trituration

Question 1

intro

Answer 1

 It is also called as dry grinding.
 Trituration may be used both to comminute and to mix powders.
 By trituration the grinding of a solid substance is done to fine powder by continuous striking or rubbing
the particles in a mortar with a pestle.
 If simple admixture is required without special need for comminution, the glass mortar is usually
preferred.
 When a small amount of a potent substance is to be mixed with a large amount of diluent, geometric
dilution method is used to ensure the uniform distribution of the potent drug.
 This method is specially indicated when the potent and other ingredients are of the same color and a
visible sign of mixing is lacking. By this method the potent drug is placed on an approximately equal
volume of the diluent in the mortar and mixed thoroughly by trituration. Then a second portion of
diluent equal in volume to the mixture is added and the trituration repeated and so on. This process is
repeated until all the diluent is incorporated.

Question 2

trituration using tile and spatula

Answer 2

 Small quantities of finely powdered solids may be mixed on a tile by means of a spatula.
 Tiles are usually made of glass and should be large enough for the quantity of powder to be mixed or
ointment to be prepared.
 Usually for small scale work 300mm square is a useful size for a tile.
 Spatula is made of stainless steel except for the few medicaments those react with stainless steel
(iodine), should be flexible and long blade (25mm by200mm) to provide a large rubbing surface.
 Powders for Trituration are placed on the tile and gently mixed until the mixture is smooth and
homogeneous, but in the case of ointment if base is very soft it may be helpful to warm the tile but
overheating should be avoided because the base will become too fluid for efficient levigation and may
run off the edge of the tile. The dispersion is then diluted with increasing amount of base, doubling the
quantity each on the tile of each dilution. Finally, any liquid ingredient is incorporated.

Question 3

using mortar and pestle

Answer 3

 A mortar should be used when the quantities are too large to be conveniently dealt with tile.
 A mortar with a fairly flat base and a pestle with a flat head will give best results.
 It is impossible to ensure intimate dispersion of one powder in another by mixing the two substances
all at once. The purpose is to add a substance that is present in greater amount to the whole of the
substance present in lesser amount.
 Substance present in greater amount is introduced into the mixture in very small quantities at first, but
gradually increasing the quantities, until the whole of the substance has been added. In the case of
ointments, the sequence of mixing is same as in the tile method, powders are mixed and then gradually
incorporated into the base and finally any liquid ingredients are added.

Question 4

application

Answer 4

 A mortar should be used when the quantities are too large to be conveniently dealt with tile.
 A mortar with a fairly flat base and a pestle with a flat head will give best results.
 It is impossible to ensure intimate dispersion of one powder in another by mixing the two substances
all at once. The purpose is to add a substance that is present in greater amount to the whole of the
substance present in lesser amount.
 Substance present in greater amount is introduced into the mixture in very small quantities at first, but
gradually increasing the quantities, until the whole of the substance has been added. In the case of
ointments, the sequence of mixing is same as in the tile method, powders are mixed and then gradually
incorporated into the base and finally any liquid ingredients are added.