What does a suspension refer to in pharmacology?

In pharmacology, a suspension refers to a type of medication formulation where the active drug particles are not fully dissolved in the liquid. Instead, they remain dispersed throughout the solution, resulting in a heterogeneous mixture. This means that if left standing, the solid particles can settle at the bottom, requiring the mixture to be shaken or agitated before administration to ensure an even distribution of the drug.

This characteristic of suspensions distinguishes them from solutions, where the solute is completely dissolved in the solvent. While suspensions can be effective for delivering medications, they require careful handling and formulation to ensure that the correct dose is delivered to the patient consistently. The other options describe different types of formulations or drug interactions but do not align with the definition of a suspension in pharmacology.