Solutions refer to the presence of dissolved substances in solvents, mostly water. We can have a dilute solution or a concentrated solution. These are comparative terms. A dilute solution can be a small amount of dissolved substance, and a concentrated solution contains a higher amount of dissolved substances. We can also have an unsaturated solution and a saturated solution. A saturated solution has the maximum amount of solute dissolved at a fixed temperature. But an unsaturated solution can have more solute dissolved at a given temperature.
A saturated solution becomes unsaturated at higher temperatures. Conversely, an unsaturated solution becomes saturated at a lower temperature. For medicinal formulations, only dilute solutions are used. Generally, drug formulations are prepared using water as a solvent. The Indian system of medicine also refers to the use of oil, ghee, milk, and other substances as solvents for drug formulations to achieve the beneficial strength of the drug. In some cases, some solvents are used to extract and isolate important compounds from plants. Asima Chatterjee was given the Shanti Swarup Bhatnagar Award for her work on the isolation of important medicinal compounds from plants.