Formulation of suspensions:

During the preparation of physically stable pharmaceutical suspensions, a number of formulation components are employed to help keep the solid particles in a state of suspension, whereas other components are merely part of the liquid vehicle itself. These formulation components are classified as follows -

Components of the suspending system:
à Wetting agents
à Dispersant or deflocculation agents
à Flocculating agents
à Thickeners

Components of the suspending vehicle or external phase:
à pH control agents and buffers
à Osmotic agents
à Coloring agents, favors and fragrances
à Preservatives to control microbial growth
à Liquid vehicles