Karl Christian Friedrich Pfizer (German: [kaʁl ˈpfɪtsɐ]; March 22, 1824 – October 19, 1906), known as Charles Pfizer, was a German-American businessman and chemist who co-founded the Pfizer pharmaceutical company with his cousin, Charles F. Erhart, in 1849, as Chas. Pfizer & Co. Inc.
Friedrich Bayer (born Friedrich Beyer, 6 June 1825 in Barmen now Wuppertal – 6 May 1880 in Würzburg) was the founder of what would become Bayer, a German chemical and pharmaceutical company. He founded the dyestuff factory Friedrich Bayer along with Johann Friedrich Weskott in 1863 in Elberfeld, a flourishing city in the early industrialised region of the Wuppertal or Wupper Valley.
Friedrich Bayer changed the spelling of his surname from Beyer in his early twenties, due to the publicity gained by a fraudulent merchant from Leipzig bearing the same name. Friedrich Beyer from Barmen feared that the bad reputation of his namesake could damage his business and consequently changed his surname to Bayer.
Paul Adriaan Jan, Baron Janssen (12 September 1926 – 11 November 2003) was a Belgian physician. He was the founder of Janssen Pharmaceutica, a pharmaceutical company with over 20,000 employees which is now a subsidiary of Johnson & Johnson.