Question

Explain the history of chemistry in medicine in 5-6 paragraphs with 1 or 2 examples. Write in essay format with a conclusion. (prefer typed easier to read)

Answer 1

Origins of Medicinal Chemistry: (very old history) 3500 BC - Sumerians report use of opium, 3000 BC - Chinese report use of ma huang (ephedra). Greek culture: Hippocrates- followed the teachings of Aristotle; focus is on the soul. Galen- followed the teachings of Plato; focus is on experiment- believed the whole could be explained by the parts. Renaissance period: Doctors were humanists- followers of Hippocratestreat the soul and the body will heal. Initially, there were no relationships with alchemy. Paracelsus (1493-1541)- adopted teachings of Galen; urged alchemists to discover the chemical essence of herbal drugs and to develop chemical medicines- particularly those composed of inorganic compounds (mercury, lead, antimony). France (1560)- courts forbid the use of chemistry in medicines even though paracelsians are gaining in popularity - much controversy. In 1793, Faureroy & Vauquehin split from the monarchycontrolled bodies and establish the Ecole Supurieure de Pharmacie- 1st to incorporate chemistry into the pharmacy curriculum. Develop research to find the active principles in plant-based drugs. 1817 - Sertürner publishes work demonstrating that the narcotic principle of opium is basic (alkaline) and, thus, it will form salts with acids- names the principle “morpheus”. Gay-Lussac predicts that other alkaline plant extracts will have useful medical properties- changes name of morpheus to morphine. 1818 - Meissner proposes the general term alkaloids. 1853 - Henry How proposes that there are “functional groups” that can be chemically modified to alter reactivities….

Fraser and Brown make quaternary salts of many different alkaloids (i.e, morphine, strychnine, nicotine) and find that all exhibit curare-paralyzing activities- propose that quaternary salts have curariform activity. Stimulated by Fraser and Brown’s results, Alder and Wright treat morphine with various organic acids- synthesize diacetylmorphine. 1898- E. Merck of Darmstadt markets Dionin (ethyl ether of morphine) as a cough sedative. Pierce tests diacetylmorphine and finds it be much more potent than morphine- thus, smaller doses can be given, which lowers toxicity. In 1820 Pelletier isolated quinine from cinchona bark- by 1826 his group is producing 3600 kg/yr of pure quinine, which is used instead of cinchona extracts to treat malaria- birth of the pharmaceutical industry.

1840’s - ether, chloroform, and nitrous oxide move from being party drugs to anesthetics - begins the search for other hypnotics 1869 - Bucheim develops chloral hydrate, an oral compound that exhibits hypnotic properties- he argues that it produces chloroform in the blood while von Mering correctly postulates that it produces trichloroethanol.

F. Bayer & Co. markets its first successful pharmaceutical, sulphonal, a hypnotic produced from acetone. Based on sulphonal, von Mering suggests that a carbon with two ethyl groups should be a good hypnotic- makes diethyl acetyl urea and then diethylbarbituric acid.

1875- Carl Buss isolates salicylic acid from Spirea ulmaria and shows that it is an effective antipyretic- however, it is unpalatable and causes gastric distress.1883- von Nencki makes a salicylate ester with phenol, salol- it has very poor solubility but it is better tolerated. It is hydrolyzed slowly in the small intestine to give salicylic acid- the first sustained release drug. 1890s - Hoffman at Bayer tests acetyl salicylic CH3 acid and finds it to be better tolerated- names it aspirin as in “a” for acetyl and “spirin” for Spirea. It is rapidly hydrolyzed in the gut to give active salicylic acid- it is a “pro-drug”. Phenazone was synthesized in 1884 and was the most popular drug world-wide until it was taken over by aspirin in the early 1900s- in addition to being an antipyretic, it also cured headaches- a new market was born…

1902- Ritsert synthesizes benzocaine but it is too non-polar to dissolve in water. Braun adds a polar amino group from adrenaline to give procaine (novocaine)- addition of a butyl group gives tetracaine with greatly extended duration. In 1935 isogramine is isolated and found to be a very potent local anesthetic.In 1946 Löfgren synthesizes lidocaine modeled after isogramine- coins the concept of an “isostere”. This remains the most commonly used local anesthetic. Addition of a butyl group gives the long lasting (~ 8 hours) bupivacaine, which is used for epidural anesthesia during childbirth.

The word ‘drug’ is probably of Arabic origin and first appeared in Old German as drog, ¨ referring to a type of powder. Indeed, the first pharmaceuticals were obtained from the vegetable kingdom as the dried parts of plants, herbs, and shrubs. According to Wikipedia, the etymology of the word ‘drug’ is the Old French word drogue or the Dutch word droog, both of which refer to dry barrels containing herbs.

Nature has provided a rich source of pharmacologically active chemical substances produced by plants, fungi, insects, and reptiles. Biosynthesis of these natural toxins functioned as a chemical self-defence mechanism and protected the species from being eaten by predators. Accordingly, these xenobiotics have been around since the dawn of history. The first human beings, in their continuous quest for food and survival, must have experienced the effects of these substances, for better or for worse. Crude extracts from wild plants and shrubs constituted the first herbal medicines that were used for the relief of pain and suffering, to heal wounds, and to treat all types of maladies. Foremost among these natural products was the juice obtained from the opium poppy plant (papaver somniferum) dating from ∼3000 BC that contained the all powerful painkiller, morphine.

The first synthetic drugs: The doyen among German organic chemists during much of the nineteenth century was Justus von Liebig (1803–1872), the renowned Professor of Chemistry in Munich. One of his many discoveries was the volatile liquid chloroform (CHCl3), which ater became important as a general anesthetic drug. The use of chloroform as a volatile anesthetic in surgery is credited to a Scottish physician James Young Simpson (1811–1870). Simpson demonstrated the benefits of chloroform to deaden the pain associated with child birth and one of his first patients in 1872 was none other than Queen Victoria of England. In 1832, Liebig also prepared chloral hydrate and showed that in alkaline solution it was converted into chloroform and formic acid. This prompted the German physician and pharmacologist Oscar Liebreich (1839–1908) to investigate whether the same reaction might occur directly in the blood, which would mean that chloral hydrate might also be useful anesthetic in the same way as chloroform. Other early drugs used as sedativehypnotic include bromide salts, paraldehyde, and urethanes, although these were made more or less redundant when the barbiturate class of drugs appeared in the first decade of the twentieth century.

Barbiturates:Barbiturates represent a remarkable class of therapeutic agents and function as sleeping aids, anaesthetics, and anticonvulsants. They entered the pharmacopoeia in the first decade of the twentieth century. The parent compound of barbiturates, barbituric acid, was synthesized in 1864 by Adolf von Baeyer (1835–1917) as part of research for his thesis (habilitation).

The first analgesics and antipyretics: The first synthetic drugs and, indeed, the entire pharmaceutical industry can be traced to the manufacture of textiles and synthetic dyes, as exemplified by mauveine (mauve), which was discovered by a young British chemist William Henry Perkin (1838–1907). An example of one of the many aromatic compounds derived from coal-tar was naphthalene, which was used as an intestinal antiseptic for, among other things, the irradiation of worms. When a patient with this condition who also happened to be suffering from a fever received naphthalene, the fever was cured but not the worms.

Aspirin - a wonder drug: This historical account of early drug discovery of mild analgesics and antipyretics would not be complete without mentioning acetylsalicylic acid, better known around the world as Aspirin. Many plants, shrubs, and trees of the Spiraea genus contain salicin, a naturally occurring glycoside of salicyl alcohol, which after hydrolysis and oxidation gives salicylic acid.

Nowdays medicinal chemistry and pharmaceutical chemistry are disciplines at the intersection of chemistry, especially synthetic organic chemistry, and pharmacology and various other biological specialties, where they are involved with design, chemical synthesis and development for market of pharmaceutical agents, or bio-active molecules. It includes synthetic and computational aspects of the study of existing drugs and agents in development in relation to their bioactivities (biological activities and properties), i.e., understanding their structure-activity relationships (SAR). At the biological interface, medicinal chemistry combines to form a set of highly interdisciplinary sciences, setting its organic, physical, and computational emphases alongside biological areas such as biochemistry, molecular biology, pharmacognosy and pharmacology, toxicology and veterinary and human medicine; these, with project management, statistics, and pharmaceutical business practices, systematically oversee altering identified chemical agents such that after pharmaceutical formulation, they are safe and efficacious, and therefore suitable for use in treatment of disease.