Storage Guidelines for HPMC Empty Capsules

Storage of HPMC (Hydroxypropyl Methylcellulose) empty capsules must take their material properties and environmental conditions into full consideration to guarantee the capsules' physical stability, chemical inertness and microbial safety. Detailed storage practices and precautions are outlined below:

I. Environmental Storage Requirements

Temperature Control

Recommended storage temperature: 10℃ ~ 25℃ (ambient temperature); extreme temperatures must be avoided.

High temperature hazards: Temperatures above 30℃ may soften, stick or deform capsule shells, compromising filling accuracy.

Low temperature risks: Temperatures below 5℃ can embrittle shells, raising the risk of breakage, especially during mechanical handling.

Humidity Management

Optimal relative humidity (RH): 35% ~ 65%.

Excess humidity: RH above 70% causes capsules to absorb moisture, swell, stick together or develop mold.

Insufficient humidity: RH below 30% dehydrates shells and makes them brittle, damaging sealing performance.

Light & Ventilation

Light protection: Store away from direct sunlight or intense artificial light to prevent UV-induced material degradation.

Ventilation requirements: The storage area must be well ventilated to avoid trapped humid air. However, direct strong airflow should be avoided, as it will over-dry the capsules rapidly.

II. Packaging & Container Selection

Retain Original Factory Packaging

Unused capsules should remain sealed in the original aluminum foil bags or plastic bottles supplied by the manufacturer, which come with desiccants (e.g., silica gel beads) to maintain airtightness. Once opened, consume the capsules promptly. Seal leftover capsules tightly and mark the opening date clearly.

Secondary Packaging Options

Moisture-proof containers: Sealed glass jars or plastic pails lined with food-grade desiccants are acceptable.

Light-blocking outer cartons: For long-term storage, place containers inside light-proof cartons for extra UV shielding.

III. Storage Area Arrangement

Isolation Rules

Keep capsules separated from volatile substances including chemical reagents, disinfectants and fragrances to prevent chemical reactions with HPMC. Do not store alongside strong oxidants (e.g., potassium permanganate) or acidic substances (e.g., hydrochloric acid), which will degrade the capsule material.

Shelving Management

Place capsules flat or upright; tilted storage will cause deformation. Leave a gap of over 10 cm between stacked shelves to facilitate air circulation and prevent localized moisture buildup.

IV. Handling Special Circumstances

Short-Term High-Temperature Exposure

For temporary exposure (less than 24 hours) to 30℃ ~ 35℃ environments (e.g., during transit), add extra desiccants and move the capsules to standard ambient temperature as soon as possible.

Long-Term Bulk Storage Recommendations

Deploy temperature and humidity data loggers to continuously monitor storage conditions; retain recorded data for a minimum of 2 years for traceability. Conduct visual and physical inspection sampling every 3 months: check for sticking or discoloration, and test mechanical properties such as friability and disintegration time.

V. Strict Prohibitions

No Freezing Allowed

Freezing temperatures (below 0℃) trigger crystallization of HPMC. After thawing, capsule shells develop rough surfaces and impair swallowing experience.

Avoid Heavy Compression

Do not stack heavy goods on top of capsule packages. Single-layer stacking height should not exceed 1.5 meters to prevent permanent deformation.

Keep Clear of Contaminants

The storage zone must be isolated from dust, cooking fumes and other pollutants. Surface contamination will compromise the stability of encapsulated contents.