ASulfonamide (orsulphonamide) is a kind ofdrug. It is a man-madeantibiotic. Their ability to killinfectiousbacteria is their main function, but some types have other medical uses.[1] For example, sulfasalazine, in addition to its use as an antibiotic, is also used in the treatment of inflammatorybowel disease.
Sulfonamides (sometimes calledsulfa drugs orsulpha drugs) contain the sulfonamide chemical group. The best known of the antibiotic sulfonamide drugs is calledSulfanilimide.
Inbacteria, antibacterial sulfonamidesinhibit theenzyme DHPS. The enzyme makesfolic acid, aB vitamin. The microorganism is "starved" of folate and dies.[2]Humans, unlike bacteria, get folate (vitamin B9) through their diet.
Sulfonamide drugs were the first antimicrobial drugs. They paved the way for the antibiotic revolution in medicine. Experiments with the first sulfonamide began in 1932 in the laboratories ofBayer AG, at that time a component of the huge German chemical trustIG Farben. After years of fruitless trial-and-error work on hundreds of compounds, a team led by physician/researcherGerhard Domagk finally found one that worked: a red dye synthesized by Bayer chemistJosef Klarer which had remarkable effects on stopping some bacterial infections in mice.[3] The first official communication about the breakthrough discovery was not published until 1935, more than two years after the drug was patented by Klarer and his research partner Fritz Mietzsch.
Prontosil, as Bayer named the new drug, was the first medicine ever discovered that could effectively treat a range of bacterial infections inside the body. It had a strong protective action against infections caused bystreptococci, and a lesser effect on infections caused by other cocci. However, it had no effect at all in the test tube, exerting its antibacterial action only in live animals. Later, it was discovered that the drug was split into two pieces inside the body, releasing from the inactive dye a smaller, colourless, active compound calledsulfanilamide.[4][5] The discovery dashed the corporation's dreams of enormous profit. The active molecule sulfanilamide (or sulfa) had first been synthesized in 1906 and was widely used in the dye-making industry; its patent had since expired and the drug was available to anyone.[6]
The result was a sulfa craze.[7] As the first and only effective antibiotic available in the years beforepenicillin, sulfa drugs continued to thrive through the early years ofWorld War II.[8] They are credited with saving the lives of tens of thousands of patients, including Franklin Delano Roosevelt, Jr. (son of PresidentFranklin Delano Roosevelt) (in 1936) andWinston Churchill. Sulfa had a central role in preventingwound infections during the war. American soldiers were issued afirst-aid kit containing sulfa pills and powder, and were told to sprinkle the powder on any open wound.
Many thousands of molecules containing the sulfanilamide structure have been created since its discovery (by one account, over 5,400 permutations by 1945). They have greater effectiveness and lesstoxicity. Sulfa drugs are still widely used for conditions such asacne andurinary tract infections. They are back in favour for use on infections caused bybacteria resistant to other antibiotics.
Sulfonamides are prepared by the reaction of a sulfonyl chloride withammonia or anamine.
