Flocculation is
a process whereby small particles in suspension are caused to aggregate
, giving large clusters (flocs) that are much more easily separated than the original particles. The process is in widespread use in many industrial applications.
What is flocculated suspension in pharmacy?
Flocculated suspensions
Flocculation refers to
the formation of a loose aggregation of discrete particles held together in a network like structure by physical adsorption of macromolecules
when the longer-range van der Walls forces of attraction exceed the shorter-range forces of repulsion.
What are the features of flocculated suspension?
| Flocculated suspension Deflocculated suspension | The rate of sedimentation is high. The rate of sedimentation is slow. | Sediment is easy to re-disperse. Sediment is difficult to re-disperse. | Sediment is loosely packed and does not form a hard cake. Sediment is tightly packed and forms a hard cake. |
|---|
Is Redisperse difficult?
In a deflocculated system the dispersed particles remain as discrete units. Because the rate of sedimentation depends on the size of each unit, settling will be slow. … The
slow rate of settling
prevents the entrapment of liquid within the sediment, which thus becomes compacted and can be very difficult to redisperse.
How do you make flocculated suspension?
Electrolyte and ionic surfactant
can be used as flocculating agents to produce a flocculated suspension. suspension prepared without flocculating agent is a deflocculated one. The physical stability of the suspension is assist by determining the sedimentation volume or degree of flocculation.
What are the advantages of suspension?
- Suspensions are a useful drug delivery system for therapeutic agents that have a low solubility. …
- Pharmaceutical suspensions may be formulated to mask the unpleasant/ bitter taste of drug.
What is the difference between flocculated and non flocculated suspension?
The suspension are said to be flocculated ,when the individual particles are in contact with each other and form a network like structure . Whereas in case of non-flocculated suspensions,
the individual particles exists as a separate entity
. … In Non-flocculated suspensions The rate of sedimentation is slow.
What are the steps in preparing suspension?
- 1 Direct Incorporation/ Dispersion Method.
- 2 Precipitation method.
- 3 Controlled flocculation.
- 4 References.
What is the reason why we need to formulate suspension?
The reasons for the formulation of a pharmaceutical suspension:
— when the drug is insoluble in the delivery vehicle
. –To mask the bitter taste of the drug. –To increase drug stability.
What is particle size of coarse dispersion?
Colloids are dispersions of solid particles in a fluid. The particle size of the dispersed material is
between 1 nm and 0.1 micrometer
. This small size results in material which does not sediment under normal conditions.
What is coarse dispersion?
Coarse dispersions are
heterogeneous dispersed systems
, in which the dispersed phase particles are larger than 1000 nm (4*10
– 5
“). Coarse dispersions are characterized by relatively fast sedimentation of the dispersed phase caused by gravity or other forces.
Which is desirable suspension?
Desirable properties of suspensions are that
they should have good organoleptic properties
, suspensions should possess good pourability leading to ease of removal of dose from container, the particle size distribution should be uniform, there should be ease of re dispersion of settled solid particles, they should be …
What are the suspending agents?
: a substance (such as carrageenan, xanthan gum, or cellulose ether)
that is added to fluids to promote particle suspension or dispersion and reduce sedimentation
All these drinks can contain preservatives, and drinks other than juices can contain additives to colour, flavour and sweeten.
What are ingredients used in suspension?
- 1 1. Solvents/ Vehicle.
- 2 2. Co-solvent.
- 3 3. Buffering agents.
- 4 4. Preservatives.
- 5 5. Antioxidants.
- 6 6. Wetting agents/ surfactants.
- 7 7. Anti-foaming agents.
What are the disadvantages of suspension?
Suspensions also possess some disadvantages relative to other dosage forms. The primary disadvantage is
their physical instability
; i.e., that they tend to settle over time leading to a lack of uniformity of dose.
Why are some drugs suspended?
Substances can be chemically unstable, insoluble in water
, distasteful etc. Suspensions are often used as a dosage form when the drug is insoluble in water and when use of solubilizing agents is not possible.
