Eli5: how do extended release drugs work?


Eli5: how do extended release drugs work?

In: 4

Not a doctor, obviously…

I was always under the impression that “extended release” drugs brake down further in the digestive system. Where as “instant release” meant the drug was first broke down in the stomach, THEN metabolize further by the rest of the digestive system. 🤷🏽‍♂️

They have an M&M like outside coating on part of the drugs which takes time to digest before you start to digest the chocolate on the inside.

The active ingredient is is mixed with inactive ingredients that slowly dissolve and release more of the drug into your system. Some drugs are best when they dissolve as quickly as possible to kick in, while others it’s better to have a slow, gradual release. How the active ingredient is packaged — pill, capsule, liquigel, etc and the specifics of the binders used all affect how long it takes for medication to dissolve and be absorbed.

I’m going to use a couple different candy-based analogies to explain some common dissolution systems.

The basic all-at-once-release way that most pills work is a bit like an M&M or a Tootsie Pop where you have to get through one sugary shell to get to all of the chocolate inside. In the drug-delivery case the inside would be medicine instead of chocolate, and the outside might be sugar or gelatin or something else entirely. The pill maker could also choose if they want a thin shell so that it melts quickly right in your mouth, or something thicker so that it melts later in your stomach or intestine; the choice of shell material can also make a difference as gelatin and sugar will take different amounts of time to dissolve.

One common extended-release method works like a [gobstopper](https://en.wikipedia.org/wiki/Gobstopper) which has layers of different flavors. (Or if you want to relate it back to that first analogy, you could imagine an M&M coated M&M coated M&M coated M&M…) In the drug-delivery case though it isn’t flavors that we are switching between, but rather medicine layers and non-medicine shells. In this way the pill can release some medicine as the first medicine-layer dissolves, and then it will take some time for the non-medicine shell below that to dissolve, but when that’s gone that next medicine layer can start to dissolve, and on and on. And once again, the pill-maker can change the thicknesses of each shell so that the time between medicine layers happens slower/faster.

Another extended-release method would be more like a Crunch Bar where tiny crispy rice pieces are trapped in a solid chunk of chocolate. In the drug-delivery case it’d be medicine instead of the crispy bits, and you get more medicine spread-out over time in the same way that some crispy pieces stay crispy until you’ve finally melted away the chocolate right around them.

The above two methods can also be combined in a number of ways (think Crunch-bar M&Ms, or Crunch-bar-layers in a multi-shell M&Mobstopper.)

There are also other methods in which fast-medicines and slow-medicines can be combined, among lots of other possible ideas, but the above couple examples are the most basic common kinds.