Table of Contents
The main problem dealt with in this article is preventing the aggregation of particles in a suspension — extensive aggregation can lead to ‘caking’. This is the process in which almost all particles in the sediment become interconnected, making it impossible to resuspend.
How do I stop my suspension from caking?
Caking may be prevented by designing suspensions with a structured network that supports the particles and keeps them from entering a close-packed array. The network may consist of suspending agent (structured vehicle), the particles themselves (flocculated), or a combination of the two.
What is flocculation and caking?
The phenomena of caking and of flocculation in a sulfamerazine suspension system have been reported in the literature. Caking of the sulfamerazine suspension system is seen when the particles settle to a dense sediment before bonds can be established between the closely-packed particles.
Why is flocculation important?
Used water can contain significant amounts of suspended particulate matter, which often takes long to sediment. Flocculation expedites sedimentation and ensures efficient solid/liquid separation.
What are the classification of suspending agent?
Suspending agent consist of 3 types which is natural agent, inorganic salt and synthetic compound. Each types of suspending agents have their own function and examples. Every type of suspending agent should have suitable pH to maintain their viscosity.
How do I stabilize my suspension?
Stabilizing a suspension There are various routes that can be undertaken to improve suspension stability – for example, stabilization can be achieved by: preventing coagulation through inter-particle repulsion. slowing down sedimentation by increasing the viscosity of the continuous phase.
Why is wetting agent added in suspension?
Most organic drugs form particles with a hydrophobic surface and are difficult to disperse in an aqueous medium. Wetting agents are surfactants that reduce the surface tension of an aqueous medium, coat the surface of suspension particles, and thereby facilitate the wetting of each particle.
What is the major stability problem related to the suspension?
The main problem dealt with in this article is preventing the aggregation of particles in a suspension — extensive aggregation can lead to ‘caking’. This is the process in which almost all particles in the sediment become interconnected, making it impossible to resuspend.
Which suspension is more stable and why?
Suspension is more stable. This is because suspension does not mix with each other. The denser particles settle down at the bottom and makes the solution stable.
Why are suspensions unstable?
All suspensions, including coarse emulsions, are inherently thermodynamically unstable. They will, through random motion of the particles over time, aggregate because of the natural and dominant tendency to decrease the large specific surface area and excess surface energy.
What is an example of flocculation?
Flocculation and coagulation treatment chemicals are used in effluent wastewater water treatment processes for solids removal, water clarification, lime softening, sludge thickening, and solids dewatering. Examples of ChemTreat coagulation products include aluminum salts, iron salts, and polyelectrolytes.
What is the meaning of suspending?
transitive verb. 1 : to debar temporarily especially from a privilege, office, or function suspend a student from school. 2a : to cause to stop temporarily suspend bus service. b : to set aside or make temporarily inoperative suspend the rules. 3 : to defer to a later time on specified conditions suspend sentence.
What are 5 examples of suspension?
Examples of Suspension
- Muddy water.
- Milk of magnesia.
- Sand particles suspended in water.
- Flour in water.
- Slaked lime for whitewashing.
- Paints in which dyes are suspended in turpentine oil.
How do you evaluate suspension stability?
Suspension stability can be theoretically estimated prior to the beginning of the formulating process based on the solid phase particle size, liquid phase density, and viscosity. Stokes equation can be used to predict suspension stability in order to save time and resources.
Why do Flocculated particles not cake?
Repulsive forces between particles are overcome and a hard cake is formed which is difficult, if not impossible, to redisperse. The sediment is loosely packed and possesses a scaffold-like structure (large volume of final sediment). Particles do not bond tightly to each other and a hard, dense cake does not form.
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.
What is a suspending agent?
: 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.
Which suspension shows Claying effect?
In deflocculated suspension, individual particles are settling, so rate of sedimentation is slow which prevents entrapping of liquid medium which makes it difficult to re-disperse by agitation. This phenomenon also called ‘cracking’ or ‘claying’.
Which suspension is not pleasing in appearance?
INTRODUCTION
| Flocculated suspension | Deflocculated suspension |
|---|---|
| The supernatant is clear. | The supernatant is hazy. |
| Floccules stick to the sides of the bottle. | Particles do not stick to the sides of the bottle. |
| The suspension is not pleasing in appearance. | The suspension is pleasing in appearance. |
What can be used as a flocculant?
The following natural products are used as flocculants:
- Chitosan.
- Isinglass.
- Moringa oleifera seeds (Horseradish Tree)
- Gelatin.
- Strychnos potatorum seeds (Nirmali nut tree)
- Guar gum.
- Alginates (brown seaweed extracts)
Why suspension is formulated?
Suspension can improve chemical stability of certain drug. For example Procaine penicillin G. Drug in suspension exhibits higher rate of bioavailability than other dosage forms.
How do you make flocculated suspension?
Preparation of various types suspensions and determination of their sedimentation parameters
- Electrolyte and ionic surfactant can be used as flocculating agents to produce a flocculated suspension.
- The physical stability of the suspension is assist by determining the sedimentation volume or degree of flocculation.
What is the size of the suspended drug having the range of?
Pharmaceutical suspension may be defined as coarse dispersions in which insoluble solids are suspended in a liquid medium. Insoluble solids may have a size range from 10 to 1000 µm.
What causes flocculation?
In dispersed clay slurries, flocculation occurs after mechanical agitation ceases and the dispersed clay platelets spontaneously form flocs because of attractions between negative face charges and positive edge charges.
What chemical is used for flocculation?
Aluminum sulfate or alum (Al2(SO4)3), ferric chloride (FeCl3) and ferric sulfate (Fe(SO4)3) are the most widely used flocculants [1, 70]. These flocculants have a long history of use in removing colloidal particles from water and wastewater [15, 17].
