Suspension:-
Suspension is a biphasic liquid dosage form composed of finely divided insoluble solid particles dispersed in a liquid medium.
The size of suspended particles ranges from 0.5 micron to 5 micron.
Solid particles act as dispersed phase.
Liquid vehicles act continous phase .
Suspensions are usually used in orally, parentally and also externally.
Method of preparation:-
(1) Suspension are prepared by grinding the insoluble material in the mortar to a smooth paste with a vehicle containing the wetting agent.
(2) All soluble ingriedient are dissolved in same portion of the vehicle and added to the smooth paste to get slurry.
(3) The slurry is transformed to a graduated cylinder, the mortar is rinsed with successive portion of the vehicle.
(4) Decide whether the solids are
--> suspended in a structured vehicle
--> flocculated
--> flocculated and then suspended
Add the vehicle containing the suspending agent or flocculating agent.
(5) Make up the dispersion to the final volume, thus suspension is prepared.
Differences between deflocculated and flocculated suspensions:-
