1932

At I.G. Farben Industrie’s Bayer & Co. in Germany, Gerhardt Domagk observes that one of the azo dyes with sulfa side chain given to him by chemist Josef Klarer (KI-695, then more potent Kl730, first dubbed Streptozon, then released as Prontosil) protected mice given lethal doses of hemolytic streptococci. Clinical trials in Germany from 1933-1935 showed the drug effective in treating Streptococcal sore throat, erysipelas, and puerperal fever/sepsis (Lesch III, 85-90). Domagk did not publish the finding, and Bayer did not release the drug, until 1935 (Hager, 133-138, 151-152; F. Ryan, 95-97; Dowling, 107), the year investigators at the Pasteur Institute determined that it was the sulfanilamide liberated from Prontosil – the sulfa side chain attached to the azo dye in Bayer’s Prontosil -- that cured bacterial infections (Hager, 169-172; F. Ryan, 106-07; Dowling, 107; Lesch III, 82). According to Ronald Hare, the Bayer team at Elberfeld knew about the action of sulfanilamide before the Pasteur Institute publication but chose to conceal it because sulfanilamide (in his 1970 book on penicillin), a simpler compound, was not covered by patents and would therefore be less profitable. Daniel Bovet and Lesch disagree, because the Bayer group was committed to the idea that therapeutic activities were linked to coloring properties in the dye molecules under test (Lesch III, 82-84) and because “the dye molecule was regarded as a whole, and sulfanilamide as a mere part” (Lesch III, 91). Rhone-Poulenc then brought Septazine, a variation on pure sulfa, to the market in May, 1936 (172); Britain’s May & Baker introduced Sulfapyridine in 1938; and IG obtained patent for Marfanil (effective in treatment of anaerobic infections, esp. gas gangrene) in Oct, 1941 (Lesch III, 96-97),