On the other hand, many pyrethroids are marketed as racemic mixtures
, which have in equal enantiomeric proportions.
In this study, chiral separation of 36 racemic mixtures
of synthetic cathinone derivatives was carried out: fourteen of them were selected in the spiked mixtures, and each enantiomer was quantitated in urine and plasma as shown in the example of nor-mephedrone in Figure 1.
453, 453-54 (2009) (describing how the FDAAA allowed enantiomers of previously approved racemic mixtures
to get five years of market exclusivity).
(114) An equal mixture of enantiomers is termed a racemic mixture
Chiral columns, which are used with SFC and HPLC, are packed with media that separates enantiomers from racemic mixtures
, thus yielding a chirally pure substance.
Used to resolve chiral compounds from racemic mixtures
into pure enantiomers, SMB capability is one of the fastest methods to obtain enantiomerically pure drugs, increasingly important as the demand for single-enantiomer drugs continues to grow.
All other currently available albuterol bronchodilators are 50/50 racemic mixtures
, containing both R- and S-isomers.
Most endogenous compounds produced in the body are "pure" single isomers, while most synthetic drugs are racemic mixtures
. "We have known for a long time that, physiologically, the isomers behave very differently," explained Dr.
As temperature increases, ordinary chemical reactions tend to generate equal proportions of the two isomers, producing so-called racemic mixtures
Separation of neutral and ionic compounds may be achieved on the basis of differential solute distribution and the differential migration of the micellar phase.(6,7) The further addition of bile salts to the electrolyte has been successful for the separation of very lipophilic compounds.(8) The resolving of racemic mixtures
has also been achieved through the incorporation into the electrolyte of chiral additives, which serve to create mobility differences through diastereomeric interaction with analyte molecules.(9,10,11)
"It could be used to quantify ratios of enantiomers in racemic mixtures
. The wavelength shifts of polar molecular sections caused by optically active solvents may be used to measure this ratio.
The latter are racemic mixtures
, whereas ropivacaine is the pure (S)-enantiomer.