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In terms of stability, particle size has a direct effect on the ease of maintenance of a uniform suspended phase. Reducing the size of suspended drug particles therefore reduces the rate and likelihood of sedimentation, helping to maintain the dispersion.
Why is particle size important for suspension?
When a suspension is very well dispersed (i.e., deflocculated), the particles will settle as small individual particles. Particle size of the active agent plays a key role in the physical stability and bioavailability of the drug product. The rate of sedimentation, agglomeration, is affected by particle size.
Why rheology is important for suspension stability?
Rheologic consideration is of great importance in the study of the stability of pharmaceutical suspensions. This is because the viscosity of a suspension can modify the sedimentation rate.
What is the particle size of a suspension?
Difference between Colloid and Suspension Suspension Colloid Particle size greater than 1000 nm Particle size range from 1 and 1000 nm Particles settle down well Particles do not separate Can be separated by filtration Cannot be separated by filtration May scatter light Shows Tyndall effect (scatters light).
What is the importance of particle size for drugs of low solubility?
When the particle size is decreased, the larger surface area of the drug allows the increase in the surface area to volume ratio thus increasing the surface area available for solvation. Particle size reduction technologies are therefore routinely used to increase the bioavailability of poorly soluble drugs [2].
What will be the particle size after micronization of drugs?
When a drug is said to be micronized, that means its particle size is generally less than 50 microns. When an API is micronized, its particle size is about 4 to 10 times smaller than conventional drug particles.What is Micronization? Bacteria 0.2 to 3 microns Fine beach sand 100-250 microns.
How did you identify solution and suspension?
A solution is always transparent, light passes through with no scattering from solute particles which are molecule in size. The solution is homogeneous and does not settle out. A solution cannot be filtered but can be separated using the process of distillation. A suspension is cloudy and heterogeneous.
Why is suspension 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 the particle size of suspension Class 9?
Suspensions are heterogeneous mixture of two or more substances. Particles of solute do not dissolve in solvent rather they remain suspended in bulk throughout. The size of particles of suspension is large enough to be visible from naked eyes. They are greater than 1 nanometre (10−9 metre).
Which agent is used for stability of suspension?
Xanthan gum in drug delivery applications XG is widely used as a suspending agent and stabilizer in suspension due to its safety properties in food and drug applications. Moreover, it is soluble in water and can provide sufficient viscosity in low concentration.
What are 3 types of suspension?
There are three basic types of suspension components: linkages, springs, and shock absorbers.
What are the properties of solution and suspension?
Difference between Suspension, Colloids and Solution Property Suspension Solution Visibility Dispersed particles are visible by naked eyes Dispersed phase particles are not visible by naked eyes Stability Unstable Stable Examples Flour and water mixture Sugar and water solution.
How does particle size affect drug stability?
A product with a smaller, more uniform particle size is more stable and less likely to separate out. This translates to a longer shelf life and less waste.
What are the qualities of good 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 Dec 8, 2015
What is the stability of a suspension?
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.
Which is more stable Fe2+ or Fe3+?
Fe3+ is more stable than Fe2+. In Fe3+ ions, there are five 3d half-filled orbitals and is more symmetrical than Fe2+. Whereas in Fe2+ ion there are four 3d half-filled orbitals and one orbital is filled.
What technique can be used to distinguish between a suspension and a colloid?
The particles in a suspension may be separated by filtration unlike those in a colloid. Colloids are able to scatter light, but suspensions cannot transmit light. Particles in a suspension can be seen by the naked eye, but those in a colloid must be viewed using a light microscope.
How do you increase suspension stability?
There are some useful methods to improve the physical stability of a suspension, such as decreasing the salt concentration, addition of additives to regulate the osmolarity, as well as changes in excipient concentrations, unit operations in the process, origin and synthesis of the drug substance, polymorphic behavior
How particle size affect the characteristics of suspension?
Effect of Volume Fraction If there is no change in volume fraction, then reduction in particle size results in an increase in the number of particles present. This results in a higher effective volume fraction for a given particle loading, thus increasing the viscosity of the suspension.
Which is the correct order of stability of solution?
I > IV > II > III.
Is suspension can improve the chemical stability of a drug?
Suspension can improve chemical stability of certain drug. ➢Drug in suspension exhibits higher rate of bioavailability than other dosage forms.
Is a true solution stable?
True solutions are more stable than suspension. True solutions remain stable as the particles are almost uniform in size and do not settle down if left untouched for a given time interval.
How is suspension stability measured?
In a laboratory situation, suspension stability is measured by dispersing a protein powder in ambient temperature water (10% w/w) and pouring the aqueous protein dispersion into a 100 ml graduated cylinder.
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.
Does size Reduction improve physical stability?
Particle size reduction increases the surface energy which requires adequate stabilization by excipients. Altogether the study showed that excellent wetting of drug particles as well as their electrostatic and steric stabilization by excipients is necessary to produce stable nanosuspensions by nanogrinding.
What are the stability problems of suspension?
Because suspensions are thermodynamically unstable system, physical stability of suspensions becomes as important as the chemical and biological stability. Physical stability of suspensions is the condition in which the particles do not aggregate and in which they remain uniformly distributed throughout the dispersion.
