Vancomycin stationary phase

The column was 25 cm long, 4.6 mm I.D. and packed with Partisil 10. It is seen that linear curves were obtained for three different solutes and two different moderators in n-heptane. Scott and Beesley [14] obtained retention data for the two enantiomers, (S) and (R) 4-benzyl-2-oxazolidinone. The column chosen was 25 cm long, 4.6 mm I.D. packed with 5 mm silica particles bonded with the stationary phase Vancomycin (Chirobiotic V provided by Advanced Separations Technology Inc., Whippany, New Jersey). This stationary phase is a macrocyclic glycopeptide Vancomycin that has a molecular weight of 1449.22, and an elemental composition of 54.69% carbon. 

Biaryl structures are wide-spread in many of naturally occuring products including alkaloids, lignans, terpenes, flavonoids, tannins, as well as polyketides, coumarins, peptides, glycopeptides, etc. For example, vancomycin (1) is a basic structure of several related glycopeptide antibiotics [1] balhimycin, actinoidin A, ristocetin A, teicoplanin A2-2, complestatin, etc which are important in medicinal chemistry or as a HPLC chiral stationary phases (vancomycin) [2]. 

The chirobiotic chiral stationary phases (103,104) are based on macrocycHc antibiotics such as vancomycin (4) and teicoplanin (5). 

Vancomycin was the first macrocyclic antibiotic evaluated as selector for the synthesis of HPLC chiral stationary phases (CSPs) [7], along with rifamycin B (among ansamycins) and thiostrepton (among polypeptides). 

In an attempt to change and broaden the capabilities of the vancomycin CSP, the glycopeptide was derivatized with (R)- and (S )-(l-naphthylethyl) isocyanate (NEIC) and then bonded to a silica-gel support [48]. A variety of chiral compounds was tested on the two composite stationary phases and the results were compared with the ones obtained using the underivatized vancomycin CSP. The advantages of the NEIC derivatization were not as obvious or substantial as they were in the case of cyclodextrin phases [49]. Moreover, the exact chemical structures of the synthesized NEIC derivatives of vancomycin were not reported. 

In the case of vancomycin [72], an original study was performed to obtain a well-defined stationary phase structure, since it was reasonably assumed that the antibiotic is randomly linked to the silica by one or both of its amino groups, one belonging to the disaccharide portion (primary), and the other one to the heptapeptide core (secondary). Thus, alternate fluorenylmethyloxycarbonyl (FMOC)-amino-protected derivatives were prepared and immobilized in a packed column, and then vancomycin was recovered by cleavage of the protecting groups. The two defined CSPs obtained, when compared with the CSP produced from native randomly linked vancomycin, showed lower retention and enantioselectivity, also if they still separated the same compounds. Thus, no advantages could be found to choose these phases as an alternative to the native vancomycin CSP. 

Berthod, A. et al., Derivatized vancomycin stationary phases for LC chiral separations, Talanta, 43, 1767, 1996. 

Ghassempour, A. et al., Crystalline degradation products of vancomycin as a new chiral stationary phase for liquid chromatography, Chromatographia, 61, 151, 2005. 

Donnecke, J. et ah. Evaluation of a vancomycin chiral stationary phase in packed capillary supercritical fluid chromatography, J. Microcol. Sep., 11, 521, 1999. 

Svensson, L.A. et ah. Vancomycin-based chiral stationary phases for micro-column liquid chromatography. Chirality, 11, 121, 1999. 

Wikstrom, H. et ah. Immobilisation and evaluation of a vancomycin chiral stationary phase for capillary electrochromatography, J. Chromatogr. A, 869, 395, 2000. 

Desiderio, C., Aturki, Z., and Eanali, S., Use of vancomycin silica stationary phase in packed capillary electrochromatography I. Enantiomer separation of basic compounds. Electrophoresis, 22, 535, 2001. 

Kang, W. et ah. Analysis of benidipine enantiomers in human plasma by liquid chromatography—mass spectrometry using a macrocyclic antibiotic (vancomycin) chiral stationary phase column, J. Chromatogr. B, 814, 75, 2005. 

Pihlainen, K. and Kostiainen, R., Effect of the eluent on enantiomer separation of controlled drugs by liquid chromatography-ultraviolet absorbance detection-electrospray ionisation tandem mass spectrometry using vancomycin and native fi-cyclodextrin chiral stationary phases, J. Chromatogr. A, 1033, 91, 2004. 

Bosakova, Z., Cufinovd, E., and Tes ovd, E., Comparison of vancomycin-based stationary phases with different chiral selector coverage for enantioselective separation of selected drugs in high-performance liquid chromatography, J. Chromatogr. A, 1088, 94, 2005. 

Lehotay, J. et al.. Chiral separation of enantiomers of amino acid derivatives by HPLC on vancomycin and teicoplanin chiral stationary phases, Pharmazie, 53, 863, 1998. 

Sun, Q. and Olesik, S.V., Chiral separation by simultaneous use of vancomycin as stationary phase chiral selector and chiral mobile phase additive, J. Chromatogr. B, 745, 159, 2000. 

Aboul-Enein, H.Y. and Serignese, V., Enantiomeric separation of several cyclic imides on a macrocyclic antibiotic (vancomycin) chiral stationary phase under normal and reversed phase conditions, Chirality, 10, 358, 1998. 

Bosikova, Z., Klouhkova, 1., and Tesafova, E., Study of the stability of promethazine enantiomers by liquid chromatography using a vancomycin-bonded chiral stationary phase, J. Chromatogr. B, 770, 63, 2002. 

Lehotay, J. et al.. Separation of enantiomers of some 1,4-piperazine derivatives of aryloxy-aminopropanols on a vancomycin chiral stationary phase, Pharmazie, 54, 743, 1999. 

Tesafova, E., Zaruba, K., and Flieger, M., Enantioseparation of semisynthetic ergot alkaloids on vancomycin and teicoplanin stationary phases, J. Chromatogr. A, 844, 137, 1999. 

Hefnawy, M.M. and Aboul-Enein, H.Y., A validated LC method for the determination of vesamicol enantiomers in human plasma using vancomycin chiral stationary phase and sohd phase extraction, J. Pharm. Biomed. Anal, 35, 535, 2004. 

Armstrong et al. ° first introduced chiral stationary phases based on macrocyclic antibiotics. Vancomycin, ristocetin A, teicoplanin, avoparcin, rifamycin B and thiostrepton are used as chiral selectors. They posses a broad enantiorecognition range, similar to protein based CSPs. However, CSPs based on macrocyclic antibiotics show higher stability and capacities.Underivatized amino acids, N-derivatized amino-acids, acidic compounds, neutrals, amides, esters and amines can be separated.The first four of the above-mentioned chiral selectors appear to have the largest enantiorecognition range.The selectors can also be derivatized to obtain different enantioselectivities. 

Temperature is also an important parameter for controlling the resolution of enantiomers in HPLC. The enthalpy and entropy control of chiral resolution on antibiotic CSPs is similar to the case of polysaccharide-based CSPs (Chapter 2). Armstrong et al. [1] have studied the effect of temperature on the resolution behavior of proglumide, 5-methyl-5-phenylhydantoin and A-carbamyl-D-pheny-lalanine on the vancomycin column. The experiments were carried out from 0°C to 45°C. These results are given in Table 6 for three chiral compounds. It has been observed that the values of k, a, and Rs for the three studied molecules have decreased with the increase in temperature, indicating the enhancement of chiral resolution at low temperature. In another work, the same workers [22] have also studied the effect of temperature on the resolution of certain amino acid derivatives on the teicoplanin chiral stationary phase. They further observed poor resolution at ambient temperature, whereas the resolution increased at low... 

Macrocyclic antibiotics such as teicoplanin and vancomycin have been used in chiral stationary phases separations of amino acids, drugs, and other species using HPLC and other separations methods. These applications have been reviewed in a number of recent sources, including a 2004 monograph on chiral separations. [97, 101-107]... 

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