| Student Research at Millsaps |
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The
Laboratory of Dr. Timothy J. Ward
Introduction
Many
people may not be aware that many over the counter (OTC) as well
as prescription drugs are actually marketed as two drugs called
isomers. One of the most common drugs that exists as two isomers
is ibuprofen, sold under the trade name advil and motrin. One isomer
of this drug has a beneficial effect, and the other isomer is passed
through the body. The drug thalidomide was marketed as a racemic
mixture in the 1960s. One isomer of the drug has therapeutic uses,
and the other isomers of the drug caused many children to have birth
defects.
 The atoms that are the components of molecules may have different orientations in space, and stereochemistry is the study of these different configurations. The different configurations are called stereochemical isomers. A molecule that cannot be superimposed on its mirror image is called an enantiomer, and a molecule that has two or more enantiomeric forms is referred to as being chiral. A mixture containing equal portions of the different enantiomers of a molecule is called a racemic mixture. Many drugs, pesticides, and other chemicals are sold as racemic mixtures, and the Food and Drug Administration is placing more importance on the ability to separate the constituent enantiomers of these racemic mixtures. The separation of the racemic mixtures will allow the characterizerization of the enantiomers and the determination of their physiological effects. This is extremely significant due to the fact that some enantiomers composing drugs may have no effect, and some enantiomers may actually be harmful. Our Research The separation of racemic mixtures into their prospective enantiomers can be quite difficult, however, due to the fact that the enantiomers have very similar physical and chemical properties. Our research group has done research using capillary electrophoresis (CE) for chiral separations. Our laboratory is equipped with a BioFocus 3000 CE system that we will use in our research. The BioFocus 3000 CE system is fully automated and is computer-controlled. Our research laboratory is also equipped with two Isco CE systems and a Shimadzu High Performance Liquid Chromatography (HPLC) system. Macrocyclic antibiotics have proven to be useful chiral selectors that aid in chiral separations, and these molecules are used in the research carried out in our laboratory. Our research group also does investigations into the coating of the CE columns. The coating of the capillary columns is particularly important because it helps to suppress electroosmotic flow in the capillary columns making the chiral separations much more efficient. An illustration of the chiral separation technique we use is shown below (click for a larger view):  |
