society
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• 제24권2호
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• pp.239-242
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• 2003

• Archives of Pharmacal Research
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• 제23권2호
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• pp.178-181
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• 2000

In order to study the simultaneous determination of (+)- and (-)-cetirizine in human urine we have developed a chiral separation method by HPLC. A chiral stationary phase of $\alpha$$_1$-acidglycoprotein, the AGP-CSP was used to separate the enantiomers. The pH of the phosphate buffer, as well as the content of the organic modifier in the mobile phase, markedly affected the chromatographic separation of (+)- and (-)-cetirizine. A mobile phase of 10 m㏖/1 phosphate buffer (pH 7.0)-acetonitrile (95 : 5, v/v) was used for the urine assays. Ultraviolet absorption was monitored at 230nm and roxatidine was employed as the internal standard for quantification. (+)-Cetirizine, (-)-cetirizine and the internal standard were eluted at retention times of 12, 16, and 32 mins, respectively. The detection limit for cetirizine enantiomers was 400 ng/$m\ell$ of urine. A pharmacokinetic study was conducted with the help of 5 healthy female volunteers who were administered with a single oral dose of racemic cetirizine (20 mg). The peak area ratios provided by the cetirizine enantiomers were linear(r>0.997) over a concentration range of 2.5-200 ${\mu}g/ml$. The peak of the excreted cetirizine enantiomers appeared in the urine sample during the period of 1-2 hrs following the administration of the oral dose. The excreted level of (+)-cetirizine was slightly higher than (-)-cetirizine but the difference was not statistically significant. However, this method appears to have applications for enantioselective pharmacokinetic studies of racemic drugs.

• 대한화학회지
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• 제58권2호
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• pp.179-185
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• 2014

시판되는 (S)-naproxen을 강염기 조건에서 라세미화하였다. 라세미화된 naproxen 시료를 분석하여 (R)- 및 (S)-naproxen의 피이크 위치를 확인한 후, 2013년 국내에서 시판된 19개 naproxen의 광학순도를 키랄 HPLC로 조사하였다. Chiralcel OD-H 칼럼과 ChiralHyun-LE(S)-1 칼럼 및 LUX-Cellulose-1 칼럼을 키랄 정지상으로 사용하였고, hexane:isopropanol:acetic acid가 100:1:0.1로 혼합된 용액을 전개용매로 사용하여 흐름속도 1.0 mL/min에서 분석하였다. 각 시료를 최소 3회 이상 분석하여 얻은 평균값을 각각 계산하여 데이터로 이용하였고, 이들의 상대표준편차도 계산하여 그 값이 아주 작게 나타난 것을 확인하였다. 세 종류의 다른 칼럼에서 각각 측정한 광학순도 값이 서로 아주 유사한 값을 보여주었으며, 측정된 naproxen의 광학순도는 이들의 광학순도 데이터가 처음 보고된 2010년 시료의 광학순도 평균값인 98.17%에 비해 높은 99.32%를 보였다.

• 대한화학회지
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• 제34권1호
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• pp.76-84
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• 1990

키랄이동상 첨가법으로 단실아미노산의 광학이성질체들을 분리했다. 두 가지의 xylenyl-L-proline 이성질체를 합성하고 이것을 구리(Ⅱ)킬레이트로 만들어 이동상에 첨가하여 단실아미노산의 광학 이성질체를 분리했다. 이 아미노산에 대한 용리거동은 benzyl-L-proline의 구리착물을 사용했을 때와 유사했다. 이동상에서 유기용매의 조성, 완충용액의 농도 및 pH에 대한 효과도 조사 검토했다. 분리메카니즘은 리간드 교환반응의 시스-트란스 효과의 삼성분착물과 정지상간의 소수성 상호작용으로 설명할 수 있었다.