Vancomycin chirobiotic 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. 

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

The teicoplanin CSP (Chirobiotic T) exhibits enantioselectivity for underivatized and Mderivatized (FMOC or Z) amino acids, hydroxy carboxylic acids and other chiral acids including chiral phenols, small peptides, neutral aromatic analytes and cyclic aromatic and aliphatic amines [285] (see also Table 9.11). Selection of the mobile phase mcxle (reversed-phase, normal-phase, or polar-organic phase mode) follows the same criteria as described for vancomycin CSP. 

The Chirobiotic series of colrrmns (T based on teicoplarrin and V on vancomycin as immobilized chiral selector) can be used with polar-organic mobile phase of over 90% methanol and a small amount of aqueous acid or salt solution. 

The group of Bakhtiar [57-59] described the chiral bioanalysis of MPH in various matrices, utilizing a number of sample pretreatment strategies, separation on a Chirobiotic V columns, and the use of positive-ion APCI-MS in SRM mode. The chiral selectivity of the Chirobiotic V column is based on the use of the macrocyclic glycopeptide antibiotic vancomycin. The column can be used in both aqueous and organic mobile phase. 

The chromatographic system chosen to examine was the chiral stationary phase Chirobiotic V (as already described, this is a macrocyclic glycopeptide called Vancomycin bonded to silica gel particles 5 pm in diameter) which was used in the normal phase mode (solute retention controlled largely by polar interactions), employing mixtures of hexane and ethanol as the mobile phase. 

Figure 3 Separation of citalopram and its demethylated metabolites in a human plasma extract on a vancomycin phase. Column 4.6 mm x 15 cm stationary phase Chirobiotic V, 5 pm mobile phase methanol-acetic acid-triethylamine (99.9 0.055 0.06, v/v/v), 1 ml min detector fluorescence 240/296 nm. The structure of the drug is shown it is used as the racemate. Peaks 1, alprenolol (internal standard) 2, R- - )-didesmethylcitalopram 3, R-( - )-desmethylcitalopram 4, R- - )-citalopram 5, S-( + )-citalopram 6, S-(+ )-desmethylcitalopram. S- + )-didesmethylcitalopram is not present. (Reproduced with permission from Kosel M, Eap CB, Amey M, and Baumann P (1998) Analysis of the enantiomers of citalopram. Journal of Chromatography B 719 234.)...

Since first demonstration in 1994 of the potential use of macrocyclic antibiotics as chiral selectors in analysis, glycopeptide antibiotics have been successfully applied for enantiomer separations by liquid chromatography, as recognition components of chiral stationary phases, and by capillary electrophoresis (CE) as soluble chiral selec-tors. Four chiral stationary phases for chromatography with the selectors vancomycin, ristocetin, teicoplanin, and the teicoplanin aglycone are commercialized under the trade name Chirobiotic by Astec and Supelco. Various aspects of analytical applications of glycopeptide antibiotics have been extensively covered in the recent reviews cited above. As an example. Table 2 shows some representative results for CE enantioseparations with vancomycin, ristocetin A, and teicoplanin, which were taken from Ref. 39. 

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