History of aspirin mid-eighteenth century. By the nineteenth century pharmacists were experimenting with and prescribing a variety of chemicals related to salicylic acid, the active component of willow extract. In 1853, chemist Charles Frédéric Gerhardt treated acetyl chloride with sodium salicylate to produce acetylsalicylic acid for the first time; in the second half of the nineteenth century, other academic chemists established the compound's chemical structure and devised more efficient methods of synthesis. In 1897, scientists at the drug and dye firm Bayer began investigating acetylsalicylic acid as a less-irritating replacement for standard common salicylate medicines, and identified a new way to synthesize it.
Aminohippuric acid was given along with penicillin in order to prolong the time penicillin circulated in the blood. Because both penicillin and "para"-aminohippurate compete for the same transporter in the kidney, administering "para"-aminohippurate with penicillin decreased the clearance of penicillin from the body by the kidney, providing better antibacterial therapy. Transporters found in the kidney eliminate organic anions and cations from the blood by moving substances, in this case, drug metabolites, from blood into urine. In vultures, the NSAID diclofenac, which is extraordinarily toxic to vultures, interferes with the renal transport of uric acid via the PAH channel. p"K" = 3.83 Aminohippuric