• Title/Summary/Keyword: Optical purity

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Optical Purity Determination of (S)-Ibuprofen in Tablets by Achiral Gas Chromatography

  • Paik, Man-Jeong;Kim, Kyoung-Rae
    • Archives of Pharmacal Research
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    • v.27 no.8
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    • pp.820-824
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    • 2004
  • An optical purity test was indirectly performed on (S)-ibuprofen as its diastereomeric (R)-(+)-1-phenylethylamide derivative using achiral gas chromatography (GC). The method for the determination of trace (R)-ibuprofen (optical impurity), within the range 1.0 to 50 ng, from a racemic ibuprofen standard was linear (r=0.9997) with acceptable precision (% $RSD{\leq}5.3$) and accuracy (% RE=0.7~-3.9). Similar results were obtained with the method validation for the quantification of (S)-ibuprofen within the range 0.1 to 2.0 $\mu\textrm{g}$ using a (S)-ibuprofen stan-dard. When applied to seven different commercial (S)-ibuprofen products, their optical purities (98.7~99.1%) were determined with good precision (% $RSD{\leq}4.0$).

Control of Hydrolytic Degradation of Polylactide Mixtures Using Optical Isomers (광학이성질체를 이용한 폴리락타이드 혼합물의 가수분해성 조절)

  • Lee, Won-Ki
    • Polymer(Korea)
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    • v.36 no.3
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    • pp.309-314
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    • 2012
  • To control degradation rate of biodegradable poly(lactide)s (PLA), the stereochemical PLAs with different ratios of $d$-lactide and $l$-lactide units were synthesized by the ring open polymerization and a degradation behavior was measured by a Langmuir film balance. Degradation rates of mixture monolayers on alkaline subphase were investigated as a function of optical purity of mixture component, 100, 99, 97 and 95%. As increasing their optical purity, melting temperatures of mixtures from stereocomplexation increased. The degradation rate of mixture monolayer with 100% optical purity was much slower than that of each homopolymer one and the others showed 2 step degradation behaviors. In the first step, the degradation which is faster than that of each homopolymer occurs in the uncomplexed region, and secondly, the degradation occurred in the complexed region which showed similar degradation rate to that of 100% optical purity. These results indicate that the alkaline degradation of stereochemical PLAs could be controlled by stereochemistry and stereocomplexation between enantiomer PLAs.

1Determination of optical purity of N-acetyl-1-naphthylethylamine by chiral chromatography and NMR spectroscopy (키랄 크로마토그래피와 NMR 분광법에 의한 N-acetyl-1-naphthylethylamine의 광학순도 측정)

  • Jeong, Young-Han;Ryoo, Jae-Jeong
    • Analytical Science and Technology
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    • v.23 no.1
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    • pp.97-101
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    • 2010
  • (R)-N-3,5-dinitrobenzoyl (DNB) phenylglycinol derived chiral selector was used as a HPLC chiral stationary phase (CSP) for the resolution of racemic N-acylnaphthylalkylamines. In this study, determination of optical purity was performed by both chiral chromatography and NMR spectroscopy by using the (R)-phenylglycinol derived chiral selector. The data of accuracy and precision of each optical purity value are calculated from the results of NMR and HPLC experiments by comparing with true value. Average error of the NMR method was +2.2% with average RSD of 4.54%, while that of HPLC method was -3.5% with average RSD of 3.23%.

Monitoring of the Optical Purity for Levothyroxine Sodium in Pharmaceuticals Using Crown Ether Derived Chiral Columns (크라운 에테르에서 유도된 키랄 컬럼을 사용한 레보티록신 나트륨 의약품의 광학순도 모니터링)

  • Jeon, So-Hee;Lee, Won-Jae
    • KSBB Journal
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    • v.25 no.5
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    • pp.449-452
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    • 2010
  • L-Thyroxine possessing a chiral center, the naturally occurring thyroid hormone has been used for the treatment of thyroid dysfunctions and marketed as levothyroxine (L-thyroxine) sodium salt. In this study, after extraction of levothyroxine tablet as a pre-treatment process, direct enantiomer separation of thyroxine on crown ether derived chiral columns for determination of optical purity was performed using reversed mobile phase with acid additive. The chromatographic method developed in this study was applied in the determination of optical purity of several current domestic and foreign commercialized levothyroxine tablets. Optical purity values of these commercialized L-thyroxine sodium tablets except one were higher than 99 percents.

Measurement of optical purity for commercial naproxen by chiral HPLC (키랄 크로마토그래피에 의한 시판되는 나프록센의 광학순도 측정)

  • Yu, Jeong-Jae;Lee, Won-Doo;Ryoo, Jae-Jeong
    • Analytical Science and Technology
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    • v.24 no.5
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    • pp.360-367
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    • 2011
  • Optical purities of 10 commercialized naproxens prepared from eight Korean drug companies were examined by an optimized chiral HPLC condition. The Chiralcel OD-H column and ChiralHyun-LE(S)-1 column were used as chiral stationary phases and the mixed eluent of hexane/isopropanol/acetic acid as 100:2.85:0.1 was used as a mobile phase for effective enantioseparation. Optical purity values of most samples were higher than 97 percents, only one of them was about 95 percents. The average relative standard deviation of them appeared very small (0.034%).

Studies on the Determination of Hyoscine-N-butylbromide by ORD and CD(I) (ORD 및 CD에 의한 Tropane Alkaloid의 정량에 관한연구(I) - Hyoscine-N-butylbromide의 정량)

  • 백남호;박만기;염정록;김예숙
    • YAKHAK HOEJI
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    • v.23 no.3_4
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    • pp.129-132
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    • 1979
  • The ORD and CD for hyoscine-N-butylbromide present curves of negative Cotton effect in 190-250nm region. The values of .alpha./sub 232/ .alpha./sub 208/, vertical bar .alpha./sub 232/ vertical bar + vertical bar .alpha./sub 208/ and .theta./sub 221.5/ have linearities in the range of lower concentration (hyoscine-N-butylbromide 0.01-0.1w/v%). It is possible to determine the optical purity of hyoseine-N-butylbromide by using these linearities. This experiment is extremely simple and less time-consuming than other methods for estimating optical purity.

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Chiral Purity Test of Metoprolol Enantiomer After Derivatization with (-)-Menthyl Chloroformate by Reversed-Phase High Performance Liquid Chromatography

  • Kim, Kyeong-Ho;Choi, Pok-Wha;Hong, Seon-Pyo;Kim, Hyun-Ju
    • Archives of Pharmacal Research
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    • v.22 no.6
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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.

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Luminescence Properties of Phosphor Layer with Discharge Conditions in AC PDP (교류형 플라즈마 디스플레이 패널의 방전 조건변화에 따른 형광막의 발광특성)

  • Jang, Sang-Hun;Tae, Heung-Sik;Choe, Gyeong-Cheol
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.48 no.10
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    • pp.704-709
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    • 1999
  • The optical properties such as luminance and color coordinates for phosphor layer were studied with applied voltage and gas pressure, Xe mixing ratio, frequency using He and Xe mixing gas in chamber like AC PDP. The luminance of red phosphor layer at constant pressure(300Toor) is increased with increasing voltage, but color purity is not varied. The luminance of red phosphor layer at constant voltage(280V)is decreased with increasing pressure, but the color purity is not varied. But the luminance is increased with increasing Xe mixing ratio at constant pressure(200Toor). And also the color purity is improved by this process. The luminance is increased up to 40kHz, but the color purity with frequency is not varied.

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