SUPENSIONS - PHARMACEUTICS II (Dispensing Pharmacy) D. Pharm 2nd year PDF Notes



Suspensions are biphasic liquid dosage form consisting of finely divided solid particles dispersed in liquid medium with the help of suspending agent.


The requirements/charateristics for a good suspension

1.      It should be chemically stable.

2.      The sediment should be easily re-dispersed.

3.      The suspension should be easily removed from the container.

4.      The suspension should be free from large particles.

5.      They should be resistant to micro – organisms.

6.      Suspension for internal use must be palatable & suspension for external use should be force from gritty sealing.


Flocculated & De-flocculated suspension.


Flocculated suspension:

In flocculating system, when a suspending agent is added it should be well absorbed, due to the repulsive forces are low & the attractive forces are high. The individual particles are able to attract each other & form loose aggregates known as floccules. This suspension is said to be flocculated.


Deflocculated suspension:

In deflocculated system, when a suspending agent is added. The individual particles are dispersed with the aid of suspending agent. Due to the repulsive forces are high & the attractive forces are low. The individual particles are not able to attract each other. So the particles remain dispersed & do not aggregate. This suspension is said to be de-flocculated.

Differences between flocculated suspensions.

          Flocculated suspension

       Deflocculated suspension

1. Particles from loose aggregate

Particles exist in suspension as separate entity

2. Rate of sedimentation is high

Rate of sedimentation is low

3. Sediment is formed rapidly

Sediment is formed slowly

4. The floccules stick to the sides of the container

They do not stick to the sides of the container

5.On shaking the sediment is easily re-  dispersed

On shaking the sediment is difficult to re-disperse

6. The suspension has a pleasing appearance

The suspension does not have a pleasing appearance

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