Enantiomeric separation of acidic drugs by capillary electrophoresis using a combination of charged and uncharged β‐cyclodextrins as chiral selectors

Abstract

SummaryHigh resolution could be achieved for the enantiomers of acidic drugs, namely, sulindac, fenoprofen, ketoprofen, warfarin, and hexobarbital, in a buffer of pH 3 by the simultaneous addition of uncharged and charged b-cyclodextrin derivatives. The interaction of the analytes with the anionic sulfobutyl ether P-cyclodextrin provides the analytes with an adequate electrophoretic mobility whereas the interaction with various neutral P-cyclodextrins generates high enantioselectivity. Five neutral cyclodextrins, the native P-cyclodextrin, as well as methyl-, dimethyl-, trimethyl-and hydroxypropyl-P-cyclodextrin, were tested to enhance the enantioselectivity of the electrophoretic system. High resolution values and the shortest analysis times for the five drugs tested were achieved in a buffer made of 100 mM phosphoric acid adjusted to pH 3 with triethanolamine and containing dimethyl-or trimethyl-0-cyclodextrin in addition to sulfobutyl ether P-cyclodextrin.

Enantiomeric Separations in Capillary Electrophoresis Using 18-Crown-6-tetracarboxylic Acid (18C6H4) as Buffer Additive

“…sulfobutyl ether b-CD [7,8], carboxymethyl b-CD [9], ...) and cyclodextrins imprinted in polymers [10,11] or in coatings [12,13] have been used. Some reports discuss the applicability of dual-cyclodextrin systems, in which charged and uncharged cyclodextrins are mixed [14,15]. Proteins like human serum albumin [16], ovomucoid [17], avidin [18], etc., have been used, but their application range is somewhat limited, on the one hand, because of their high UVabsorbance and, on the other hand, because of adsorption on the capillary wall.…”

Separation of Regioisomers of Substituted Bromoindoles of Pharmaceutical Interest by RP-HPLC and Capillary Electrophoresis Based on Interaction with Sulfobutyl Ether-β-cyclodextrin

“…The sulfonic groups of SBE-b-CD are dissociated over a very large pH range and even at pH 2 they are still present in an anionic form [3,4]. SBE-b-CD therefore has an electrophoretic mobility in the direction of the anode.…”

Stereoselective determination of S-naproxen in tablets by capillary electrophoresis

“…A series of chiral acidic compounds containing carboxy groups, such as NSAIDs, were also enantioseparated by simultaneous addition of anionic and uncharged i-CD derivatives to a phosphoric acid/triethanolamine pH 3 buffer [11,12].…”

“…In previous papers, we demonstrated the suitability of this kind of BGE for the enantiomeric separation of basic, acidic and even neutral drugs [6,11,12,19].…”