Bird's eye view of technology applied in pharmaceutics and other industries like food industry in order to preserve the thermolabile compunds.

3. • Definition:
Freeze drying is the removal of ice or other
frozen solvents from a material through the
process of sublimation and the removal of
bound water molecules through the process
of desorption.
The name lyophilization is derived from the
Greek for ‘to make solvent-loving’.

4. • Lyophilization and freeze drying are terms that
are used interchangeably.
• Controlled freeze drying keeps the product
temperature low enough to avoid changes in the
dried product appearance and characteristics.
• Excellent method for preserving a wide variety of
heat-sensitive materials such as:
– Proteins
– Microbes
– Pharmaceuticals
– Tissues & plasma.

6. Objectives of lyophilization process:
• To preserve the biological activity of a product.
• To reduce the product weight to lower the
transportation cost.
• To extend the shelf life or stability.
• To dry thermolabile materials.
• To eliminate the need for refrigerated storage.
• To get accurate, sterile dosing into the final
product container.

7. Instrument used for lyophilization:
The instrument used for lyophilization is called
lyophilizer or freeze-dryer.

8. Steps for lyophilization
• Pretreatment of Formulation
• Loading of Container (Bulk, Flask, Vials)
• Freezing (Thermal Treatment)of formulation at
atmospheric pressure
• Primary Drying (Sublimation) under vacuum
• Secondary Drying (Desorption) under vacuum
• Backfill & Stoppering (for product in vials) under
partial vacuum
• Removal of Dried Product from Freeze Dryer

9. • freeze-drying should yield a product that has a
short reconstitution time with acceptable
potency levels.
• Potency is the concentration (EC50) or dose
(ED50) of a drug required to produce 50% of
that drug’s maximal effect.
• The process of adding a diluent to a dry
ingredient to make it a liquid, is called
reconstitution.

10. • Conditions for lyophilization:
 The pressure inside the freeze dryer must be
below the “triple point value” for the product
 The temperature of the sample is maintained
below its freeze point in the lyophilization
process.

11. Stages of lyophilization:
– Pre-freezing
– Primary drying
– Secondary drying

12. • Pre-freezing
The sample is frozen, which means the water
in the product is converted to ice, thereby the
phase has changed from liquid to solid. Slow
pre-freezing will produce lager ice crystals,
which are easier to lyophilize, whilst fast pre-
freezing results in smaller crystals.

13. • Primary drying
 Sublimation starts
 Ice is sublimized into vapours
 vapors are collected at condenser (here, vapours
are again fused into ice)
 Energy is provided by gently-heating the sample.
 Avoid excess heating (in this case, condenser
unable to condense vapors with escalating risk of
sample melting)

14. • Secondary drying
 Removal of tightly bound water molecules
 This water has high vapor pressure than that of
water in its free form due to strong bonding with
sample
 Higher temperature and low pressure is applied,
but keeping in view the fact that any biological
activity must not be impaired
 This process is Desorption

15. Application
• Pharmaceutical and biotechnology – to
increase the shelf life of products, such as
vaccines and other injectable.