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).
Purpose: To identify the mystery powder based on its physical and chemical properties, comparing them to the five substances and which one matches. The chemical reactions with water, universal indicator, vinegar and Iodine solution are then analyzed and matched with each other to determine the mystery powder.
• 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.
Size and stability: Liquid formulation can be bulky, difficult to transport and store.1 During storage under the stated conditions, it’s necessary that oral solutions are not subject to precipitation, fast sedimentation, caking or formation of lump.2 They have poor stability compare to solid dosage form formulation due to hydrolysis.1 Therefore, it’s important to optimize the active ingredient stability in liquid formulation including those prepared from powder or granules.2
- Fluidized-bed equipment can, however, be used to mix powders prior to granulation in the same bowl.
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.
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.
Yu A, St, Ish N. A study of the packing of particles with a mixture size distribution. Powder technology. 1993; 76 (2): 113--124.
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
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.
As the pressure drop increases in the column, it is observed that the degree of foaming becomes more violent and more spread out. When the pressure drop is relatively high, it means that the pressure exerted by the vapour is insufficient to hold up the liquid in the tray, causing the gas bubbles to appear on top of the sieve trays. To add on, the higher the pressure drop, the higher the velocity of the vapour passing up the column. As a result, more vapour will penetrate the liquid and more bubbles formation is observed. Due to more bubbles formation, the degree of foaming are more agitated, rapid and spread out.
Furthermore, dust control measures such as road watering at the Administration area for example suppress dust, which reflects in lower dust levels
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.
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:-
Emulsion is a mixture of two liquids that is not naturally mix together which one of the liquids being dispersed as small spherical droplets. There are two types of emulsion which is oil-in-water and water-in-oil. Oil-in-water emulsion is the dispersed oil droplets in an aqueous phase of a system. For example, milk dressing and mayonnaise. In contrast, water-in-oil emulsion is the dispersed of water droplet in an oil phase of a system. For example, margarine and butter. The substance that makeup the droplets referred as dispersed phase while that makeup surrounding liquid is called continuous phase. The process of converting two separate immiscible liquids into emulsion is known as homogenization. Temporary emulsification is created. Since oil and water is immiscible, the oil droplets will realign themselves as predicted by Stokes’ Law and recreate surface tension. This is because the difference surface tension makes them immiscible with one another.