According to examples, an apparatus may include a memory on which is stored instructions that may cause a processor to receive an intended release profile for a drug, the intended release profile including a certain release rate of the drug over time following ingestion of the drug. The instructions may also cause the processor to determine a group of release modules that contain the drug, the determined group of release modules having release profiles for the drug that together meet or approximate the intended release profile for delivery of the drug, and at least two of the release modules in the group having different release profiles for the with respect to each other.
