Here is your short essay on Pharmaceutical Suspension

A pharmaceutical suspension may be defined as a dispersion in which finely divided solid particles are suspended in a liquid medium.

Dispersed solid particles are known as internal phase and dispersion medium is known as continuous phase/external phase. Particles smaller than 0.1 to 0.2 are generally considered to be colloidal.

A solid in liquid dispersion in which the particles are above colloidal size (upto 1000 ^m) is termed as coarse suspension. In other words suspensions are heterogeneous (biphasic) system consisting of two phases. The continuous phase or external phase is generally a liquid or semisolid and the dispersed or internal phase is made up of particulate matter that is essentially insoluble in but dispersed throughout the continuous phase.

Ideal Suspension

I. The suspension must remain sufficiently homogeneous for at least the period between shaking the container and removing the required dose from the container.

II. The sediment produced on storage must be easily re-suspended by the use of moderate agitation/shaking.

III. The suspension may be required to thicken in order to reduce the rate of settling of particles but the viscosity must not be too high that is not suitable for removing the dose from container.

IV. The suspended particles should be small and uniformly sized in order to give a smooth, elegant product, free from a gritty texture.

V. The suspension should resist microbial attack during storage and also maintain during the shelf-life all organoleptic properties as initially.

VI. Topical suspension should spread easily when applied.