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Drug Discovery is the process by which drugs are discovered and designed. It spans across the fields of the physical, mathematical and life sciences, as well as the medical sciences. The process of finding a new drug can be split up into several stages of discovery....
When creating a new drug, the patient should always come first. All drugs are developed to help patients overcome a disease and improve their quality of life, so new treatments must be safe, effective, and available in the shortest time possible. The process of drug development is a complex process, and as a result there are important, well-defined procedures that must be followed along the way. Here, we guide you through the main stages and explain why each is crucial.

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Target Validation
The first step in creating a drug is to identify the best targets for treating or preventing a disease. These targets are most commonly proteins - essential molecules that control how our cells function. They might be proteins integral to the human body and associated with a disease, or alien compounds that cause disease. The challenge is to identify which proteins are relevant, and to confirm their role in an illness. Read More
Hit-to-lead
Once a suitable disease target is identified, the next step is to find chemical compounds that bind to the target protein.

Laboratory scientists can compare substances that they know will bind to the target protein with other compounds that might also be suitable. Gradually, a collection of individual molecules that may possess the correct properties is built up - which often contains a combination of thousands of well-known and exotic compounds. Each of these molecules is then tested to confirm its effect on the drug target. Read More
Lead Optimisation
Once a large number of hit compounds have been whittled down, the lead compounds are refined in order to increase their safety and effectiveness.

This process, known as lead optimisation, is complex and often requires many iterations before the qualities of a lead are good enough for it be be considered for use as a drug. In fact, this stage often represents the bottleneck of a drug discovery program so, to increase the chances of success, more than one confirmed lead will usually be evaluated at this stage. The pool of candidates may even be further widened by synthesising a set of similar compounds, called analogues, which will also be tested. Read More
Pre-clinical testing
When a drug candidate is identified, further tests are carried out to ensure that the drug will be safe for patients to use.

This stage of testing has to be taken extremely seriously in order to minimize any possible risk to patients further along the process. Although a significant proportion of the testing can be conducted using computer modelling or bench-top experimentation, the complexity of disease can often only be understood through the use of animals studies. By studying the reactions of animals to compounds, researchers are able to better understand which drugs are safest and most effective. Read More
Clinical testing
Once a drug candidate has passed pre-clinical testing, it is subject to a rigorous set of clinical trials, designed to test its safety and efficacy. Clinical trials are typically split into three phases.

During Phase 1 trials, the drug is usually tested in a small group of volunteers to assess its safety, and help understand how it is metabolised by the human body. In Phase 2 trials, the drug is given to between 100-250 patients who suffer from the disease, in order to measure its efficacy and determine the optimal dose. At each of these stages, safety and side effects are closely monitored in order to accurately assess the suitability of the compound.

The data from Phase 1 and Phase 2 studies provides scientists with the evidence necessary to continue the development of the compound in larger clinical trials. Phase 3 clinical trials typically enroll over 1000 patients, and are designed to confirm the effectiveness of the drug, continue monitoring its side effects, compare it to established treatments, and allow pharmaceutical firms to develop reliable guidelines for its safe use.

Once completed, the results from clinical trials are presented to regulatory authorities, who then determine whether a drug is suitable to be released into the market to treat patients. Only if the the regulatory authorities declare a drug suitable for the market can it go on to be used in patients. Read More