Question: How do the crystals help medicines go into our bloodstream better?

Lynne Thomas answered on 18 Jun 2014:

If you think about this you already know something about the answer. How would you prefer to take your medicines? For me, I definitely prefer to take a tablet and I’d avoid having to have an injection at all costs. Can you imagine having to have an injection every time you needed to take something for a headache? It turns out that the cheapest and easiest way to give people a medicine is to make a tablet. Tablets are solids and that also makes them crystals! Generally lots of crystals that we press together into a tablet.

When people discover new drug molecules, usually they first test whether it works in a test tube. But this is quite different to your body as your body is a complicated mixture of things. Your blood goes to every part of your body so if you can get the tablet to dissolve in your blood then you have a way of getting it to the right part of the body. Different things dissolve in different liquids to different amounts however. You take a tablet and then it goes into your stomach and stays there for a bit of time. If the medicine is going to be effective, it has to dissolve well when it is there and get through into your blood. So its really important to think about how well it is going to do this and a lack of dissolving in your blood is one of the main reasons that drug molecules don’t make it. This is called formulation.

It turns out that there isn’t just one way that a drug molecule can be put into a solid. Imagine that you are tiling your driveway with bricks. You can put them all parallel much like a brick wall or you can tilt them and make a prettier herring-bone pattern. Both use the same size and shape brick and fill the driveway but their arrangement is different. The same happens in solids but in three-dimensions and this is called polymorphism. It affects lots of ways that the solid behaves including how soluble it is but also things like what temperature it melts at.

If we can make the molecules change the way they join together in the solid, then we can make something more soluble and make it into something that would work when you took it! I hope that helps answer your question 🙂