How do time-release pills work?
Time-release pills are designed to release a steady stream of a drug into your system over a certain period of time (six to eight hours) instead of an instant ‘hit’ of the drug in one go. This can be especially useful for continual suppression of unwanted symptoms of certain diseases or when painkillers need to be administered over a long length of time rather than the effects of the drug wearing off quickly. The active ingredient is usually concealed in a ‘web’ of insoluble substances, so that the dissolving substance has to find its way through the gaps in the web. Alternatively, the drug can be combined with other substances that, once ingested, swell up to form a gel with a near impenetrable outer coating, therefore releasing the active ingredient slowly. Some drugs will naturally dissolve slowly and therefore don’t need to be embedded in other less-soluble substances.
Author: Rik Sargent, Science Museum