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Creation

Medicinal chemistry a subject area of science that deals with the use of techniques and theories of chemistry, molecular chemistry, physics, biology, genetics, information technology and various other fields to discover and synthesise drugs for use in human health.

The Origins of Medicinal Chemistry

Human civilisation has been cataloguing various plants and substances by their perceived medicinal qualities since almost as far back as written records go.

The first fully developed written records that are currently known are clay tablets from Mesopotamia (@todo, deteails and photos) from around 2600 BC which include lists of substances used for traditional medical purposes, later Chinese and Egyptian records of substances used exist from these early periods.

However the serious scientific study of substances and their medicinal properties really took off after the discovery of Penicillin by Alexander Fleming in 1929.

Since the a series of break through discoveries and theories have enabled the systematisation of the process of discovery of new drugs to treat disease.

Identification of the structure of DNA, and further techniques to categorise and manipulate genetic molecules opened a new avenue of candidates for drug discovery.

Timeline of Medicine

Main article on Medicinal Chemistry Timeline of medicine

While there are references to medicinal substances from 2600BC, there are references to the use of chemicals for their effects on the body as far back as 4500BC, in the form of poisons.

    "Gula, the woman, the mighty one, the prince of all women
    His seed with a '''poison not curable'''
    Without issue; in his body may she place
    All the days of his life,
   ''' Blood and pus like water may he pour forth'''."

http://www.portfolio.mvm.ed.ac.uk/studentwebs/session2/group12/ancient.htm

What is a Drug?

Drugs can be differientiated from nutrients

some nutrients can be considered drugs (Iron for treating aneamia)

Drugs can be synthetic or natural


Molecule of the Month

Approaches in Medicinal Chemistry

The major causes of death in the "developed" world are Cancer, Circulatory disease, and respiratory disease. Hence a great deal of research and resource are directed at finding drugs and treatments to provide vaccines, Ameliorative, and therapy.

Cancer recently because the number 1 causes of death for UK citizens, over taking Heart disease (in 2010 ONS annual mortality report)

Drug discovery is often categorised for academic purposes as one of the following approaches

1. irrational
2. rational
3. ... @TODO


The study of epigenetic modification has provided target candidates for the manipulation of genetic expression

Medicinal chemistry is the study of the effects of drug molecules and the molecular mechanisms by which they act. It is a multidisciplinary subject with cross over into cell biology, pharmacology and statistics.

It is typically dedicated to the study of substances and techniques relating to the use of drugs to effect aspects of the human body.


Language of Medicinal Chemsitry

  • Molecular structures
  • functional groups
  • reaction patterns


Finding new uses for known substances

p53 is an important protein in the regulation of cell processes, and apoptosis and is a major target for drugs to treat cancer.

Cisplatin is an important drug for the treatment of cancer.
==Drug administration==
The main routes of administration of medicinal substances into the human body can be categorised as follows


  1. oral or rectal
    #percutaneous (through the skin)
    #Intravenous
    Intramuscular
    intrathecal (entry via the spine or brain under the arachnoid membrane)
    inhalation


Important concepts in Medicinal Chemistry

ADME: Absorption, Distribution, Metabolism and Excretion

highly dependent on context, environment, genetics


Sublingual absorption

technique to get drug into the circulatoriy system while avoiding the gut



main article on ADME


Quantitative metrics associated with drugs

Pharmacokinetics defines 4 fundemental paramters

Bioavailability
Clearance
Volume of Distribution
Half-life


C_max t max AUC

Getting drugs across the cell membrane

Carrier Mediated Drug transport

when some drug is not soluble in lipids, it requires some transport to pass into the target cell


Also

target receptors

Ligands


Cation

hepatocytes

OCT1

OCT2

lipid solubility

Drug Overdose and Elimination

Circumstances such as overdose and unwanted side effects can require a thorough knowledge of the elimination of a particular drug molecule under the various appropriate parameters.

For example some drugs such as morphine are resistent to being eliminated from the body using haemodyalisis because of the characteristics of the molecule. [1]


recommended International non-proprietary names (rINN)

WHO naming scheme

References

  • Patrick, G. L. (2009) An Introduction to Medicinal Chemistry
    (4th edn), Oxford, Oxford University Press.


  • Rang, H. P., Dale, M. M., Ritter, J. M., Flower R. J. and Henderson G.,
    (2012) Pharmacology (7th edn),
    Edinburgh, Churchill Livingstone.
  1. Rang, H. P., Dale, M. M., Ritter, J. M., Flower R. J. and Henderson G., (2012b) ‘Drug elimination and pharmacokinetics’ in Pharmacology (7th edn), Edinburgh, Churchill Livingstone, pp. 115–22.
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