Physical degradation refers to changes in the physical properties of a drug formulation, such as appearance, hardness, particle size, and organoleptic properties. Some common types of physical degradation include loss of volatile components, loss of or absorption of water, crystal growth, polymorphic changes, and color changes. To prevent physical degradation, formulations should be stored in well-closed containers in cool places, stabilizers may be used, and exposure to light and moisture should be avoided.

1. Physical Degradation :
• Definition :
• It is the degradation which results into the change of physical
nature of drug. The formulation is totally changed by way of
appearance, organoleptic properties, hardness, brittleness,
particle size.
• Physical degradation includes:
• Loss of volatile components
• Loss of water
• Absorption of water

2. • Crystal growth
• Polymorphic changes
• Colour changes
• 1. LOSS OF VOLATILE COMPONENTS:
• Volatile components such as alcohol, ether, camphor, iodine, volatile
oil etc. escape from the formulation e.g. Nitroglycerine from drugs
evaporates.

3. Measures to Prevent Loss of Volatile
Components:
• Such products should be placed in well closed container.
• To decrease temperature as increase in temperature will increase
volatility, product should be placed in a cool place.
• 2. LOSS OF WATER:
• Loss of water from o/w emulsions thus the stability changes.
• Water evaporates from efflorescent salts such as Borax and sodium
bisulphate etc.
• Water evaporates causing crystal growth.

4. Measures to Prevent Loss of Water:
• Water loss may be prevented by storing the product in well closed
container.
• 3. CRYSTAL GROWTH:
• In solutions after super saturation of solvent crystal growth occurs
e.g. injection of calcium gluconate
• In suspension crystals settle down and caking occurs and suspension
becomes unstable e.g. ophthalmic preparations.

5. Prevention of Crystal Growth:
• In case of solutions stabilizers are employed.
• In case of suspension minimum temperature flocculation should be
managed.
• Incorporation of surface active agents.
• By increasing viscosity of suspending medium.
• 4. ABSORPTION OF WATER:
• Hygroscopic drugs such as glycerin suppositories absorb
• Water from atmosphere causing physical degradation.

6. Preventive measure for absorption of water:
• Product should be placed in well closed container.
• 5. POLYMORPHIC CHANGES:
• In polymorphic changes crystals form change. A stable crystal form is
lost.
• Measures to prevent polymorphic changes:
• Formulated product should contain a stable crystalline form of the
drug.

7. 6. COLOUR CHANGES:
• Colour changes are of two types:
• Loss of color
• Development of color
• Loss of color is due to pH changes.
• Development of color is due to reducing agents, water and U.V rays.
• Prevention of Colour Changes:
• PH should not be changed.
• Exposure to light should be avoided.