Separation of mandelic acid and its derivatives with new immobilized cellulose chiral stationary phase

Development and validation of a novel chiral chromatographic method for separation of lenalidomide enantiomers in human plasma

Lenalidomide (LND) is an analogue of thalidomide that is second generation immunomodulatory drugs (IMiDs). LND contains asymmetric carbon atom and exist R and S enantiomer. S (-) form of enantiomer are considered to be more potent and biologically active in tumor cell. It is available in racemic form for clinical use. The study aims to develop and validate enantiomer separation of LND in human plasma. The chromatographic enantiomeric separation was achieved on a Daicel-CSP, Chiralpack IA 4.6 × 250 mm_5 μm. The mobile phase was constituted in combination of methanol:glacial acetic acid at a concentration of 499.50 ml: 50 μl. UV wavelength detection was 220 nm. The RSD% for all validation parameters was found to be within the acceptable limit. The chiral chromatographic (chiral stationary phase-high-performance liquid chromatography [CSP-HPLC]) method developed and validated for the quantitative estimation of LND enantiomers S (-) and R (+) in human plasma sample is accurate, precise, robust, stable and selective.

Chiroptical characterization tools for asymmetric small molecules - experimental and computational approaches for electronic circular dichroism (ECD) and anisotropy spectroscopy

Synchrotron radiation electronic circular dichroism (SRECD) and anisotropy spectroscopy for both enantiomers of a group of small non-planar chiral molecules are reported here. The experimental SRECD spectra are compared to computational ECD spectra generated using time-dependent density functional theory and a thermal averaging over relevant molecular configurations. The combination of these experimental and computational characterization methodologies for such molecules enables the prediction and understanding of the spectral behavior of other small molecules, in addition to chiroptically characterizing members of the mandelic acid family substructure. Enantiomeric purity of samples can be evaluated in comparison with these spectra and the extent of photolytic enantioinduction can also be predicted using these experimental/calculated SRECD and anisotropy spectra.

Experimental and computational electronic circular dichroism spectra are used in conjunction with anisotropy spectra to chiroptically characterize mandelic acid and its derivatives into the vacuum UV.

Rational design and tailoring of imprinted polymeric enantioselective sensor layered on multiwalled carbon nanotubes for the chiral recognition of d-mandelic acid

Attempts have been made to investigate the feasibility of fabricating an enantiomeric sensor for the specific detection of d-mandelic acid layered on vinyl-MWCNT using molecular imprinting technology.

Application of Carbon Nanotubes in Chiral and Achiral Separations of Pharmaceuticals, Biologics and Chemicals

Carbon nanotubes (CNTs) possess unique mechanical, physical, electrical and absorbability properties coupled with their nanometer dimensional scale that renders them extremely valuable for applications in many fields including nanotechnology and chromatographic separation. The aim of this review is to provide an updated overview about the applications of CNTs in chiral and achiral separations of pharmaceuticals, biologics and chemicals. Chiral single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) have been directly applied for the enantioseparation of pharmaceuticals and biologicals by using them as stationary or pseudostationary phases in chromatographic separation techniques such as high-performance liquid chromatography (HPLC), capillary electrophoresis (CE) and gas chromatography (GC). Achiral MWCNTs have been used for achiral separations as efficient sorbent objects in solid-phase extraction techniques of biochemicals and drugs. Achiral SWCNTs have been applied in achiral separation of biological samples. Achiral SWCNTs and MWCNTs have been also successfully used to separate achiral mixtures of pharmaceuticals and chemicals. Collectively, functionalized CNTs have been indirectly applied in separation science by enhancing the enantioseparation of different chiral selectors whereas non-functionalized CNTs have shown efficient capabilities for chiral separations by using techniques such as encapsulation or immobilization in polymer monolithic columns.