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Sulpha or sulphonamide is one of the first microbial inhibitors; a bacterial enzyme synthesises vitamin folic acid, discovered in 1930 by the German scientist Domagk. This discovery was made by the red dye known as prontosil. The latter was biologically inactive while proving the opposite in the body. Red dye was used to treat an infant (aged 10 months) with a deadly infection. The biological efficacy of the dye to reductive cleavage Azo-forming agent for sulfanilamide - the real responsible for biological activity. It should be noted that all sulfonamides are derived from sulfanilamide (Zubay and Parson, 1995). The latter is similar to aminobenzoic acid that bacteria need to build folic acid, so sulfa drugs are effective in inhibiting the action of bacteria (Talaro, 1996). Differences in the functional group (SO2NHR) R result in different physiological, chemical and pharmacological properties of these drugs (Lowe and Hirschrman, 1984). Compensation for the sulfuric nitrogen atom leads to the production of stronger sulfanilamide acid (Goth, 1981) and compensation with the -SO3H group instead of -SO2NH2 for sulfonamide leads to the elimination of biological efficacy (Wilson and Gisvold’s, 1989). The sulfonamides that possess the freep-amino group show only effective against bacteria, which have compensation in the free amino group become effective only as compensation is removed within the body and this is why Prontosil is ineffective outside the body.


Sulpha Sulphonamide Microbial inhibitors

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How to Cite
Amal H. Mhemeed. (2019). A Review on Sulpha Drugs (One of The First Microbial Inhibitors). International Journal of Research in Pharmaceutical Sciences, 10(1), 241-244. Retrieved from