Drug discovery and development

Drug discovery and development is the process by which new candidate medications are discovered and processed until they reach the market for human consumption.

The drug discovery process is a very long process that can take up to an average of 10 years. The following are the stages involved:

Discovery phase

At this stage, researchers discover new drugs for new diseases or already existing diseases by testing thousands of compounds. However, only a few compounds may seem to have possible beneficial effects. New information about the disease process may allow the researchers to design products which would treat the disease. Screening of natural product extracts from plants and microorganisms also play an important role in the discovery of new drug compounds.

Development phase
Pre-clinical studies

During pre-clinical studies, the compounds discovered during early drug discovery are refined, optimised, and thoroughly examined in a laboratory setting as well as in animal or alternative models. Studies on the absorption, distribution, metabolism and excretion mechanisms of the compounds are also done including establishing the possible mechanism of action. Before clinical trials in people can begin, sufficient evidence of safety and efficacy must be provided. The efficacy of the compounds can be compared to that of similar medications already in use.

Clinical studies
Clinical trials are composed of four phases: phase I, II, III and IV.

Phase I: In the first phase, tolerance and safety of the drug candidate is assessed in a small sample of healthy volunteers, usually numbering between 20 to 100 people. Phase I’s goal is to find out the answers to the following questions; is the drug safe? What dose can be given without side effects? How does the substance behave in the body?

Phase II: In phase II, the therapeutic effect of the drug candidate is tested on up to 500 people suffering from a specific disease. This phase not only examines the effectiveness and tolerability of the drug, but also determines the dosage.

Phase III: If the drug passes Phase II, it will be studied in a wider group of patients in Phase III clinical trials. The goal is to demonstrate that the drug has the desired effect in a large number of patients. During this stage, rare side effects may be detected. If Phase III is successful, the manufacturer can file for drug approval, which is the official license to market the drug.

Regulatory approval

The data is collected and analysed once a drug candidate has completed the clinical trials. It can then be submitted for review to the appropriate authorities. A national regulatory authority must approve a medication or vaccine before it may be sold. Only one compound out of a big number examined makes it through the clinical study phases and regulatory tests in the end.

Post-market monitoring

After obtaining marketing authorisation from the authorities, Phase IV studies (also known as Post-Marketing Surveillance Trials) are conducted. More information about the effectiveness and safety of the new medicine can be acquired. A higher number of patients using the medicine provides more data and allows for comparisons with existing treatments. These studies are used to evaluate a drug’s long-term effects.

From this write up, we can conclude that drug discovery and development is a multidisciplinary process that requires financial, human, and physical resources.

This article was contributed by Christabel Hikaambo-Mwila.

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