Techniques that are used in pharmaceutical iundustries to prepare drugs and medicines like size separation and reduction, leaching, evaporation, and drying.

1. TECHNIQUES OF PHARMACEUTICAL INDUSTRIES
PRESENTED BY: ASHA PATEL
CLASS: M.Sc. MICROBIOLOGY

2. TECHNIQUES:
 Size separation
 Size reduction
 Leaching
 Evaporation
 Drying

3. SIZE REDUCTION
 Size reduction is the operation carried out for
reducing the size of bigger particles into smaller
one of desired size and shape with the help of
external forces.
 Comminution, Grinding, Milling pulverizing or
crushing are another terms used for size
reduction.

4. OBJECTIVES OF SIZE REDUCTION
In the material processing industry, size reduction is usually carried out in order to:
 It improves appearance
 Milling of ointments, pastes and creams give them smooth texture and elegant
appearance.It also improves physical stability.
1) It increase surface area:
Specific surface is increased by size reduction which increase dissolution rate and hence
therapeutic efficiency increases.
2) It facilitates mixing:
Size reduction make mixing more easier and more uniform and assure uniform dose.

5. 3) It facilitates absorption:
The rate of absorption depends on the particle size. Finer the particles quicker will be the
rate of absorption.
 FACTORS AFFECTING SIZE REDUCTION
 Hardness Toughness
 Stickiness Slipperiness
 Moisture content Melting point
 Material structure

6. METHODS OF SIZE REDUCTION
1) CUTTING(Slicing):
Material is cut into pieces. It may be effected by a sharp penknife, a pair of scissors or
a root cutter.
2) COMPRESSION(Bruising):
Material is crushed by application of pressure.it is carried out by pestle and mortar in
laboratory while by roller mills in industry.
3) IMPACT:
Impact occurs when material is stationary and is hit by an object moving at high
speed.

7. SIZE SEPARATION
 After the drug has been grind, this process will contain wide range of
particle size. It is sometime necessary to separate the particles
according to their size. This process of fractionation of particles on the
basis of size range is known as grading or sifting or size separation
methods.
 Sieving or sifting is one of the simplest and most frequently used
methods for separation of different grades of powders.
 The ordinary sieves used in pharmacy consist of a circular frame made
up of wood or metal which is fitted with wire, made up of copper
alloys, silk, nylon having uniform, circular cross section.

8. Importance of size separation
 To formulate a uniform dosage form
 To prepare granules of required size
 To separate undesirable particles
Different methods of size separation
 Sieving method
 Sedimentation method
 Cyclone separation method

9. LEACHING
 Leaching is a process of extracting a substance from a solid material
that has come into contact with a liquid. It is a type of solid-liquid
extraction.
 In leaching, the liquid is very important as it facilitates the ability to
remove a given substance from a solid matrix.
 Leaching can be batch, semi batch, or continuous. It usually operates
at an elevated temperature to increase the solubility of the solute in
the solvent.

10. EXAMPLE
 The process goes like that.
 To add hot water to a cup.
 And now steep the green tea bag into it.
 Not only the color changes but also the green is extracted from the
bag into the cup.
 And after steeping some then take a sip from the cup there is not
only hot water but a delicious green tea.

12. INDUSTRIAL APPLICATIONS
 Leaching is widely used in the biological and food processing industries.
Such as the separation of sugar from sugar beets with hot water.
 The extraction of oils from peanuts, soybeans, sunflower seeds
 In pharmaceutical industries many products are obtained by leaching
plant roots, leaves and stems.
 It is used for extraction of tannin from tree barks using water.
 It is used for extraction of perfumes from flowers.
 It is also used for preparations of tea and coffee.

13. EVAPORATION
 “Evaporation means simply vaporization from the surface of a liquid.
Vaporization of a liquid below its boiling point is called evaporation.”
 It is the removal of liquid from a solution by boiling the solution in a
suitable vessel and withdrawing the vapour, leaving a concentrated liquid
residue.
 This means that heat will be necessary to provide the latent heat of
vaporization and, in general the rate of evaporation is controlled by the
rate of heat transfer.

14. APPLICATIONS OF EVAPORATION
 Manufacturing of bulk drugs
 Manufacturing of biological products
 Manufacturing of food products
 Manufacturing of de mineralized water

15. DRYING
 Drying is defined as the process in which the liquid is removed from a material by
application of heat.
NEEDS OF DRYING
 To make product stable.
 Preparation of powder and granules.
 Reducing the bulk and weight. So cost of transportation and storage
decreases.
 Drying lead to produce more stable product as water causes bacterial
and mold growth.
 A drying operation involves transfer of heat, and rate of water removal is determined
by the rate at which heat may be transferred.

16. CHOICE OF METHODS OF DRYING
 Product is sensitive to heat or not.
 Nature of solvents to be removed.
 Process is to be carried out under aseptic condition.
 Quantity of products to be dried.
 Available source of heat.
 TYPES OF DRIERS
 Convection Dryers
 Vaccum-Compartment dryer
 Tunnel dryer
 Spray dryer