Ehrlich's Salvarsan for Syphilis

Paul Ehrlich wanted chemicals that would seek out one kind of microbe and spare the patient. He called the idea chemotherapy and the ideal drug a magic bullet. In 1906 he moved his laboratory to the Georg Speyer Haus near Frankfurt, close to the dye manufacturers, and his team began working through arsenic compounds, starting from one called atoxyl.

The team included the organic chemist Alfred Bertheim and the bacteriologist Sahashiro Hata, and it widened the search to spirochetes, recently identified as the cause of syphilis. Some 300 syntheses and three years later came arsphenamine, the 606th preparation tested in Ehrlich's laboratory. Two assistants had set it aside as useless. Hata repeated the tests and found it better than every other drug tried, and Ehrlich was angry about the earlier dismissal. It was tried first in rabbits infected with syphilis and then in patients, including some with the dementia of the disease's final stage, several of whom recovered.

Ehrlich did not release it at once. He arranged carefully recorded clinical studies by a small group of doctors, among them Konrad Alt at Uchtspringe, and some 65,000 doses had been given to more than 20,000 patients before the drug went on sale as Salvarsan in 1910.

It was a difficult drug. It came as a fine yellow powder that had to be packed under carbon dioxide to keep it from oxidizing, fever and rigors sometimes followed an injection, there were fatal cases, and when war cut off German supplies, the quality of British and French versions was disputed. Ehrlich's compound 914, Neosalvarsan, was more soluble and contained less arsenic. Salvarsan was used against syphilis until the 1940s.