Powders and Granules in Pharmaceutics
Powders and granules are solid dosage forms commonly used in pharmacy. They may be used directly by patients or used as intermediates for preparing tablets, capsules, and other formulations. These dosage forms are simple, stable, and easy to prepare.
What Are Powders?
Powders are dry, finely divided solid particles that may contain one or more active ingredients mixed with suitable excipients. They may be used externally or internally depending on the purpose.
Characteristics of Pharmaceutical Powders
- Dry and free-flowing
- Can be easily mixed with other ingredients
- Provide fast drug absorption
- Can be used for patients who cannot swallow tablets
Types of Powders
1. Insufflations
Insufflations are medicated powders used for blowing into body cavities such as the nose, throat, ear, or vaginal cavity. They must be very fine to avoid irritation.
Features
- Applied using an insufflator (blowing device)
- Sterile, especially for ENT applications
- Used for local action
Examples
- Nasal powders for infections
- Throat insufflation powders
2. Dusting Powders
Dusting powders are dry powders meant for external use on skin. They protect the skin, absorb moisture, reduce friction, and may deliver medicines like antifungals.
Features
- Used externally only – never applied to open wounds
- Must be very fine and smooth
- Should be free from harmful microbes
- Packed in sifter-top containers for easy sprinkling
Examples
- Talc powder
- Antifungal dusting powders
- Baby powder
3. Effervescent Powders
Effervescent powders release carbon dioxide when mixed with water due to a reaction between acids (like citric or tartaric acid) and carbonates/bicarbonates (like sodium bicarbonate). The fizzing action improves taste and helps dissolve the drug faster.
Features
- Produce a refreshing fizzy solution
- Mask unpleasant taste
- Rapid absorption
- Must be stored in airtight containers to avoid moisture
Examples
- Vitamin C effervescent powder
- Oral rehydration effervescent powders
4. Effervescent Granules
Effervescent granules are similar to effervescent powders but are available in granule form. Granulation reduces dustiness, improves stability, and makes the product more attractive and easier to handle.
Features
- Contain acids and carbonates/bicarbonates
- Release CO₂ when mixed with water
- More stable than effervescent powders
- Pleasant taste due to fizz
Examples
- Effervescent antacid granules
- Energy-boosting fizzy granules
What Are Granules?
Granules are larger, dry aggregates of powder particles. They flow better, are less dusty, and dissolve faster than powders. Granules are used widely in preparing tablets and sachets.
Advantages of Granules
- Better flow properties than powders
- Less dusting and easier handling
- Reduced segregation of ingredients
- More stable and good for hygroscopic drugs
Packaging of Powders and Granules
- Sachets
- Wide-mouth containers
- Sifter-top tins (for dusting powders)
- Airtight containers (for effervescent products)
