DRUG DISCOVERY

Pre-discovery

1. Disease Identification

Before any potential new medicine can be discovered, scientists work to understand the disease to be treated as well as possible, and to unravel the underlying cause of the condition. They try to understand how the genes are altered, how that affects the proteins they encode and how those proteins interact with each other in living cells, how those affected cells change the specific tissue they are in and finally how the disease affects the entire patient. This knowledge is the basis for treating the problem.

2.Target Identification

The definition of "target" itself is something argued within the pharmaceutical industry. Generally, the "target" is the naturally existing cellular or molecular structure involved in the pathology of interest that the drug-in-development is meant to act on. 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 therapeutics. In an estimate from 2011, 435 human genome products were identified as therapeutic drug targets of FDA-approved drugs.

"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.

3.Finding A Lead Compound

Armed with their understanding of the disease, scientists are ready to begin looking for a drug. They search for a molecule, or  “lead compound,” that may act on their target to alter the disease course. If successful over long odd sand year soft testing, the lead compound can ultimately become a new  medicine.

There are a few ways to find a lead compound

• Natural sources ( plant, animal, Micro-organisms etc)
• Synthetics ( Using Chemical Banks)
• Enhance the side effects of other drugs. e.g Sulphonamide used as diurectics
• Seredipity ( By chance e.g penicillin discover
• Use structural similarity to a natural ligand
• Computer-Assisted Drug Design

4. Lead optimization

Structure of lead is altered to improve its properties.This is called as lead optimization.

Now drug development process starts.

 

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