Ethambutol
(S,S)-(+)-Ethambutol is powerful and selective antitubercular drug. It is a classical example of an old drug that was introduced for clinical use in its chirally pure form. Chirality and biological activity Ethambutol contains two constitutionally symmetrical stereogenic centers in its structure and exists in three stereoisomeric forms. An enantiomeric pair (S,S)- and (R,R)-ethambutol, along with the achiral stereoisomer called meso-form. The activity of the drug resides in the (S,S)-(+)-enantiomer which is 500 and 12 fold more …