New Medicines — What It Takes for One Pill to Exist

A medicine is a key

The body holds tens of thousands of proteins, each shaped differently and doing different work. One passes on the signal we feel as pain; another is what a bacterium uses to build itself.

A medicine is a key that fits one of those proteins. Fitted, it blocks what the protein was doing, or urges it on. So finding a medicine means choosing the lock first and then hunting for the key.

Where the keys come from

Once they came from nature. People long knew that chewing willow bark brought a fever down, and later the molecule actually doing the work was isolated. Others came out of moulds.

Today nature and synthesis are used together. Tens of thousands of candidate molecules are held against the lock one by one; anything that fits even slightly is then reshaped, a little at a time, to fit better. That reshaping is the work of the chemistry institute in Daejeon.

Working and being safe are different

Here is where most people's picture stops short. Finding a key that fits the lock does not give you a medicine.

It must survive being swallowed, be absorbed, travel to the right place, not fall apart on the way, and leave the body once its work is done — without wrecking anything else en route.

So few candidates clear all of that: of thousands picked at the start, perhaps one becomes a medicine.

A little further in

How do you know what is harmful?

Nothing is harmless. Drink enough water and it will injure you. So the question is never whether a substance is harmful but from what amount.

And not only amount. A large dose at once differs from a small one over years; breathed in differs from swallowed. Hence the many separate kinds of test.

None of this is only for medicines. New chemicals, pesticides and the ingredients of household products pass the same way before reaching the world.

Long use is not proof

Herbal materials meet the same standard, and much of the work at the Korean medicine institute in Daejeon is exactly this: separating out what a material actually contains, and establishing what those components do.

That something has long been used is no proof that it works. Plenty of long-used things did nothing, and some did harm. But long use is no reason to dismiss it either — often enough a real working molecule was in there. Willow bark was.

So the work is not to take sides but to check: measure what is in it, test whether it does anything, find the amount at which it harms.

Why three separate places

The maker and the tester are kept apart for the same reason as in the reactor article: no one should pass their own work.

Medicine is taken by people who are ill and have no way of checking it themselves. This structure is the promise to check on their behalf.

What you would study to do this

The number of trainings behind one tablet is surprising.

1. Someone who actually builds the molecule — organic chemistry.
2. Someone who chooses which protein to aim at — biology and biotechnology.
3. Someone who follows what it does once inside the body — pharmacy and pharmacology.
4. Someone who tests from what dose it harms — toxicology and veterinary science.
5. Someone who separates a real effect from a coincidence — statistics.
6. Someone who turns a molecule into a tablet or an injection — formulation and chemical engineering.

You do not have to love chemistry to belong here. The field needs people good at statistics, people who work with animals, people who design factories. It is also why one medicine takes more than a decade: every one of these stages has to be passed in turn.

The question that remainsIf dose and not substance divides poison from medicine — what else that we have sorted into good and bad is really a question of amount?