diploma pharmacy note

1. Heat Process
Phr.Nirmal Raj Marasine
(B. Pharm.TU, M. Pharm clinical
pharmacy PU)
WHSA

2. HEAT
 Heat is that form of energy which is transferred from
one object to another, when there is difference in
temperature between the objects.
TEMPERATURE
 Temperature is the degree of hotness and coldness
of an object. When an object is heated, its temperature
increases but when the object is cooled, its temperature
decreases.
HEAT TRANSFER
 Heat transfer refers to the actual flow of heat energy
between the two objects. Heat energy flows from a
system at higher temperature to a system at lower
temperature.

3. Methods of heat transfer
Conduction
During conduction , the transfer of heat from one part
of a body to another part takes place by the
transference of momentum of individual molecules
,without any displacement of particles. The best
example- heating up the whole length of rod when one
end is heated.

4. • Convection-
During convection , the transfer of heat takes place
from one point to another in a body by actual
movement of particles.
For example-heating of water in glass beaker
Radiation
 During radiation, the transfer of heat energy from the
source of heat to the object takes place through space
by means of electromagnetic waves, which travels in
straight line at the speed of light.
• For example- we get heat from the sun by means of
radiation

5. NAME OF DIFFERENT HEAT PROCESS
Sublimation
Distillation
Drying
Exsiccation
Desiccation
Fusion
Calcination
Ignition/Incineration
Evaporation

6. EVAPORATION
Evaporation is the process of removal of solvent from
the solution by boiling the liquid in a suitable vessel
and withdrawing the vapour, leaving a concentrated
product.
Evaporation is a process of vaporizing large
quantities of volatile liquid to get a concentrated liquid .
Evaporation is a surface phenomenon .i.e. mass
transfer takes place from the surface
.

7. Applications of Evaporation
1. Evaporation process is used in the manufacture of
bulk drugs, particularly in pharmaceutical industries.
2. Evaporation is used in the manufacture of biological
products. e.g. Insulin, enzymes and hormones.
3. In demineralization of water

8. Evaporators
There are three types of evaporators
• Natural circulation evaporators
Evaporating pans
Evaporating still
• Forced circulation evaporators
• Film evaporators
• Climbing film evaporators

9. EVAPORATING PAN
• Evaporating pan consists of a hemispherical pan
made from copper or stainless steel and surrounded by
steam jacket.
• The hemispherical shape provides a large surface area
for evaporation.
• The evaporators are mounted in such a way that they
can be tilted to remove the product.
• The evaporating pans are heated by steam which
passes through a steam jacket.

11. ADVANTAGES
They are simple , easy and cheap to construct.
They are easy to use and clean.
Stirring of the evaporating liquids can be done easily.

12. DISADVANTAGES
It is usually used for evaporation of aqueous
liquids.
Higher temperature may cause decomposition of
drugs.
Rate of evaporation is slow.
The layer of saturated vapour formed above the
liquid surface provides additional resistance for
evaporation.
The vapours directly mix with atmosphere that may
cause respiratory disorders and other toxicities.
Due to ununiform heat distribution,the materials
near to wall of the pan may form viscous barrier or
get charred.

13. Evaporating still
• The evaporation still is nothing but covered
evaporating pan to avoid loss of vapour.
• The collected vapour are passed to a condenser,
where these condenses into liquid
• The cover is clamped to close and it can be opened for
cleaning the pan

15. ADVANTAGES
The costly organic solvent can be recollected.
No pollution or inhalation toxicity.
By attachment of vacuum, it can be used for
thermolabile materials.
Rapid process.
It can be operated under reduced pressure.
It is simple to construct and easy to clean and
maintain.

16. DISADVANTAGES
Limited heating surfaces.
Poor utility for heat sensitive materials.
Poor heat transfer coefficient.

17. FACTORS AFFECTING EVAPORATION
There are eight factors to affect evaporation.
1. Temperature
2. Surface area
3. Agitation
4. vapour pressure
5. Time of evaporation
6. Type of product required
7. Economic factors
8) Moisture content of the feed

18. 1) Temperature: The rate of evaporation is directly
proportional to the temperature.
2) Surface area: The rate of evaporation is directly
proportional to the surface area of the vessel
exposed to evaporation.
3) Agitation: is necessary for evaporation.
4) vapour pressure: The rate of evaporation is
directly proportional to the vapour pressure of the
liquid.

19. 5)Time of evaporation
If the time of exposure is longer, greater will be the
evaporation provided the constituents are thermostable.
6) Type of product required: The selection of the
method and apparatus to be used for evaporation
depends upon type of product required. Evaporating
pan or still will produce liquid or dry product, but film
evaporators will produce only liquid products.
7) Economic factors: When selecting the method and
apparatus the economic factors are important

20. 8) Moisture content of the feed
Some drug constituents undergo hydrolysis readily in
presence of moisture at high temp
To prevent decomposition ,the material is exposed to
lower temp initially ,then exposed to higher
temperature for final concentration

21. THANKYOU