Enantioselective determination by capillary electrophoresis with cyclodextrins as chiral selectors.

Enantioseparations in capillary electromigration techniques: recent developments and future trends

Enantioseparations by using capillary electrophoretic techniques. The story of 20 and a few more years.

Chiral separation by capillary electromigration techniques.

This review gives a survey of different chiral separation principles and their use in high-performance liquid chromatography (HPLC), gas chromatography (GC), supercritical fluid chromatography (SFC), thin-layer chromatography (TLC), capillary electrophoresis (CE) and capillary electrochromatography (CEC) highlighting new developments and innovative techniques. The mechanisms of the different separation principles are briefly discussed and some selected applications are shown.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/bdd.279

Chiral separation by chromatographic and electromigration techniques. A Review

Impact of methanol and acetonitrile on separations based on π–π interactions with a reversed-phase phenyl column

Achievement of enantioselectivity of non-polar primary amines by a non-chiral crown ether

Enhancement of chiral recognition by formation of a sandwiched complex in capillary electrophoresis.

Ritalin, [(+)-threo]methylphenidate hydrochloride, is a chiral drug substance with two chiral centers. The drug substance may contain three pairs of enantiomers, [(+)-threo], [(-)-threo], [(+)-erythro] and [(-)-erythro] isomers, and its degradation products, threoritalinic acid racemate. Determination of the optical purity of ritalin drug substance and the amount of its by-product isomers is a critical step in the single-isomer drug development. In order to efficiently recognize the three pairs of enantiomers by one method, capillary electrophoresis (CE) was employed for the separation. The three pairs of enantiomers in CE showed different enantioselectivities with eight different types of CDs. Only 2,6-di-o-methyl-beta-cyclodextrin (DM-beta-CD) and carboxymethyl-beta-cyclodextrin (CM-beta-CD) showed enantioselectivity to all these pairs of enantiomers. With respect to separation resolution and efficiency, DM-beta-CD was chosen as the chiral selector. For optimization of the separation conditions, the concentration of DM-beta-CD, pH of the buffer solution, and temperature of the capillary were further studied.

Separation of ritalin racemate and its by-product racemates by capillary electrophoresis.

A method to form a UV-active derivative of 1-methyl-4-amino-piperazine (AMP) was developed. The method was based on the reaction of AMP with benzaldehyde, forming a stable derivative, which was UV-active. The method was used to analyze samples of an active pharmaceutical ingredient (API) for trace amounts of AMP. The derivatization approach allowed detection of AMP at low levels, using readily available HPLC-UV instrumentation. The method was validated in the range of about 30 to 190 ppm (on a mass to mass basis relative to API). It was shown through spiked recovery tests that the derivatization reaction occurred smoothly without interference from the API. The results suggest that other organohydrazine compounds may be amenable to the same derivatization technique.

Steven D. Fazio

Papers

Impact of methanol and acetonitrile on separations based on π–π interactions with a reversed-phase phenyl column

Achievement of enantioselectivity of non-polar primary amines by a non-chiral crown ether

Enhancement of chiral recognition by formation of a sandwiched complex in capillary electrophoresis.

Separation of ritalin racemate and its by-product racemates by capillary electrophoresis.

Analytical method for 1-methyl-4-amino-piperazine in an active pharmaceutical ingredient using chemical derivatization and hplc-uv