Question: how do you test your medicines

Jean Bourke answered on 17 Nov 2012:

Oooh good question.

Medicines have to go through a lot of test before they make it to a pharmacy. We call these “clinical trials.”

When you make something, you have to first work out if it does what you think it does. You can apply it to some of the cells you want it to work on. Of course, even it doesn’t work, it may have other effects on other kinds of cells. You have to check other kinds of cells too. These test need to be repeated many times before you are sure your results are conclusive (need to replicate results).

Now we are onto the touchy subject of animal testing. Animal testing is essential, at least it currently is. That is not to say that anyone likes it or is happy about it. There are many many scientist and teams of scientists working on getting around having to test on animals.

The first thing you do is give tiny amounts of your medicine to only a few healthy mice. Usually it has no effect on them whatsoever. What you are trying to see is how the medicine is broken down in the body, how quickly to the levels in the blood increase, how quickly do they decrease, is it secreted in the urine, the sweat, the saliva, the poo? What is it broken down into?

This is where you start to give it to sick mice, again to only a few. You need to find out if it works in the body, not just in cells in the lab. You work out how much you need to give to have an effect, how much is bad, how often you need to take the medicine. This is where a lot of medicines fail.

Next you give to a few healthy people, just a tiny bit to see if it is safe for humans. You can’t give it to a person without having tried it on a mouse first because you need to reduce the likelihood of killing someone!

If it gets past this you move onto giving it to sick people. Just a few to see if it works in humans. You have to work out how to give your medicine: as a pill, as a drink, as an injection, as a cream. We call this the formulation. You also establish the does.

Next you move onto large scale clinical trials where you give it to load of sick people and make sure it works all the time, check for side effects, find out if it interacts with any other drugs etc. Again, a lot of drugs fail at this stage.

Clinical trials take year and years and cost many millions so companies want a drug to fail early, saving both animals, money and time.

I have only done some test with cells grown in the lab. My research is still a long way from proper clinical trials. At some point you need to do what we call a “scale up”. When you are just using a little bit of your medicine, it’s easy to keep making it the way you started off. As time goes on, and you make it through the different trials you need more and more of it so you need to find a way to make large quantities. Sometimes what works in the lab is not really practical on a large industrial scale. So while the biologist, pharmacist, and doctors are working away so are chemists!

I hope the gives you an idea of what everything in your local pharmacy has been through and how much work goes into everything.

Thanks for the question.