Aspirin to salicylic acid, the active component of willow extract. In 1853, chemist Charles Frédéric Gerhardt treated sodium salicylate with acetyl chloride 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. By 1899, Bayer had dubbed this drug Aspirin and was selling it around the world. The word
Technetium (99mTc) medronic acid Technetium (99mTc) medronic acid Technetium (Tc) medronic acid (MDP) is a pharmaceutical product used in nuclear medicine to localize bone metastases as well as other diseases that can alter the natural turn-over in the bone by bone scintigraphy. The drug is a complex of medronic acid, the simplest bisphosphonate, with technetium-99m (Tc), a radionuclide that emits gamma rays. The exact structure of the complex is not known. Tc-MDP must be prepared in a radiopharmacy. It is usually supplied as a "cold kit" to which radioactive Tc from a generator is added. Kit composition may vary between suppliers, but contents typically