title: Design of experiments for enantiomeric separation in supercritical fluid chromatography.
abstract: A new chiral melatoninergic ligand, potentially successor of Valdoxan(®), presenting an improved pharmacological profile with regard to agomelatine, was chosen as a probe for a supercritical fluid chromatographic separation carried-out on an amylose tris[(S)-1-α-methylbenzylcarbamate] based stationary phase. The goal of this work was to optimize simultaneously three factors identified to have a significant influence to obtain the best resolution in the shortest analysis time (i.e., retention time of the second eluting enantiomer) for this chiral compound. For this purpose a central circumscribed composite (CCC) design was developed with three factors: the flow-rate, the pressure outlet and the percentage of ethanol to optimize of two responses: shortest analysis time and best resolution. The optimal conditions obtained via the optimizer mode of the software (using the Nelder-Mead method) i.e., CO2/EtOH 86:14 (v:v), 104bar, 3.2mLmin(-1) at 35°C lead to a resolution of 3.27 in less than 6min. These conditions were transposed to a preparative scale where a concentrated methanolic solution of 40mM was injected with a sample loop of 100μL. This step allowed to separate an amount of around 65mg of racemic melatonin ligand in only 3h with impressive yields (97%) and enantiomeric excess (99.5%).
authors.affiliation: Univ Lille, Inserm-UMR-S 1172- JPArc-Centre de Recherche Jean-Pierre AUBERT Neurosciences et Cancer, F-59000 Lille, France.
authors.forename: Elodie
authors.initials: E
authors.lastname: Landagaray
authors.affiliation: EA GRITA 7365, Univ. Lille, Faculté de Pharmacie de Lille, F-59000 Lille, France.
authors.forename: Claude
authors.initials: C
authors.lastname: Vaccher
authors.affiliation: Univ Lille, Inserm-UMR-S 1172- JPArc-Centre de Recherche Jean-Pierre AUBERT Neurosciences et Cancer, F-59000 Lille, France.
authors.forename: Saïd
authors.initials: S
authors.lastname: Yous
authors.affiliation: Univ Lille, Inserm, U995-LIRIC-Lille Inflammation Research International Center, F-59000 Lille, France. Electronic address: emmanuelle.lipka@univ-lille2.fr.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Lipka
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods / Q000592:standards; D025924:Chromatography, Supercritical Fluid / Q000379:methods* / Q000592:standards; D008550:Melatonin / Q000032:analysis / Q000737:chemistry; D015203:Reproducibility of Results; D012107:Research Design / Q000592:standards; D013237:Stereoisomerism
chemical_list: D008550:Melatonin
keywords: Chiral separation; Experimental design; Melatoninergic ligands; Naphtalens; Optimization; Polysaccharide chiral stationary phase