How do Scientists make drugs? A look into the Drug Discovery process

We’ve all had oral medication sometime in the past as a result of catching a cold or some other irritable condition. Maybe you’re popping some pills right now while reading this blog post. But, have you ever wondered where these pills come from? What do scientist’s actually do to create these therapeutic drugs?



  A familiar scene when a virus has struck. Image Credit: Library and Archives Canada, PA-025025. [CC BY 2.0]. Via Flickr

Step 1: Identifying Molecular Mechanisms


 Exploring the world on a microscopic scale. Image Credit: Enzymlogic. [CC BY-SA 2.0]. Via: Flickr


Viruses and diseases have been plaguing humankind throughout the ages. From the Plague of Athens in 430BC to the recent Ebola outbreak in West Africa, we seem to be locked in a constant battle with disease. Before any drug can be developed to address a particular condition, extensive work has to be carried out in identifying the root cause behind the condition. Advancements in molecular biology and biochemistry over the past decade have helped scientists gain a much better understanding of the molecular processes that occur during an infection.

For example, a particular virus might replicate itself by attaching to host cells via a particular protein (for more on viral replication click here). Once this particular protein has been identified, scientist’s can then work out how binding works on a molecular level. Drugs can then be formulated to disrupt this particular binding process thus inhibiting the virus from replicating. This is the guiding principle  behind much of anti-viral drug research.

Step 2: The Hard Work Begins: Designing a drug that actually works

Marshall_Nirenberg_performing_experiment (1)Time for some testing! Image Credit:MacVicar, N. – National Institutes of Health [Public domain] via Wikimedia Commons

Once specific molecular pathways have been identified, researchers then begin to work on drug formulation and design. Discovering and designing a drug that would actually interfere with target molecular pathways is a long process of trial and error. According to Novartis, only an average of 1 in 10,000 compounds tested would actually make it to the mass market, and early phase research typically takes up to 5 years before an appropriate compound is discovered. After discovery of an appropriate compound, it is then sent for clinical trials to be tested on humans.

Step 3: Clinical Trials.Is the drug safe for human consumption?



                                          Can I eat that? Image Credit: FtWashGuy. [CC BY-SA 3.0]. via Wikimedia Commons. 

Once a suitable compound has been discovered, it has to be subjected to rigorous testing under the Clinical Trials process. The trial typically consists of 3 phases and each phase is targeted at evaluating drug safety and efficacy. The 3 main phases are:

  • Phase 1: 10 – 20 Healthy Volunteers

The drug is tested on a small pool of healthy individuals to test for drug toxicity and excretion from the body.

  • Phase 2: About 200 Patients with the Disease

The drug is then administered to a select group of patients with the disease. Drug toxicity, efficacy, and any potential side effects are monitored as these may be different in patients as compared to healthy individuals.

  • Phase 3: 1000 or more Patients with the Disease

Phase III trials evaluate the drug to see if it works significantly better as compared to pre-existing treatments. In addition, further data on drug toxicity and efficacy are collected. Phase III trials are so rigorous that from 1949-2003, only 89 new molecules were approved by the FDA for use in treatments in America. Failure at Phase III is pretty common and costs companies billions of dollars each year.

Every country in the world has its own drug regulatory body and what is approved in one country might be rejected in another. An example is Nedaplatin which was approved only in Japan, and Lobaplatin in China.

For more information on Drug Discovery and Clinical Trials, check out the following links:

Novartis Loses Gilvec Patent Battle in India

Novartis Videos

Clinical Trials Database

Australia Pharmaceutical Patents Review Report 2013




4 Responses to “How do Scientists make drugs? A look into the Drug Discovery process”

  1. angwj says:

    Yea the process is long but necessary. There are even Phase 4 trials which are conducted after the drug has obtained approval to obtain more extensive data. What does ADR mean by the way? 🙂

  2. angwj says:

    Hi Oselan! Great questions! If volunteers suffer injury as a direct result of the clinical trial, they will be able to receive compensation from the sponsoring companies/organisations. Check out these few links:

    Medicines Australia Compensation Guideline
    Medicines Australia Clinical trials QnA
    Bristol-Myers Squibb halt Hepatitis C drug development after patient death. No causal link yet proven.
    BMS Press release 1
    Press Release 2

    With regards to animal testing, it is usually required as part of a clinical trials application process. Even if no side effects emerge during animal testing, there are many complex differences between the biology of humans and animals. Animal testing is thus not fool-proof and unexpected side-effects might emerge in humans. Phase I trials administer small doses of the drug to human volunteers to test for toxicity. That way, even if an adverse side-effect emerges, the severity will be reduced due to the small dosage.
    Check out this link! Alzheimers Europe Clinical Trials

    In some extreme cases, such as the recent ebola outbreak, drugs will be administered to patients without having gone through a lengthy cliincal trials process.

    All drug testing is conducted within an extensive legal and regulatory framework and the legal cost for getting a drug to Phase I can cost as much as $400,000 USD.

    Hope this Helps!

  3. georginao says:

    I can’t quite believe how long this process actually takes!! I’m lucky enough to work on clinical trials and get to see some of the final stages of how the drug will work which is exciting. But from there, I imagine its another year + before it gets on the market? (if successful and low ADR). How do we ever get anything done in science! 🙂

  4. oselan says:

    Such a new knowledge for me even though I consume drugs from time to time. Just wonder what happen if volunteers had problems by consuming new trial drugs as you mention in step 3 phase 1. I know some drugs need to be tested in animals first before applied to humans or is there any classification what kind of drugs that needs to test in animals and which type is not?