Dissolving Pills Aren’t Just Beautiful. They’re Science as Hell
Pills get into your bloodstream by dissolving in your stomach. But the point of your stomach is to quickly dissolve things, so drug companies have a problem if they want to give you something that releases over the course of the day instead of in a single burst. One solution? Make a pill crisscrossed with a spongy network of holes—like some of the ones that dissolve in technicolor in this awesome video.
At first glance, it seems like poking holes in a pill would have the opposite effect. A spongy pill has much more surface area touching water than a solid one does: It should dissolve faster, not slower. (Incidentally, this is roughly why your brain and intestines are both folded instead of smooth—more points of contact mean more efficient work, whether it’s sending neural messages or digesting food.)
The world is subtler than that, though. Sure, initially the water penetrates into the network and quickly dissolves a lot of the pill—more than it would have without the holes. But a lot of the dissolved stuff isn’t swept away. It just sits around the tablet, forming a kind of barrier that prevents more water getting in and dissolving the rest.
You can’t just keep dissolving stuff in water forever. Eventually, the water becomes saturated; it hits a point where any more of the stuff can’t dissolve. This is what happens after the first stage of the tablet’s dissolution: A cloud of saturated water surrounds the tablet, preventing any more dissolving until the cloud is swept away into your bloodstream. When that happens, saturated water within that network of spongy holes migrates to the edge of the pill, ensuring that the same amount of the drug is released throughout the day.
Of course, the reality in your body is far more complicated. Stomachs are dynamic and filled with hydrochloric acid, pills have a huge range of methods to prolong their release, and this is a very simple picture of dissolution. But these simple yet stunning videos provide at least some insight into how companies use simple diffusion physics to keep patients from having an eye on their watches all day.
Read this article: