A pharmaceutical suspension may be defined as

The physical chemist defines the word "suspension" as
One-phase system consisting of an undissloved or immiscible material dispersed in a vehicle (solid, liquid, or gas).

Generally pharmaceutical suspensions containe

The suspensions have dispersed particles above the colloidal size that is mean particle diameter below1um.

Examples of Pharmaceutical Suspensions oral suspension dry powder is

Insoluble drug or poorly soluble drugs which required to be given orally in solid dosage forms ( in case of children, elderly, and patients have difficulty in swallowing liquid dosage forms)

Insoluble derivative formulated as suspension An example

Some materials are needed to be present as finely divided forms to increase the surface area. Fore example,

Application suspention in vaccines such as

X-ray contrast media: an example is oral and rectal administration of propyliodone