6. Gertrude B. ElionGertrude Elion was an American biochemist and pharmacologist who won a Nobel Prize in Physiology or Medicine in 1988 for new principles of drug treatment.
Alongside colleagues George Hitchings and Sir James Black, Elion created a number of drugs that led to the development of the AIDS drug AZT. She also was pivotal to developing the first immunosuppressive drug, azathioprine, and the first antiviral drug for treating herpes, according to a Wikipedia article about her.
Elion and Hitchings noticed the difference in biochemistry between normal human cells and pathogens to develop drugs that could reduce or stop pathogens from multiplying without harming host cells. This discovery led to a number of drugs being developed to treat diseases like leukemia, malaria, organ transplant rejection and herpes.
She is also credited with inventing Purinethol for treating leukemia; the immunosuppressive agent Imuran; Zyloprim for gout; Daraprim for malaria; Proloprim and Monoprim for meningitis, septicemia and urinary and respiratory bacterial infections; Zovirax for viral herpes; and Nelarabine for cancer treatment.