6-O-(2-hydroxybutyl)-β-CD as a chiral selector for nonaqueous capillary electrophoretic separation of chiral drugs

Abstract

6-O-(2-hydroxybutyl)-β-CD, as a new β-cyclodextrin (β-CD) derivative, was successfully synthesized. It was used as a chiral selector to separate six chiral drugs, including propranolol, anisodamine, promethazine, ketoconazole, benzhexol, and fenfluramine in nonaqueous capillary electrophoresis (NACE). The effects of the organic solvent, the electrolytes, the concentrations of cyclodextrin derivatives, and the pH of the buffer on the chiral resolution (Rs) were investigated. The baseline separation of enantiomers, including propranolol (Rs = 2.26), anisodamine (Rs = 2.31), promethazine (Rs = 2.42), ketoconazole (Rs = 2.56), benzhexol (Rs = 3.38), and fenfluramine (Rs = 3.04), could be achieved using a buffer of 100 mmol · Lt−1 citric acid and 50 mmol · Lt−1 Tris (hydroxymethyl) aminomethane (Tris) at pH 4.6 containing 100 mmol · Lt−1 6-O-(2-hydroxybutyl)-β-CD in formamide (FA).