Developing new drugs, whether chemicals or biological entities, is a very expensive, complex and time-consuming process. This is why when you see a new medication on the shelf, you should know that dozens of other medications did not make it. New drug discovery entails finding and identifying new candidates for testing in humans for different diseases and conditions all while ensuring these potential drugs are safe and have the required efficacy.
Studying Diseases and Conditions
The first step in drug discovery is studying disease to understand how it behaves. The disease is studied at a molecular or cellular level until everything about it is understood. Once scientists have this information, they use either target-based or phenotypic screening strategies to see which drugs will work.
Before we look at either strategy, it is important to understand that scientists use marine animals, plants, fungi, and other species to create candidate drugs that are then used in the two processes discussed above.
Target-Based Drug Discovery
Once the disease has been studied as discussed above, scientists identify targets for new treatments. The target might be a protein, gene, or another molecule instrumental to the disease progression. Interfering with the target causes the disease progression to halt and this is why its identification is so important.
Target-based drug discovery involves screening for compounds with specific activity against the targets that have been identified. The scientists involved in this process can then develop viable options known as bioactive to be used in further research.
Phenotypic screening involves the identification of molecules that have specific biological effects (the ability to alter a cell’s phenotype) in animal models or cell-based assays. Phenotypic screening was the main drug discovery tool before the advent of target-based drug discovery because it works even when there is limited knowledge of the molecular mechanism of a specific disease.
Because there is no prior knowledge and biases concerning the action and target that make up the molecular mechanism of a disease, phenotypic screening tends to have a bigger in vivo therapeutic impact.
Once the relevant molecules have been identified using either of the strategies above, they have to be tested to see if they work against the target. This is done using computer models, cells, and live animals. Testing on animals like mice and rats is very common, with options like xenograft models used for cancer research and the development of cancer drugs.
Researchers can work with companies that provide xenograft services to find xenograft models that would be perfect for the type of research they are doing.
Almost half of all compounds discovered and tested in the processes above are deemed to not have enough efficacy or not to be safe for humans. The remaining compounds are ready to be tested on humans.
The company doing the trials has to get approval from the relevant body in the testing country before human tests can start. The researchers must provide enough evidence that enough preliminary research has been done to ensure the compounds so discovered can be used on humans.
The different processes that lead to the discovery of new drugs can take years and even decades. These rigorous processes ensure that all medications that reach pharmacy shelves have the required efficacy and are safe for human use.