Enantiomeric Separation and Determination of the Enantiomeric Impurity of Armodafinil by Capillary Electrophoresis with Sulfobutyl Ether-[beta]-cyclodextrin as Chiral Selector

• Published in: Molecules (Basel, Switzerland) Vol. 17; no. 1; p. 303
• Main Authors: Wang, Wei, Xiang, Suyun, Zhou, Xiaojuan, Ji, Yibing, Xiang, Bingren
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.01.2012
• Subjects: Capillary electrophoresis; Electrolytes; Pharmaceutical industry; Quality control; Shift work; Sleep apnea; Sleep disorders; Viscosity; China
• ISSN: 1420-3049
• DOI: 10.3390/molecules17010303

A selective capillary electrophoresis method using sulfobutyl ether-β-cyclodextrin as a chiral selector was developed and validated for the determination of the enantiomeric impurity of (R)-modafinil, i.e., armodafinil. Several parameters were optimized for a satisfactory enantioresolution, including the type and concentration of chiral selector and organic modifier, pH of background electrolyte (BGE), capillary temperature. The finally adopted condition was: 20 mmol/L phosphate buffer at pH 7.5, containing 20 mmol/L sulfobutyl ether-β-cyclodextrin and 20% methanol, at temperature of 25 °C. A good resolution of 3.3 for the two enantiomers of modafinil was achieved by applying the optimal conditions. The limit of detection (LOD) and limit of quantification (LOQ) of (S)-modafinil were 1.25 μg/mL and 2.50 μg/mL, respectively. The established method was also proven to display good selectivity, repeatability, linearity and accuracy. Finally, the method was used to investigate the enantiomeric purity of armodafinil in bulk samples.