What is the term for a medication that is designed to dissolve at a slow rate?

In the context of medications, the term "spansule" refers specifically to a formulation designed to release its active ingredients gradually over time. Spansule capsules typically contain small beads that dissolve at different rates, allowing for a sustained release of medication. This mechanism ensures that the drug remains effective over a longer period, minimizing the number of doses a patient needs to take throughout the day.

Extended-release and time-release formulations also aim to achieve a similar effect of prolonged action but are broader categories that can include various methods of achieving sustained release. Delay-release isn’t a standard term used for this type of formulation. Therefore, the specific designation of spansule is the most accurate choice when describing a medication designed to dissolve at a slow rate.