Chiral separation and quantitative analysis of citalopram by modified capillary electrophoresis

Stereoselective enrichment and determination of citalopram enantiomers by cation-selective exhaustive injection and sweeping coupled with cyclodextrin modified electrokinetic chromatography

An highly sensitive, rapid and enantioselective method was developed for the enantioseparation and determination of citalopram enantiomers by cation selective exhaustive injection-sweeping-cyclodextrin modified electrokinetic chromatography (CSEI-sweeping-CDEKC). The optimized conditions were: 50 mM pH 3.0 phosphate solution with 25 mg·mL^-1 S-β-CD used as background buffer, 50 mbar 300 s hydrodynamical injection of 150 mM pH 3.0 NaH₂PO₄ buffer followed with 5 s water plug, 10 kV 600 s electrokinetic sample injection, -20 kV CDEKC run. Under the optimized conditions, the resolution was Rs=8.04, the enrichment factor as up to 2163 folds, the LOD values were: 3.6 ng·mL^-1 for R-citalopram, 4.1 ng·mL^-1 for S-citalopram, and 3 ng·mL^-1 for both enantiomers in plasma samples. This new method showed good precision, repeatability and stability, which had been successfully applied to the impurity inspection of escitalopram oxalate and the stereoselective pharmacokinetic study of citalopram enantiomers.

(1R,3S)-3-(1H-Benzo[d]imidazol-2-yl)-1,2,2-tri-methyl-cyclo-pentane-1-carb-oxy-lic acid as a new anti-diabetic active pharmaceutical ingredient

The chiral title compound, C16H20N2O2, which can be used for producing active pharmaceutical ingredients for treatment of type 2 pancreatic diabetes and other pathologies dependent on insulin resistance, was prepared from (1R,3S)-camphoric acid and o-phenyl-enedi-amine. It crystallized from an ethanol solution in the chiral monoclinic P21 space group. The five-membered ring adopts a twisted conformation with the methyl-substituted C atoms displaced by -0.273 (5) and 0.407 (5) Å from the mean plane through the other three atoms. In the crystal, mol-ecules are linked by O-H⋯N hydrogen bonds, forming chains along the a-axis direction. Hirshfeld surface analysis and two-dimensional fingerprint plots were used to analyze the inter-molecular contacts present in the crystal.

Dispersive liquid-liquid microextraction combined with acetonitrile stacking through capillary electrophoresis for the determination of three selective serotonin reuptake inhibitor drugs in body fluids

Dispersive liquid-liquid microextraction was combined with acetonitrile stacking in capillary electrophoresis for the identification of three selective serotonin reuptake inhibitors (citalopram, fluoxetine, and fluvoxamine) in human fluids such as urine and plasma. Parameters that affect the extraction and stacking efficiency, such as the type and volume of the extraction and disperser solvent, extraction time, salt addition for dispersive liquid-liquid microextraction, and sample matrices, pH, and concentration of the separation buffer for stacking, were investigated and optimized. Under optimum conditions, the enrichment factors were in the range of 1195-1441. Limits of detection ranged from 1.4 to 1.7 nM for the target analytes. Calibration graphs displayed satisfied linearity with R² greater than or equal to 0.9978, and relative standard deviations of the peak area analysis were in the range of 2.9-5.0% (n = 3). The recoveries of all tricyclic antidepressant drugs from urine and plasma were in the range of 77-117 and 79-106%, respectively. The findings of this study show that dispersive liquid-liquid microextraction acetonitrile-stacking capillary electrophoresis is a rapid and convenient method for identifying tricyclic antidepressant drugs in urine and plasma.