Enantiomers high-performance liquid

Most amino acids have a chiral center at the alpha position, resulting in L- and D-enantiomers. High-performance liquid chromatography is the most widely used technique for the separation of amino acid enantiomers. For that purpose, various chiral deiivatizing reagents and chiral stationary phases are frequently used. The following topics are t)rpical examples of the LC separation and determination of amino acid enantiomers. 

L. Liu, H. Cheng, J. J. Zhao and J. D. Rogers, Determination of montelukast (MK-0476) and its 5-enantiomer in human plasma by stereoselective high performance liquid cliromatography with column-switching , ]. Pharm. Biomed. Anal. 15 631-638 (1997). 

C. L. Hsu and R. R. Walters, Assay of the enantiomers of ibutilide and artilide using solid-phase extraction, derivatization and achhal-cliiral column-switcliing high-performance liquid cliromatography , J. Chromatogr. B 667 115-128 (1995). 

C.-Y. Hsieh and J.-D. Huang, Two-dimensional high-performance liquid cliromato-grapliic method to assay p-hydroxyphenylphenylhydantoin enantiomers in biological... 

Y. Oda, N. Asakawa, Y. Yoshida and T. Sato, On-line determination and resolution of the enantiomers of ketoprofen in plasma using coupled achiral-cliiral high-performance liquid chromatography , 7. Pharm. Biomed. Anal. 10 81-87 (1992). 

H. Fujimoto, I. Nishino, K. Ueno and T. Umeda, Determination of the enantiomers of a new 1,4-dihydropyridine calcium antagonist in dog plasma achiral / chiral coupled high performance liquid cliromatography with electrochemical detection , 7. Pharm. Sci. 82 319-322(1993). 

D. Masurel and F W. Wainer, Analytical and preparative high-performance liquid cliromatographic separation of the enantiomers of ifosfamide, cyclophosphamide and ti ofosfamide and their determination in plasma , 7. Chromatogr. 490 133-143 (1989). 

Despite the difficulties caused by the rapidly expanding literature, the use of chiral stationary phases (CSPs) as the method of choice for analysis or preparation of enantiomers is today well established and has become almost routine. It results from the development of chiral chromatographic methods that more than 1000 chiral stationary phases exemplified by several thousands of enantiomer separations have been described for high-performance liquid chromatography (HPLC). 

Capillary electrophoresis employing chiral selectors has been shown to be a useful analytical method to separate enantiomers. Conventionally, instrumental chiral separations have been achieved by gas chromatography and by high performance liquid chromatography.127 In recent years, there has been considerable activity in the separation and characterization of racemic pharmaceuticals by high performance capillary electrophoresis, with particular interest paid to using this technique in modem pharmaceutical analytical laboratories.128 130 The most frequently used chiral selectors in CE are cyclodextrins, crown ethers, chiral surfactants, bile acids, and protein-filled... 

Chu, Y.Q., Wainer, I.W. (1988). The measurement of warfarin enantiomers in serum using coupled achiral/chiral high performance liquid chromatography. Pharm. Res. 5, 680-683. 

Clark, B.J., Hamdi, A., Berrisford, R.G., Sahanathan, S., Meams, AJ. (1991). Reversed-phase and chiral high-performance liquid chromatographic assay of hupivacaine and its enantiomers in clinical samples after continuous extraplural infusion. J. Chromatogr. 553,383-390. 

Corlett, S.A., Chrystyn, H. (1996). High-Performance liquid chromatographic determination of the enantiomers of cyclophosamide in semm. J. Chromatogr. B 682, 337-342. 

Desai,M.J., Armstrong, D.W. (2004). Analysis of native amino acid and peptide enantiomers by high-performance liquid chromatography/atmospheric pressure chemical ionization mass spectrometry. J. Mass. Spec. 39, 177-187. 

Guo, X., Fukushima, T., Li, F., Imai, K. (2002). Determination of fluoxetine enantiomers in rat plasma by precolumn fluorescence derivatization and column-switching high-performance liquid chromatography. Analyst 127, 480-484. 

Kim, K.H., Kim, H.J., Hong, S.-R, Shin, S.D. (2000a). Determination of tertbutaline enantiomers in human plasma by coupled achiral-chiral high performance liquid chromatography. Arch. Pharm. Res. 23, 441-445. 

Oda, Y., Asakawa, N., Kajima, T., Yoshida, Y., Sato, T. (1991). Column-switching high-performance liquid chromatography for online simultaneous determination and resolution of enantiomers of verapamil and its metabolites. Pharm. Res. 8, 997-1001. 

Soltes, L., Sebille, B. (1997). Reversible binding interactions between the tryptophan enantiomers and albumins of different animal species as determined by novel high performance liquid chromatographic methods an attempt to localize the d- and L-tryptophan binding sites on the human serum albumin polypeptide chain by using protein fragments. Chirality 9, 373-379. 

Tanaka, M., Yamazaki, H. (1996). Direct determination of pantoprazole enantiomers in human serum by reverse-phase high-performance liquid chromatography using a cellulose-based chiral stationary phase and column-switching system as a sample cleanup procedure. Anal. Chem. 68, 1513-16. 

Walters, R.R., Buist, S.C. (1998). Improved enantioselective method for the determination of the enantiomers of reboxetine in plasma by solid-phase extraction, chiral derivitization, and column-switching high-performance liquid chromatography with fluorescence detection. J. Chromatogr. A 828, 167-176. 

Acidimetric, spectrophotometric, and high-performance liquid chromatography (HPLC) assays were developed for the determination of 2,3,5,6,7,8-hexahydro-l//-pyrido[l,2-c]pyrimidine-l,3-diones 100 <1998APH193>. Its solubility properties were also characterized. Resolution of the enantiomers of 4-phenyl-2- 4-[4-(2-pyrimidinyl)piperazinyl]-butyl perhydropyrido[l,2-r-]pyrimidine-l,3-dione was achieved on heptakis(2-A V-dimethylcarbamoyl)-P-... 

Enantiomers of the 8,9-dichloro-2,3,4,4 ,5,6-hexahydro-177-pyrazino[l,2-tf]quinoxalin-5-one (structure 249 Rz = R3 = Cl R1 = R4 = H) could be separated by normal-phase, chiral high-performance liquid chromatography (HPLC) with increased retention and separation factors if ethoxynonafluorobutane was used as solvent, instead of -hexane <2001JCH(918)293>. 

The above chemistry has been applied to the synthesis of a series of derivatives which show activity against animal parasites. In order to confirm further the stmcture and configuration of the most active enantiomer of one of these compounds, the enantiomers were separated by chiral high-performance liquid chromatography (HPLC), and single crystal X-ray diffraction of a 2 1 CuCl2 complex was carried out <2005BML2375>. 

Aboul-Enein and Ali [78] compared the chiral resolution of miconazole and two other azole compounds by high performance liquid chromatography using normal-phase amylose chiral stationary phases. The resolution of the enantiomers of ( )-econazole, ( )-miconazole, and (i)-sulconazole was achieved on different normal-phase chiral amylose columns, Chiralpak AD, AS, and AR. The mobile phase used was hexane-isopropanol-diethylamine (400 99 1). The flow rates of the mobile phase used were 0.50 and 1 mL/min. The separation factor (a) values for the resolved enantiomers of econazole, miconazole, and sulconazole in the chiral phases were in the range 1.63-1.04 the resolution factors Rs values varied from 5.68 to 0.32. 

Dondi M, Flieger M, Olsovska J, Polcaro CM, Sinibaldi M (1999) High-performance liquid chromatography study of the enantiomer separation of chrysanthemic acid and its stationary phase. J Chromatogr A 859 133-142... 

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