Efflorescent Powders
- S-1-Pharmaceutics I
- Feb 27
- 2 min read
Updated: Apr 9
Efflorescent powders refer to a class of pharmaceutical powders that contain hydrates, which are substances that have water molecules incorporated into their crystal structure.
When these hydrates are exposed to a low-humidity environment or are subjected to heat, they can release water molecules, a process known as efflorescence.
Although efflorescent powders aren't a specific type of dosage form, they are found across various pharmaceutical formulations.
Types of efflorescent powders

Bulk powders
Divided powders
Topical powders
Dusting powders
Advantages of efflorescent powders
1) Improved solubility
The presence of water molecules in the crystal structure can improve the solubility of certain substances, which can be beneficial for drug absorption.
2) Hydration benefits
Efflorescent powders can help maintain hydration of some formulations, which may be useful for topical applications or other dosage forms where moisture content is critical.
Disadvantages of efflorescent powders
1) Stability issues
The release of water molecules can alter the physical and chemical properties of the powder, potentially affecting its stability, appearance, and flow properties.
2) Sensitivity to environmental conditions
Efflorescent powders are sensitive to humidity and temperature changes, which can affect the rate of water release and the stability of the product.
3) Potential for weight loss
The loss of water through efflorescence can cause a decrease in weight, which can impact the accuracy of dosing.
Examples of efflorescent powders
1) Sodium carbonate decahydrate (washing soda)
This substance, although not a pharmaceutical product, is an example of an efflorescent powder. When exposed to air, it loses water molecules and becomes sodium carbonate monohydrate.
2) Epsom salts (magnesium sulfate heptahydrate)
Commonly used as a laxative or for soaking, Epsom salts can lose water molecules when exposed to air, leading to a change in their appearance and texture.
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