Sulfa drugsIn 1951, a patent for improved sulfonamide drugs was issued to James W. Clapp and Richard O. Roblin, (U.S. No. 2,554,816). Sulfa drugs are members of a group of synthetic antibacterial drugs containing the sulfanilamide molecular structure. Sulfonamides (first observed in 1932) were the first chemical substances that were systematically used to cure and prevent bacterial infections in humans. Of the 5,000 sulfa drugs prepared and tested, fewer than 20 continue to have therapeutic value because resistant strains of bacteria have developed. More potent antibacterial drugs have largely replaced the sulfa drugs. They remain useful in the treatment of urinary tract infection.[Image: The general formula of the patented drugs is a 5-membered heterocyclic sulfonamide having at least 3-hetero atoms. X is carbon or nitrogen which may have substituents such as hydroxyl, amino, acylamino or sulfonanide radicals; R and R' can be hydrogen, alkyl, alkaryl or aryl radicals; Y is sulfur or nitrogen (which in the case of nitrogen may have substituents such as an aryl or alkyl radical. Also X, Y may be part of a fused ring system in which the 5-membered ring shown forms a ring fused with a 6-membered heterocyclic ring such a pyridine.] |
