Separation of optical isomers of scopolamine, cocaine, homatropine, and atropine.

Different drug stereoisomers can have different physiological and therapeutic effects. Difficulties in separating optical isomers often make it impractical to market stereochemically pure products or to monitor isomeric contamination. This is not thought to be a problem with drugs isolated from biological sources (the alkaloids, for example). However, small amounts of isomeric impurities also exist in many biological systems. More importantly the isolation and purification process can cause partial or complete racimization in some cases. Great care must be taken in the handling of some drugs and an efficient, sensitive means to monitor racimization is important. Liquid chromatographic separation on a chiral beta-cyclodextrin bonded phase can be an effective technique in many cases. Its use in separating optical isomers of dl-scopolamine, dl-hyoscyamine, dl-homatropine, and dl-cocaine is discussed.