Chiral resolution of melatoninergic ligands by EKC using highly sulfated CDs

Abstract

EKC methods for the enantiomeric resolutions of melatoninergic ligands were developed using anionic CDs (highly S-alpha-CD, highly S-beta-CD, and highly S-gamma-CD) as chiral selectors at acidic pH 2.5. The optimization of the various operational parameters (nature and concentration of the CD, phosphate buffer concentration, addition of organic modifiers in the BGE, and temperature) allows baseline enantioresolutions (superior to 2) in short analysis times (inferior to 7 min) for all studied analytes. Some analytical characteristics of the optimal method were then studied for each analyte: repeatability, linearity, and LOD and LOQ. Lastly, determination of the apparent binding constants for the 18 complexes formed between the six analytes and the three CDs led us to rationalize the complexation mechanisms.

Dual CD system in capillary electrophoresis for direct separation of the four stereoisomers of agonist and antagonist melatoninergic ligands

“…It is of particular importance in the pharmaceutical industry to develop quality control methods to assess the optical purity of these compounds. As a continuation of our work on the enantioseparation of racemates with potential biological activity 8, 9, here we examined the direct separation of the four stereoisomers ( cis and trans forms synthesised as described in 2, 3) of compounds 1–4, and the two enantiomers ( cis form synthesised as described in 5, 6) of compounds 5 and 6, by CE. This technique allows direct, single‐step analyses of aqueous biological media in contrast to chromatography that often requires preliminary sample preparation.…”

Characterizing the interaction between enantiomers of eight psychoactive drugs and highly sulfated‐β‐cyclodextrin by counter‐current capillary electrophoresis

“…Although we have not found literature binding data for the analytes studied in this work, some reported values are available for other basic compounds (Vaccher et al ., ; Rudaz et al ., ; Foulon et al ., ; Lipka et al ., ; Danel et al ., ). The K ′ values of enantiomer‐HS‐ β ‐CD in Table are similar to or higher than those in the literature, confirming the extraordinarily good enantioseparation capabilities of this commercial mixture cyclodextrin.…”

“…Highly sulfated cyclodextrins (HS-CDs) are a relatively recent family of CDs with good enantiomeric separation ability of numerous acidic, neutral and basic analytes (Perrin et al, 2001;Matthijs et al, 2002;Verleysen et al, 1999;Chen et al, 2001;Vescina et al, 2002;Vaccher et al, 2005;Rudaz et al, 2004;Foulon et al, 2002;Lipka et al, 2007;Danel et al, 2005). These CDs have a high density of negative charge in a broad pH range, so their electrophoretic mobility makes them adequate for counter-current separations.…”

Synthesis of 2,3 and 4,5-Dihydro-hydroxy-isoxazoles and Isoxazoles Under Different pH Conditions

“…CE confirmed results obtained from HPLC and was run with anionic cyclodextrins (highly sulfated--CD) as driving selectors. Cyclodextrins were chosen because of their remarkable ability to form inclusion complexes with a wide variety of molecules [20,21]. Analysis was carried out with a 25 mM phosphate buffer, pH 2.5.…”