Flocculated Systems

Flocculated Systems

In this system, the disperse phase is in the form of large fluffy agglomerates, where individual particles are weakly bonded with each other. As the size of the sedimenting unit is increased, flocculation results in rapid rate of sedimentation. The rate of sedimentation is dependent on the size of the flocs and porosity. Floc formation of particles decreases the surface free energy between the particles and liquid medium thus acquiring
thermodynamic stability.

The structure of flocs is maintained
in sediment so they contain small amount of liquid entrapped within the flocs. The entrapment of liquid within the flocs increases the sedimentation volume and the sediment is easily redispersed by small amount of agitation.

Formulation of flocculated suspension system:

There are two important steps to formulate flocculated suspension

·  The wetting of particles

·  Controlled flocculation

The primary step in formulation is
that adequate wetting of particles is ensured. Suitable amount of wetting agents solve this problem which is described under wetting agents.

Careful control of flocculation is
required to ensure that the product is easy to administer. Such control is usually is achieved by using optimum concentration of electrolytes, surface-active agents or polymers. Change in these concentrations may change suspension from flocculated to deflocculated state.