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1. Name: Mayur Vithoba Watpade
Class: S.Y.B Pharm
Topic: Equilibrium moisture content
Measurement of EMC
Applications of EMC

2. Equilibrium moisture content
It is the amount of water present in the solid
which exerts a vapour pressure equal to the
vapour pressure of the atmosphere surrounding it.
EMC is a condition at which the material is neither
gaining or loss moisture .
This moisture content is retained by the solid
under steady state conditions.

3. Desorption
When an air (of constant temperature and humidity) is
continuously passed over the solid containing moisture
more than EMC, then solid loses over till EMC is
reached. This phenomenon is known as desorption.
Sorption
When an air (of constant temperature and humidity) is
continuously passed over the solid containing moisture
less than EMC, then solid adsorbs water continuously till
EMC is reached. This phenomenon is known as Sorption.

5. Measurement of EMC :
•The solids are placed in a series of closed chambers such
as desiccators.
•Each chamber consist of a solution (dessicant),which
maintains a fixed relative humidity in the enclosed air
spaces.( In other words, the solid samples are exposed to
several humidity conditions.)
•The exposure is continued until the material attains a
constant weight (i.e. equilibrium condition)
•The difference in the final and initial weights gives the
moisture content.

6. •The moisture content is measured twice ;before
keeping the material into the storage bin and while
taking out the material for processing the next step
(compression).
•During storage ,material may gain / lose moisture.
•Many materials have inherent properties of gaining
(hygroscopic) or loosing (efflorescent) moisture
even during storage.
Formula :
Moisture
content
(%) =
Weight of water in sample
Weight of dry sample
100

7. Applications of EMC:
Drying Processes:
Drying should be stopped when the moisture content
reaches the level of the EMC under the exposed conditions.
Storage Conditions:
Ensures proper storage conditions for food products by
preventing under-drying (which can lead to microbial
growth) or over-drying (which can reduce product quality).

8. Drug Stability:
Ensures that pharmaceutical products are stored at
appropriate moisture levels, which can affect the
potency and stability of certain medications.
Packaging:
Influences the choice of desiccants and packaging
materials used for moisture-sensitive drugs.

9. THANK YOU !!