Enantioseparation of Three β-Agonists Using Di-n-butyl d-Tartrate-Boric Acid Complex as Chiral Selector by Means of MEEKC

Abstract

In this study, a self-prepared complex chiral selector, di-n-butyl D-tartrate-boric acid complex, by the reaction of di-n-butyl D-tartrate with boric acid in a running buffer was used as a chiral selector for the enantioseparation of three b-agonists including clenbuterol, cycloclenbuterol and tulobuterol by means of microemulsion electrokinetic chromatography (MEEKC). Three b-agonists were successfully enantioseparated using the chiral system, indicating that the di-n-butyl D-tartrate-boric acid complex was a useful chiral selector. The effects of di-nbutyl D-tartrate and sodium tetraborate concentration, surfactant concentration, cosurfactant, phosphate, buffer pH and composition, as well as applied voltage were extensively investigated to achieve a good enantioseparation. The di-n-butyl D-tartrate and sodium tetraborate concentration in the running buffer had great influence on the chiral resolution (R s ). Three b-agonists which could not be separated with only di-n-butyl D-tartrate, obtained good chiral separation using the complex chiral selector; among them, two pairs including clenbuterol and cycloclenbuterol could be baseline resolved in 7 min under optimized experimental conditions of 0.8% (w/v) di-n-butyl D-tartrate, 40 mM sodium tetraborate, 3.0% (w/v) Tween-20 and 60 mM sodium dihydrogen phosphate with 25 kV as running voltage. The results indicated that the method could be used for the enantioseparation of three b-agonists.

Twenty‐one years of microemulsion electrokinetic chromatography (1991–2012): A powerful analytical tool

“…In other studies, the transparent and stable microemulsions could be prepared without co‐surfactant . Nozal et al.…”

“…The CD‐MEEKC methods were also employed to separate enantiomer, such as dopa, methyldopa, phenylalanine, tyrosine , esbiothrin , oxybutynin , and tropa alkaloids . Interestingly, β‐blockers and structural related substances were separated by the complex chiral selector , and relatively good chiral resolution performance was obtained.…”

Recent developments in chiral analysis of β‐blocker drugs by capillary electromigration techniques

“…The increase of triethylamine concentration also decreases EOF, which may be advantageous for chiral separation because a decrease of EOF should increase the difference of effective mobility of the enantiomers. Meanwhile, the author prepared di‐ n ‐butyl d ‐tartrate‐boric acid complex as a chiral selector for the enantioseparation of three β‐agonists including clenbuterol, cycloclenbuterol, and tulobuterol in chiral MEEKC . Three β‐agonists were successfully enantioseparated using the chiral system, indicating that the di‐ n ‐butyl d ‐tartrate–boric acid complex was a useful chiral selector.…”

Chiral separation of propranolol by electrokinetic chromatography using nanodiamonds and human serum albumin as a pseudo‐stationary phase in river water

“…As the S-isomer of propranolol is 100 times more pharmacologically active than the R-isomer, 2 a quantitative and enantioselective study is essential in order to develop racemic drugs. 1,[3][4][5] Due to the widespread use of β-blockers, R-enantiomers are commonly found in sewage effluents and surface waters because of their incomplete metabolization and their excretion through urine. 6 Propranolol exhibits a high degree of bioaccumulation, which is considered as a harmful compound to aquatic organisms.…”

“…It is important to consider the specific case of propranolol, where the S (−) enantiomer is having pharmacologic activity and the R (+) isomer is generally showing toxicological effects. As the S‐ isomer of propranolol is 100 times more pharmacologically active than the R‐ isomer, 2 a quantitative and enantioselective study is essential in order to develop racemic drugs 1,3–5 . Due to the widespread use of β‐blockers, R ‐enantiomers are commonly found in sewage effluents and surface waters because of their incomplete metabolization and their excretion through urine 6 .…”