Evaluation of sulfated maltodextrin as a novel anionic chiral selector for the enantioseparation of basic chiral drugs by capillary electrophoresis

Abstract

Introducing a new class of chiral selectors is an interesting work and this issue is still one of the hot topics in separation science and chirality. In this study, for the first time, sulfated maltodextrin (MD) was synthesized as a new anionic chiral selector and then it was successfully applied for the enantioseparation of five basic drugs (amlodipine, hydroxyzine, fluoxetine, tolterodine, and tramadol) as model chiral compounds using CE. This chiral selector has two recognition sites: a helical structure and a sulfated group which contribute to three corresponding driving forces; inclusion complexation, electrostatic interaction, and hydrogen binding. Under the optimized condition (buffer solution: 50 mM phosphate (pH 3.0) and 2% w/v sulfated MD; applied voltage: 18 kV; temperature: 20°C), baseline enantioseparation was observed for all mentioned chiral drugs. When instead of sulfated MD neutral MD was used under the same condition, no enantioseparation was observed which means the resolution power of sulfated MD is higher than neutral MD due to the electrostatic interaction between sulfated groups and protonated chiral drugs. Also, the countercurrent mobility of negatively charged MD (sulfated MD) allows more interactions between the chiral selector and chiral drugs and this in turn results in a successful resolution for the enantiomers. Furthermore, a higher concentration of neutral MD (approximately five times) is necessary to achieve the equivalent resolution compared with the negatively charged MD.

Preparation and chromatographic performance of a multifunctional immobilized chiral stationary phase based on dialdehyde microcrystalline cellulose derivatives

“…The importance of enantioseparation is increasing because of its wide range of applications in pharmaceuticals, pesticides, food additives, and many other industries. [1][2][3][4] In enantiomeric separation, high-performance liquid chromatography (HPLC) is one of the most effective methods of chiral separation with high resolution efficiency and universal applicability. 5,6 Thereinto, chiral stationary phase is the core and key part of chiral separation in HPLC.…”

Capillary electrophoresis in the enantioseparation of modern antidepressants: An overview

“…When a neutral MD was used under the same analytical conditions, no enantioseparation was observed, which demonstrates the higher-resolution power of sulfated MD owing to the electrostatic interaction between its sulfated groups and protonated chiral drugs (Tabani, Mahyari, Sahragard, Fakhari, & Shaabani, 2015). Under acidic conditions, FLX is positively charged and consequently migrates toward the cathode, while sulfated MD is negatively charged and migrates toward the anode.…”

Analytical methodologies for the stereoselective determination of fluoxetine: An overview

“…FLX was used also as model chiral molecule for the evaluation of the enantioseparative capacity of some new chiral selectors for CE, like N‐ (3‐sulfo,3‐carboxy)‐propionylchitosan (Budanova, Shapovalova, Lopatin, Varlamov, & Shpigun, ), sulfated maltodextrin (Tabani, Mahyari, Sahragard, Fakhari, & Shaabani, ) or a newly synthesized CD like octakis(2,3‐dimethyl‐6‐O‐sulfo)‐ γ ‐CD in high‐pH aqueous background electrolyte (Bubsy, Maldonado, & Vigh, ).…”