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Revision as of 15:59, 25 November 2005 by Dogbertd (talk | contribs) (→Targets: New and Established)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff)In medicine, biotechnology and pharmacology, drug discovery is the process by which drugs are discovered and/or designed.
In the past most drugs have been discovered either by identifying the active ingredient from traditional remedies or by serendipitous discovery. A new approach has been to understand how disease and infection are controlled at the molecular and physiological level and to target specific entities based on this knowledge.
The process of drug discovery involves the identification of candidates, synthesis, characterization, screening, and assays for therapeutic efficacy. Once a compound has shown its value in these tests, it will begin the process of drug development prior to clinical trials.
Despite advances in technology and understanding of biological systems, drug discovery is still a long process with low rate of new therapeutic discovery. Information on the human genome, its sequence and what it encodes has been hailed as a potential windfall for drug discovery, promising to virtually eliminate the bottleneck in therapeutic targets that has been one limiting factor on the rate of therapeutic discovery. However, data indicates that "new targets" as opposed to "established targets" are more prone to drug discovery project failure in general. This data corroborates some thinking underlying a pharmaceutical industry trend beginning at the turn of the twenty-first century and continuing today which finds more risk aversion in target selection among multi-national pharmaceutical companies.
Targets: New and Established
The definition of "target" itself is something debated within the pharmaceutical industry. However, the distinction between a "new" and "established" target can be made without a full understanding of just what a "target" is. This distinction is typically made by pharmaceutical companies engaged in discovery and development of small molecule therapeutics.
"Established targets" are those for which there is a good scientific understanding, supported by a lengthy publication history, of both how the target functions in normal physiology and how it is involved in human pathology. This does not imply that the mechanism of action of drugs that are thought to act through a particular established targets is fully understood. Rather, "established" relates directly to the amount of background information available on a target, in particular functional information. The more such information is available, the less investment is (generally) required to develop a therapeutic directed against the target. The process of gathering such functional information is called "target validation" in pharmaceutical industry parlance. Established targets also include those that the pharmaceutical industry has had experience mounting drug discovery campaigns against in the past; such a history provides information on the chemical feasibility of developing a small molecular therapeutic against the target and can provide licensing opportunities and freedom-to-operate indicators with respect to small molecule therapeutic candidates.
In general, "new targets" are all those targets that are not "established targets" but which have been or are the subject of drug discovery campaigns. These typically include newly discovered proteins, or proteins whose function has now become clear as a result of basic scientific research.
The majority of targets currently selected for drug discovery efforts are proteins. Two classes predominate: G-protein-coupled receptors (or GPCRs) and protein kinases.
Screening and Design
The process of finding a new drug against a chosen target usually involves high-throughput screening, wherein large libraries of chemicals are tested for their ability to modify the target. For example, if the target is a novel GPCR, compounds will be screened for their ability to inhibit or stimulate that receptor (see antagonist and agonist): if the target is a kinase, the chemicals will be tested for their ability to inhibit that kinase.
See also
- Protein structure prediction
- Drug design
- Rational drug design
- Bioinformatics
- Cheminformatics
- Biomedical informatics
- Orphan drug
- Physiologically-based pharmacokinetic modelling
External links
Notes and references
- this requires substantiation with one or more reputable sources from the time of enthusiasm following "completion" of the human genome sequence
- . October, 2005.
{{cite news}}: Check|url=value (help); Check date values in:|date=(help); Unknown parameter|org=ignored (help) - Personal communication. this requires substantiation with one or more reputable sources reporting on industry trends in 2003–2005
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