Capsule brittleness is one of the most common quality issues in the pharmaceutical and nutraceutical industries. When capsules become brittle, they may crack, split, or break during filling, packaging, transportation, or storage. This problem not only affects production efficiency but can also reduce product quality and customer satisfaction.
Understanding what can cause capsules to become brittle is essential for capsule manufacturers, supplement brands, and pharmaceutical companies that want to maintain stable capsule performance and extend product shelf life.
Why Do Capsules Become Brittle?
Capsules are highly sensitive to environmental conditions, especially humidity and temperature. Both gelatin capsules and vegetarian capsules require balanced moisture levels to maintain flexibility and structural integrity.
When capsules lose too much moisture, the capsule shell becomes dry and fragile, increasing the risk of brittleness.
Common Causes of Brittle Capsules
1. Low Humidity Conditions
Low humidity is one of the primary reasons capsules become brittle.
Gelatin capsules typically require a storage humidity level between 35% and 65% relative humidity (RH). If humidity drops too low:
Capsule shells lose moisture
Capsules become dry and rigid
Cracking and splitting may occur
This issue is especially common during winter or in air-conditioned storage areas.
2. Improper Storage Temperature
Temperature fluctuations can also negatively affect capsule quality.
Very low temperatures may reduce capsule flexibility, while excessive heat can alter moisture balance inside the capsule shell.
Recommended storage temperature:
15°C–25°C (59°F–77°F)
Maintaining stable environmental conditions is critical for capsule stability.
3. Exposure to Dry Air
Continuous exposure to open air can quickly reduce capsule moisture content.
This often happens when:
Packaging is not properly sealed
Capsules remain exposed during production
Storage containers are frequently opened
Dry air accelerates moisture loss and increases capsule brittleness.
4. Long-Term Improper Storage
Even high-quality capsules can become brittle if stored incorrectly for extended periods.
Poor warehouse conditions, direct sunlight, or inadequate packaging protection may gradually damage capsule shells.
Problems Caused by Brittle Capsules
Brittle capsules can create several manufacturing and product quality issues:
Capsule cracking during filling
Increased product waste
Machine downtime in automatic filling equipment
Poor appearance of finished products
Reduced customer confidence
For pharmaceutical and nutraceutical manufacturers, capsule brittleness can lead to increased production costs and quality control challenges.
How to Prevent Capsules from Becoming Brittle
Maintain Proper Humidity
The most effective solution is controlling storage humidity.
Recommended humidity range:
35%–65% RH
Using humidifiers or climate-controlled storage rooms can help maintain proper conditions.
Store Capsules in Sealed Packaging
Capsules should always remain in their original sealed packaging until use.
Best practices include:
Double-layer PE bags
Fiber drums or sealed cartons
Immediate resealing after opening
Proper packaging helps preserve moisture balance.
Control Storage Temperature
Avoid storing capsules near:
Heating equipment
Air conditioning vents
Direct sunlight
Stable room temperature helps prevent capsule drying.
Allow Capsules to Adjust Before Use
When moving capsules between environments with different humidity levels, allow them to acclimate gradually before production.
This helps reduce stress on capsule shells.
Quality Control in Capsule Manufacturing
Professional capsule manufacturers implement strict quality control systems to minimize brittleness risks.
Quality procedures often include:
Moisture content testing
Capsule flexibility inspection
Environmental monitoring
Batch traceability systems
Manufacturers operating under GMP standards usually maintain stricter environmental controls to ensure capsule stability.
