1.3 Granulation
Granulation is a common technique used to produce powders that can be compacted. In this process, the particles are enlarged via agglomeration of the particles while still maintaining the original particles integrity.
Granulation importance
• Granulation is important to prevent segregation of the particles in the powder. Segregation may be due to the different density or sizes of particles. Denser particles tend to settle at the bottom of the container while the lighter particles will tend to stay on the top.
• Granulation helps to improve the characteristics of the powder mix for compaction. Granules are often easy to compact and create stronger tablets.
• It decreases the chances for caking of partially hygroscopic materials, in case of storage as a powder. This is achieved since the moisture is adsorbed onto the surface of the granulated particles and they can still maintain their flowability due to its size(1).
There are 2 types of granulation: Wet granulation and dry granulation. As the name suggests, wet granulation requires a liquid to be used in the process of agglomeration whereas dry granulation doesn’t require any liquid. Both these processes will be discussed in detail in the upcoming sections.
1.3.1.1 Mechanism of particle agglomeration in wet Granulation
The granulation liquid (fluid) contains a solvent which must be volatile so that it can be removed by drying and be non-toxic. Typical liquids include water, ethanol and isopropanol either alone or in combination(2).The liquid solution can be either aqueous based or solvent based. Aqueous solutions have the advantage of being safer to deal with than solvents. Water also has disadvantages as a solvent since it can affect drug stability adversel...
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... than that required for making a tablet via direct compression.
• Due to the addition of water, entrapped air is decreased which reduces the dustiness as compared to dry granulation.
• Prevents the segregation of the components by forming a homogeneous powder.
• Dissolution rate of hydrophobic drugs is improved due to certain binders and solvents.
Disadvantages of wet granulation are:
• This method is expensive due to cost of time, equipment, energy and space requirements as compared to direct compression.
• Increased number of processing units increases the chance of problems such as difficulty in controlling or validation.
• Air and vapour handling equipment needs to be in place to get rid of vapour in case of solvent being a health hazard.
• Incompactibity between the components of formulation will be aggravated due to being in contact with the solvent(2).
By reducing the volume in which the same amount of particles exists the pressure is increased. Once the same number of particles is in a smaller area there is less space in which to move and so the particles are more likely to collide each other. Using a catalyst is another method I could use. A catalyst is a substance, which lowers the activation energy of a reaction without being chemically altered. Energy.
• Milling – The first step of the process is crushing the malt. This breaks apart the grains, exposing the starchy ball inside and making it accessible to the brewer. The grains are only lightly crushed, leaving the hulls intact to serve as a filter bed for the lautering process later on.
Processed milks are generally homogenized to further disperse the fat globules in the milk. This gives the milk its smooth and uniform texture. It also prevents the rising of cream to the top. After homogenization, softer curds will be produced, and coagulation may no longer be observed.
- Fluidized-bed equipment can, however, be used to mix powders prior to granulation in the same bowl.
If the solid dissolved in the solvent at room temperature, then it was too soluble and that solvent could be eliminated. The acetanilide is completely dissolved in ethanol and dichloromethane, therefore eliminating them from being the suitable solvent. If the solid did not dissolve at room temperature then it was placed in the sand bath and left to boil. If the solid dissolved, it was placed in the ice bath and if crystals were observed coming out of the solution then the suitable solvent was found. The suitable solvent was water as the crystals came out once placed in the ice bath.
The water which is added into the 100 grams of soil has the highest aggregate water stability. The alfalfa has a higher nitrogen amount thus will exhibit a low C:N ratio. Thus the treatment in alfalfa will have limited excretion of extracellular polymers that can help bind the aggregate thus the stability of the aggregate for this treatment will be quite unfavorable as is seen in the table. The sucrose treatment will
It is mainly reduces the solids which are present n the suspensions or emulsions or the reduction the droplet size in the suspensions. It is almost used for the all types of materials for the reduction.
The positive skew, larger proportion of small particles, results in an increase of packing density. This is due to the small particles being able to fi...
Particle size analysis is a method or part of laboratory techniques of finding the size range and or the usual mean size of the particles in a residue or in a liquid substance.
Gravels constitute the majority of coarse aggregate used in concrete with crushed stone making up most of the remainder. Angular aggregate increase the void content. Larger sizes of well-graded aggregate and improved grading decrease the void content. Absorption and surface moisture of aggregate are measured when selecting aggregate because the internal structure of aggregate is made up of solid material and voids that may r not contain water. The amount of water in the concrete mixture must be adjusted to include the moisture conditions of the
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Furthermore, dust control measures such as road watering at the Administration area for example suppress dust, which reflects in lower dust levels
Emulsifiers are classified as stabilizer to stabilize emulsion. Common emulsifier that usually use is lecithin which can be found in egg yolk. Lecithin act as a surfactant that will decreasing or complete diminish the surface tension to form emulsification. Lecithin in the egg yolk is commonly the only emulsifier that added into the emulsion. However, the vegetable oil may contain emulsifiers that inhibit crystallization. Lecithin will facilitate agglomeration during spray drying. During spray drying process, the hydrophobic portion of emulsifier will dissolve in the cocoa butter, orienting the hydrophilic portion of the phospholipid toward the surface of particle. (Van Nieuwenenhuyzen,1981). This increased affinity of the cocoa powder for water aids dispersion and
The initial step in the transformation from a liquid to a solid phase in a supersaturated solution is called nucleation. This process begins with the combination of stone salts in solution into loose clusters that may increase in size by addition of new components or clusters (Boskey, 1981). There are two steps to form a crystal from supersaturated solution and these are:-
Crystalloids are typically based on a solution of germ-free water with added electrolytes to approximate the mineral content of human plasma. Crystalloids come in a variety of originations, from those that are hypotonic to plasma to those that have equal or unequal tensions. It was designed to approximate the mineral and electrolyte concentration of human plasma. Colloids are often based on crystalloid solutions, thus containing water and electrolytes, but have the added component of a colloidal substance that does not freely diffuse across a semipermeable membrane. They are widely used for clinical improvements such as lung injury and other bacterial peritonitis.