Empty capsules are one of the most important carriers in the pharmaceutical and health supplement industries, and their physical properties directly relate to drug stability, production efficiency, and final product quality. However, because the main components of capsule shells, whether gelatin or plant fibers, are naturally hygroscopic, they are highly prone to moisture absorption and becoming sticky during storage and use. This not only causes the capsules to deform and stick together, but in severe cases, it can also lead to equipment jamming and the deterioration of the contents. So, how can you effectively prevent empty capsules from absorbing moisture and turning sticky?
1. Strictly Control the Temperature and Humidity of the Storage Environment
This is the core measure to prevent moisture absorption. Empty capsules are extremely sensitive to their environment. The optimal storage conditions for gelatin capsules are typically a temperature of 10°C-25°C and a relative humidity (RH) of 35%-65%. Within this range, capsules maintain an optimal moisture content (usually between 13%-16%), preventing them from becoming brittle due to excessive dryness or soft and sticky due to moisture absorption.
When the ambient humidity exceeds 65%, capsules will rapidly absorb moisture from the air, causing the shells to soften and become sticky. Furthermore, when the temperature exceeds 30°C, the accelerated molecular motion intensifies the risk of capsule deformation and adhesion. Therefore, the warehouse must be equipped with comprehensive temperature and humidity control systems, such as air conditioners and dehumidifiers, along with real-time data monitoring to ensure constant storage conditions.
2. Optimize Packaging and Transportation Management
Packaging serves as the first line of defense for capsules against external moisture. It is recommended to use high-barrier packaging materials, such as aluminum foil bags or sealed drums with desiccants. During transportation, direct sunlight and rain must be strictly avoided. Especially during cross-regional transport, significant temperature fluctuations can easily generate "condensation", leading to moisture inside the packaging. To counter this, pre-condition the temperature inside the shipping container or use buffer materials to ensure the goods remain in a cool, dry environment throughout the journey.
3. Standardize Operating Procedures in the Production Workshop
Capsules are most vulnerable to ambient humidity after their outer packaging is removed and they enter the production area. Firstly, the workshop should maintain a clean environment with compliant temperature and humidity (it is recommended to control the RH in the filling area between 35%-50%). Secondly, adhere to the principle of "open only when needed" to minimize the capsules' exposure time to the air. For unpacked capsules, use well-sealed turnover bins for storage and avoid multi-layer stacking to prevent physical adhesion caused by compression. Additionally, never leave capsules sitting in the filling machine hopper for extended periods, as the heat generated by the equipment or ambient humidity can cause localized moisture absorption.
4. Strengthen Stacking and Warehouse Detail Management
When stacking in the warehouse, hard pallets must be used, and placing capsule cartons directly on the floor is strictly prohibited to block ground moisture. Maintain a distance of at least 10 cm between the pallets and the walls to ensure proper air circulation. Meanwhile, keep them away from direct air conditioning vents, heaters, and other heat sources to prevent localized high temperatures that can soften and stick the capsules. Controlling the stacking height is also crucial to avoid the bottom-layer capsules from bearing excessive weight, which can lead to deformation and breakage.
In summary, avoiding moisture absorption and stickiness in empty capsules requires systematic management across multiple dimensions, including temperature and humidity control, packaging protection, production operations, and warehouse details. Only by establishing scientific maintenance standards can you ensure that every capsule serves the end product in its optimal condition.
