Editing Pharmacology (section)

==== Drug discovery ====
{{overly detailed|date=July 2019}}
[[Drug discovery]] is the field of study concerned with creating new drugs. It encompasses the subfields of [[drug design]] and [[Drug development|development]].{{fact|date=March 2025}} Drug discovery starts with drug design, which is the [[invention|inventive]] process of finding new drugs.<ref>{{cite book |doi=10.1201/b12381 |title=Textbook of Drug Design and Discovery |date=2002 |last1=Smith |first1=H. John |last2=Williams |first2=H. John |isbn=978-0-429-21928-3 |editor-first1=Tommy |editor-first2=Povl |editor-first3=Ulf |editor-last1=Liljefors |editor-last2=Krogsgaard-Larsen |editor-last3=Madsen }}{{pn|date=March 2025}}</ref> In the most basic sense, this involves the design of molecules that are complementary in [[shape]] and [[electric charge|charge]] to a given biomolecular target.<ref>{{cite web|url=https://www.chem.uwec.edu/Chem491_W09/Topic7-2.pdf|title=Introduction to Drug Design|access-date=31 October 2021|archive-date=31 October 2021|archive-url=https://web.archive.org/web/20211031021835/https://www.chem.uwec.edu/Chem491_W09/Topic7-2.pdf|url-status=live}}{{self-published inline|date=March 2025}}</ref> After a [[lead compound]] has been identified through drug discovery, drug development involves bringing the drug to the market.{{fact|date=March 2025}} Drug discovery is related to [[pharmacoeconomics]], which is the sub-discipline of [[health economics]] that considers the value of drugs.<ref>{{cite journal | vauthors = Mueller C, Schur C, O'Connell J | title = Prescription drug spending: the impact of age and chronic disease status | journal = American Journal of Public Health | volume = 87 | issue = 10 | pages = 1626–9 | date = October 1997 | pmid = 9357343 | pmc = 1381124 | doi = 10.2105/ajph.87.10.1626 }}</ref><ref>{{cite journal | vauthors = Arnold RJ, Ekins S | title = Time for cooperation in health economics among the modelling community | journal = PharmacoEconomics | volume = 28 | issue = 8 | pages = 609–13 | year = 2010 | pmid = 20513161 | doi = 10.2165/11537580-000000000-00000 }}</ref> Pharmacoeconomics evaluates the cost and benefits of drugs in order to guide optimal healthcare resource allocation.<ref>{{cite book |doi=10.1016/B978-0-12-802103-3.00034-1 |chapter=Pharmacoeconomics in Healthcare |title=Pharmaceutical Medicine and Translational Clinical Research |date=2018 |last1=Rai |first1=Mahendra |last2=Goyal |first2=Richa |pages=465–472 |isbn=978-0-12-802103-3 }}</ref> The techniques used for the [[Drug discovery|discovery]], [[Pharmaceutical formulation|formulation]], manufacturing and quality control of drugs discovery is studied by [[pharmaceutical engineering]], a branch of [[engineering]].<ref>{{cite journal| vauthors = Reklaitis GV, Khinast J, Muzzio F |date=November 2010|title=Pharmaceutical engineering science—New approaches to pharmaceutical development and manufacturing|journal=Chemical Engineering Science|volume=65|issue=21|pages=iv–vii|doi=10.1016/j.ces.2010.08.041|bibcode=2010ChEnS..65D...4R }}</ref> [[Safety pharmacology]] specialises in detecting and investigating potential undesirable effects of drugs.<ref>{{Cite journal|last=Hite|first=Mark|date=2016-06-25|title=Safety Pharmacology Approaches|journal=International Journal of Toxicology|language=en|volume=16|pages=23–32|doi=10.1080/109158197227332 |doi-access=free}}</ref><!-- drug discovery/design/development: 34092 pubmed results in 2019--><!-- pharmacoecon: 25523 pubmed results in 2019--><!-- pharmacoengineering or "pharmaceutical engineering" : 4830 pubmed results in 2019--><!-- safety pharm: 848 pubmed results in 2019-->{{AI4 | image = Drug discovery cycle.svg |class=skin-invert-image | image-bg-color = light-dark(white,transparent) | annotations = | align = right | image-width = 300 | width = 300 | height = 225 | alt = Drug discovery cycle schematic | caption =The drug discovery cycle}}

[[Drug development|Development of medication]] is a vital concern to [[medicine]], but also has strong [[economical]] and [[political]] implications. To protect the [[consumer]] and prevent abuse, many governments regulate the manufacture, sale, and administration of medication. In the [[United States]], the main body that regulates pharmaceuticals is the [[Food and Drug Administration]]; they enforce [[Technical standard|standards]] set by the [[United States Pharmacopoeia]]. In the [[European Union]], the main body that regulates pharmaceuticals is the [[European Medicines Agency|European Medicines Agency (EMA)]], and they enforce standards set by the [[European Pharmacopoeia]].

The metabolic stability and the reactivity of a library of candidate drug compounds have to be assessed for drug metabolism and toxicological studies. Many methods have been proposed for quantitative predictions in drug metabolism; one example of a recent computational method is SPORCalc.<ref>{{cite journal | vauthors = Smith J, Stein V | title = SPORCalc: A development of a database analysis that provides putative metabolic enzyme reactions for ligand-based drug design | journal = Computational Biology and Chemistry | volume = 33 | issue = 2 | pages = 149–59 | date = April 2009 | pmid = 19157988 | doi = 10.1016/j.compbiolchem.2008.11.002 }}</ref> A slight alteration to the chemical structure of a medicinal compound could alter its medicinal properties, depending on how the alteration relates to the structure of the substrate or receptor site on which it acts: this is called the structural activity relationship (SAR). When a useful activity has been identified, chemists will make many similar compounds called analogues, to try to maximize the desired medicinal effect(s). This can take anywhere from a few years to a decade or more, and is very expensive.<ref name="ReviseALChem">{{cite book |title=Revise A2 Chemistry |chapter=What's in a Medicine (WM) |chapter-url={{GBurl|4vtRp_03vFYC|pg=RA1-PA1}} |last1=Newton|first1=David| first2 = Alasdair | last2 = Thorpe | first3 = Chris | last3 = Otter | name-list-style = vanc |publisher=[[Heinemann Educational Publishers]]|year=2004|isbn=0-435-58347-6|pages=1}}</ref> One must also determine how safe the medicine is to consume, its stability in the human body and the best form for delivery to the desired organ system, such as tablet or aerosol. After extensive testing, which can take up to six years, the new medicine is ready for marketing and selling.<ref name="ReviseALChem" />

Because of these long timescales, and because out of every 5000 potential new medicines typically only one will ever reach the open market, this is an expensive way of doing things, often costing over 1 billion dollars. To recoup this outlay pharmaceutical companies may do a number of things:<ref name="ReviseALChem" />
* Carefully research the demand for their potential new product before spending an outlay of company funds.<ref name="ReviseALChem" />
* Obtain a patent on the new medicine preventing other companies from producing that medicine for a certain allocation of time.<ref name="ReviseALChem" />

The [[inverse benefit law]] describes the relationship between a drugs therapeutic benefits and its marketing.

When designing drugs, the [[placebo]] effect must be considered to assess the drug's true therapeutic value.

Drug development uses techniques from [[medicinal chemistry]] to chemically design drugs. This overlaps with the biological approach of finding targets and physiological effects.