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There are suspensions that can be either flocculated or deflocculated. The main difference between flocculated and deflocculated suspension is that the rate of sedimentation in a flocculated suspension is rapid whereas the rate of sedimentation in a deflocculated suspension is slow.
Which is more stable Flocculated or Deflocculated?
Most stable pharmaceutical suspensions are flocculated. 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.
Which type of suspension have relatively greater bioavailability?
h/mL) were significantly greater compared with fasting (p < 0.0001). Conclusions: This study has shown that the new atovaquone oral suspension also has significantly greater bioavailability when administered after food or a nutrition supplement that has a moderate fat content.
What are the disadvantages of Unflocculated system?
However, a major disadvantage of this technique are the operational costs. In some cases, considerable quantities of coagulant and flocculant are needed to achieve the required level of flocculation. A certain quantity of physico-chemical sludge is also formed, which is normally processed externally.
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 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.
Is a suspension stable?
Suspension Stability Increasing the zero-shear viscosity of the continuous phase of an emulsion or suspension is a popular method of increasing physical stability. Controlled stress measurements on high performance rheometers are a necessity for zero-shear viscosity testing.
What increases drug bioavailability?
The main mechanisms that have been identified through which bioenhancers can improve the bioavailability of drug molecules include alteration of the plasma membrane fluidity to increase passive transcellular drug permeation; modulation of tight junctions to allow for increased paracellular diffusion; and active efflux Jan 16, 2019
What is needed for good bioavailability?
The most reliable measure of a drug’s bioavailability is AUC. AUC is directly proportional to the total amount of unchanged drug that reaches systemic circulation. Drug products may be considered bioequivalent in extent and rate of absorption if their plasma concentration curves are essentially superimposable.
Why is oral bioavailability low?
Low bioavailability is most common with oral dosage forms of poorly water-soluble, slowly absorbed drugs. Insufficient time for absorption in the gastrointestinal (GI) tract is a common cause of low bioavailability.
Is Redisperse difficult?
The repulsive forces between individual particles allow them to slip past each other as they sediment. The slow rate of settling prevents the entrapment of liquid within the sediment, which thus becomes compacted and can be very difficult to redisperse.
Why is flocculation necessary for suspension?
Why is flocculation necessary for suspension? The principal use of flocculating agents is to aid in making solid–liquid separations. Removing small amounts of suspended inorganic or organic particles from surface water prior to its use as drinking water or industrial process water.
How can we avoid floc shearing?
To prevent floc from tearing apart or shearing, the mixing velocity and energy are usually tapered off as the size of floc increases. Once flocs are torn apart, it is difficult to get them to reform to their optimum size and strength.
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 flocculating suspension?
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.
Which cation is most stable?
(CH3)3C+3∘ carbonium ion is most stable.
Which form of drug has highest bioavailability?
Thus having the highest bioavailability. Tablets take time to disintegrate. The order of decreasing bioavailability will be, solutions > emulsions > suspensions > capsules > tablets > coated tablets > enteric coated tablets>sustained released products. 4.
How can you prevent suspension from sedimentation?
Slow down sedimentation by increasing viscosity of continuous phase. Velocity increases with the square of particle size making this the most critical parameter. For concentrated systems a crowding factor must be introduced which incorporates the phase volume Φ.
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. |
How can flocculation be prevented?
When particles of a suspension come close together they can form aggregates called flocculates which will settle more rapidly. To prevent that we often coat the particle with a charged surfactant. The charge (Zeta potential) acts to keep the particles separate and prevent flocculation.
What are the advantages of suspension?
Advantages of suspensions dosage form
- 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.
How Deflocculation is different from flocculation?
The key difference between flocculation and deflocculation is that flocculation is the formation of flocs by the clumping of fine particles, whereas deflocculation is the dispersion of flocs to form a stable colloid. Flocculation refers to the formation of clumps from fine particles in a colloid.
What is 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.
What does Flocculated mean?
The process by which individual particles of clay aggregate into clotlike masses or precipitate into small lumps. Flocculation occurs as a result of a chemical reaction between the clay particles and another substance, usually salt water.
How do I know if my suspension is stable?
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.
