Updated: Nov 28, 2020
by Andrew Gao
Pharmacies across the world are stocked with thousands of different medicines, each with unique, and sometimes quite abstract, names (Think Idarucizumab or Levetiracetam). But what we often take for granted as just appearing on shelves, there’s actually tremendous work going on behind the scenes and in the lab. From its initial conception to popping up on shelves, a new drug goes through several intensive processes. In this article, you’ll learn about the steps of drug discovery. Drug discovery is the process through which new medications are discovered.
One of the most famous drugs, penicillin, an antibiotic, was discovered in 1928 by Alexander Fleming… accidentally. The Scottish scientist noticed that there were areas on his Petri dishes where no bacteria would grow, specifically the regions surrounding a Penicillium mold. He deduced that the mold was releasing antibacterial substances, which was named penicillin, and his discovery helped lead to the mass adoption of penicillin as a miracle drug, a “silver bullet”, that helped countless people with life-threatening infections. Penicillin is now considered the first modern antibiotic. Although there are indications of fungi and molds being used to treat infections in many cultures, such as Ancient Egypt, Fleming was the first to understand the scientific mechanisms behind mold and isolate penicillin.
However, although this miracle breakthrough may make drug discovery seem easy, Fleming had a rare stroke of luck. Today, as drugs become more and more complex, it’s no longer very possible for scientists to just stumble upon a miracle drug serendipitously. There are a variety of methods researchers use to discover new potential medicines. For example, new insights into a disease yielded by other research can give scientists new ideas or targets to treat that disease. For example, if protein A was found to be disrupting the immune system, scientists could develop a drug that would target and fix protein A or replace it. A different, more brute force method, is testing a plethora of compounds on a variety of diseases and seeing “what works”. Scientists observe large quantities of results to deduce which compound had effects on which diseases. Another way of drug discovery, similar to Fleming’s “stroke of luck”, is that during clinical trials of existing medicines, the medicines may have unexpected results that would be helpful in treating a separate disease. Scientists can then take that medicine and try to adapt it to a new purpose. Finally, innovative technologies, such as genome sequencing and microscopic robots that travel inside the body, provide scientists new tools for treatment. Powerful spectrophotometers and techniques like high-performance liquid chromatography also help scientists isolate and analyze specific compounds. Recently, new robotic machines have made it possible to assay thousands of compounds at a time.
Through these steps, many compounds are identified as candidates. Scientists then begin to filter out a majority of these compounds and choose the most promising ones. The next part of the drug discovery process is to conduct extensive trials on multiple aspects of the potential drugs. Scientists study how the drug is absorbed in the body, the exact mechanisms that make it work, the optimal dosage, the effectiveness of the drug, and much more. They also make sure to ensure the safety of the drug, checking for potential side effects and adverse effects. Frequently, tests are conducted on animals, although there is considerable debate over ethicality.
Overall, the drug discovery and development process is extremely costly. The cost of drug development is estimated to be over 2500 million dollars and can take 10 years.
Going back to Fleming’s discovery of penicillin, even then, the drug development wasn’t just luck. Much more rigorous research had to be conducted before pure, stable penicillin could be extracted. In fact, Fleming himself was never able to accomplish this. Additionally, while many scientists are looking to the future for new ways to discover drugs, some are looking back, often with successful results. In the case of fungal penicillin, the ancient Egyptians knew certain molds had special healing properties. Meanwhile, in the mid 20th century, Tu You You, a Chinese scientist, utilized knowledge of traditional Chinese medicine dating back millennia to isolate a novel antimalarial compound from Artemisinin that saved millions. She went on to win a Nobel prize for her research.
The field of drug discovery is a fascinating one. If you want to participate, careers to consider are pharmacy and biochemistry. https://www.ncbi.nlm.nih.gov/pubmed/23985301 to learn more!
Listed below are some helpful links where you can go more in-depth with drug discovery!
https://www.nature.com/articles/s41573-019-0024-5 (applying machine learning to drug discovery)
https://medium.com/atomwise/machine-learning-for-drug-discovery-in-a-nutshell-part-i-24ae3f65c135 (applying machine learning to drug discovery)
https://towardsdatascience.com/how-is-machine-learning-revolutionizing-drug-discovery-25bfc8c0f0dc (applying machine learning to drug discovery) https://deepsense.ai/machine-learning-in-drug-discovery/ (applying machine learning to drug discovery)
by Andrew Gao
the helyx initiative 2020
bioinformatics education for all