Firdous's blog: History of pharmacology

Firdous's blog: History of pharmacology: History of Pharmacology ·         Since time immemorial, medicaments have been used for treating disease in humans and animals. The he...

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Firdous's blog: What is a Drug?

Firdous's blog: What is a Drug?: A drug can be defined as a chemical substance of known structure, other than a nutrient or as essential dietary ingredient, which when adm...

What is a Drug?

A drug can be defined as a chemical substance of known structure, other than a nutrient or as essential dietary ingredient, which when administered to a living organism, produces a biological effect.
Drugs may be synthetic chemicals obtained from plants or animals, or products of genetic engineering. A medicine is a chemical preparation, which usually, but not necessarily, contains one or more drugs, administered with the intention of producing therapeutic effect. Medicines usually contains other substances (excipients, stabilisers, solvents, etc.) besides the active drug, to make them more convenient to use. To count as a drug, the substance must be administered as such, rather than released by physiological mechanisms. Many substances, such as insulin or thyroxine, are endogenous hormones but are also drugs when are administered intentionally. Many drugs are not used in medicines but are neverthless useful research tools. In everyday parlence, the word drug is often associated with addictive, narcotic or mind-altering substances - an unfortunate negative connotation that tends to bias uninformed opinion against any form of chemical therapy. Even poisons fall strictly within the definition of drugs. 

History of pharmacology

History of Pharmacology

·        Since time immemorial, medicaments have been used for treating disease in humans and animals. The herbals of antiquity describe the therapeutic powers of certain plants and minerals. Belief in the curative powers of plants and certain substances rested exclusively upon traditional knowledge, that is, empirical information not subjected to critical examination.

·        History of pharmacology, knowledge of drugs and their use in disease is as old as history of mankind.

·        But as a science pharmacology is quite young.

·        Primitive men gathered the knowledge of healing and medicine by observing the nature, noticing animals while ill and by personal experience after consuming certain herbs and berries as remedies.

·        Hippocrates (460 B.C-377B.C) “The Father of Medicine” was the first to attempt to separate the practice of medicine from religion and superstition, developed his pledge of proper conduct for doctors “I WILL USE TREATMENT TO HELP THE SICK ACCORDING TO MY ABILITY AND JUDGEMENT, BUT NEVER WITH THE VIEW TO INJURY AND WRONG DOING… INTO WHATSOEVER HOUSES I ENTER. I WILL ENTER TO HELP THE SICK.”

·        Ebers papyrus describes more than 700 drugs in extensive pharmacopoeia of that civilization. Included in this are: beer, turpentine, berries, lead, salt and crushed precious stones, etc.(Egyptian remedies)

·        The Ebers papyrus (c 1550BC) is an ancient Egyptian medical treatise. It covers both practical and magical advice. There are over 700 different drugs described in the papyrus (papyrus=writing and painting implement). Some are useful such as opium for pain. Other things in the papyrus seems rediculus. An example of that is tapping a person on the head with a fish if they have a migraine. Aside from covering a large number of treatments the papyrus also has information on a broad range of ailments from intestinal complaints and eye problems to depression or other mental disorder.

·        Susrutha and Charaka Samhita: Ancient hindu medical text describes respectively 760 herbs and 650 drugs of animals, plants and mineral origins are used.

IDEA

·        Claudius Galen (129–200 A.D.) first attempted to consider the theoretical background of pharmacology. Both theory and practical experience were to contribute equally to the rational use of medicines through interpretation of observed and experienced results. “The empiricists say that all is found by experience. We, however, maintain that it is found in part by experience, in part by theory. Neither experience nor theory alone is apt todiscover all.”

·        The Impetus Theophrastus von Hohenheim (1493– 1541 A.D.), called Paracelsus, began to quesiton doctrines handed down from antiquity, demanding knowledge of the active ingredient(s) in prescribed remedies, while rejecting the irrational concoctions and mixtures of medieval medicine. He prescribed chemically defined substances with such success that professional enemies had him prosecuted as a poisoner. Against such accusations, he defended himself with the thesis that has become an axiom of pharmacology: “If you want to explain any poison properly, what then isn‘t a poison? All things are poison, nothing is without poison; the dose alone causes a thing not to be poison.”

·        Father of toxicology

·        Paracelsus was one of the first medical professors to recognize that physicians required a solid academic knowledge in the natural sciences, especially chemistry. Paracelsus pioneered the use of chemicals and minerals in medicine. From his study of the elements, Paracelsus adopted the idea of tripartite alternatives to explain the nature of medicine, taking the place of a combustible element (sulphur), a fluid and changeable element (mercury), and a solid, permanent element (salt). The first mention of the mercury-sulphur-salt model was in the Opus paramirum dating to about 1530. Paracelsus believed that the principles sulphur, mercury, and salt contained the poisons contributing to all diseases. He saw each disease as having three separate cures depending on how it was afflicted, either being caused by the poisoning of sulphur, mercury, or salt. Paracelsus drew the importance of sulphur, salt, and mercury from medieval alchemy, where they all occupied a prominent place. He demonstrated his theory by burning a piece of wood. The fire was the work of sulphur, the smoke was mercury, and the residual ash was salt. Paracelsus also believed that mercury, sulphur, and salt provided a good explanation for the nature of medicine because each of these properties existed in many physical forms. The tria prima also defined the human identity. Salt represented the body; mercury represented the spirit (imagination, moral judgment, and the higher mental faculties); sulphur represented the soul (the emotions and desires). By understanding the chemical nature of the tria prima, a physician could discover the means of curing disease. With every disease, the symptoms depended on which of the three principals caused the ailment. Paracelsus theorized that materials which are poisonous in large doses may be curative in small doses; he demonstrated this with the examples of magnetism and static electricity, wherein a small magnet can attract much larger metals.

EARLY BEGINNINGS

·        Johann Jakob Wepfer (1620–1695) was the first to verify by animal experimentation assertions about pharmacological or toxicological actions. “I pondered at length. Finally I resolved to clarify the matter by experiments.”

·        Wepfer made important contributions in the fields of experimental pharmacology and toxicology. He conducted experiments on the toxicity of water, hemlock, hellebore, monkshood and warned against the usage of arsenic, antimony, and mercury in medicine. In the fields of pharmacology/toxicology he published an influential work on water and poison hemlock called Cicutae aquaticae historia et noxae (1679). This contained the first reports of toxicity of plants from the Cicutagenus, ultimately attributed to compounds such as cicutoxin and oenanthotoxin. Since 2005 an annual award for stroke research, named after Wepfer, is awarded at the European stroke conference.

FOUNDATION

·        Rudolf Buchheim (1 March 1820 – 25 December 1879) was a German pharmacologist born in Bautzen (Budziszyn).

In 1845 he earned his doctorate from the University of Leipzig and shortly after became an associate professor of pharmacology, dietetics, history of medicine and medical literature at the University of Dorpat. In 1849 he was chosen as a full professor of pharmacology. While at Dorpat he created the first pharmacological institute at that school. In 1867 he became professor of pharmacology and toxicology at the University of Giessen.

·        Buchheim is remembered for his pioneer work in experimental pharmacology. He was instrumental in turning pharmacology from an empirical study of medicine into an exact science. He introduced the bioassay to pharmacology, and created a methodology for determining the quantitative and medical aspects of chemical substances.

·        While a student in Leipzig, Buchheim translated Jonathan Pereira's (1804–1853) handbook of pharmacology from English into German. He also edited the book, eliminating obsolete and ineffectual medicines and practices, while adding updated information, including a chapter of his own called Art der Wirkung ("The Pharmacological Action"). He was also the author of a well-received textbook on pharmacology, titled Lehrbuch der Arzneimittellehre (3rd edition, 1878).

·        Lacking outside funding, Buchheim built the world’s first pharmacology laboratory at his own expense in the basement of his house.

·        Today at university of Giessen is the Rudolf Buchheim Institute of Pharmacology.

·        A well-known student of his was chemist Oswald Schmiedeberg (1838–1921), who was to become the "founder of modern pharmacology". Today at the University of Giessen is the Rudolf Buchheim Institute for Pharmacology.

CONSOLIDATION – GENERAL RECOGNITION

·        Oswald Schmiedeberg (1838-1921) was a Baltic German pharmacologist. He is sometimes referred to as the “Father of Modern Pharmacology.”

·        Oswald Schmiedeberg obtained his medical doctorate in 1866 with a thesis on the measurement of chloroform in blood.

·        In 1872, he became the professor of pharmacology at the University of Strassburg.

·        Oswald Schmiedeberg together with his many disciples (12 of whom were appointed to chairs of pharmacology), helped to establish the high reputation of pharmacology.

·        Fundamental concepts such as structure-activity relationship, drug receptor, and selective toxicity emerged from the work of, respectively, T. Frazer (1841– 1921) in Scotland, J. Langley (1852– 1925) in England, and P. Ehrlich (1854–1915) in Germany.

·        Alexander J. Clark (1885–1941) in England first formalized receptor theory in the early 1920s by applying the Law of Mass Action to drug-receptor interactions.

·        Together with the internist, Bernhard Naunyn (1839–1925), Schmiedeberg founded the first journal of pharmacology, which has since been published without interruption.

·         The “Father of American Pharmacology”, John J. Abel (1857–1938) was among the first Americans to train in Schmiedeberg‘s laboratory and was founder of the Journal of Pharmacology and Experimental Therapeutics (published from 1909 until the present).

Status Quo

After 1920, pharmacological laboratories sprang up in the pharmaceutical industry, outside established university institutes. After 1960, departments of clinical pharmacology were set up at many universities and in industry.