What is the lifespan of HPMC empty capsules?
The lifespan of HPMC (hydroxypropyl methylcellulose) empty capsules is typically 2-3 years, but the specific duration is affected by factors such as storage conditions, packaging, production process, and usage environment.
I. Lifespan of HPMC Empty Capsules
Under normal storage conditions, sealed HPMC empty capsules stored in a cool, dry environment at a temperature of 15-25°C and a humidity of 35-65% generally have a lifespan of 2-3 years.
For short-term use, if the capsules are filled with a drug and sealed in a blister pack or aluminum-plastic packaging, their lifespan may be shortened to 1-2 years, depending on the drug's stability (e.g., hygroscopicity and chemical activity) and the barrier properties of the packaging material.
II. Key Factors Affecting the Lifespan of HPMC Empty Capsules
1. Storage Conditions
Temperature: High temperatures (>30°C) accelerate the degradation of the HPMC molecular chain, causing the capsules to become brittle or deform.
Low temperatures (<5°C) may cause the capsules to harden, but generally do not permanently damage them. They can be used normally after returning to room temperature. Humidity: When humidity is too high (>70% RH), HPMC absorbs moisture and expands, potentially causing capsules to stick, crack, or change size.
When humidity is too low (<30% RH), capsules may become brittle due to water loss, increasing the risk of breakage.
Light: Ultraviolet rays or direct sunlight accelerate HPMC oxidation. Storage in a dark environment (e.g., using a light-proof container or aluminum foil packaging) is recommended.
2. Packaging
Sealing: Unopened original packaging (e.g., a double-layer aluminum foil bag) effectively blocks moisture and oxygen, extending the capsule's shelf life to over three years.
Opened capsules that are not promptly sealed should be used within one month or stored in a dry, airtight container.
Packaging Materials: Aluminum-plastic blister sheets or PVC/PVDC composite film offer superior barrier properties compared to ordinary plastic bottles, extending the capsule's shelf life by 6-12 months.
3. Production Process and Raw Material Quality
HPMC Purity: High-purity HPMC has a stable molecular structure and a longer shelf life; industrial-grade HPMC may contain impurities that accelerate degradation. Additives: Appropriate additions of plasticizers such as glycerin and sorbitol can improve capsule flexibility, but excessive amounts may increase hygroscopicity.
Excipients such as pigments and opacifiers may affect stability and require accelerated testing.
4. Operating Environment
Drug Properties: Hygroscopic drugs may increase internal humidity in the capsule, shortening its lifespan.
Alkaline or acidic drugs may corrode HPMC, so select chemically resistant capsule models.
Equipment Cleanliness: Residual lubricant or metal particles in the equipment during the filling process may contaminate the capsules and cause premature failure.
5. Practical Tips for Extending the Lifespan of HPMC Empty Capsules
Optimize Storage Conditions: Store capsules in a dedicated medicine cabinet or a constant temperature and humidity chamber to avoid contact with volatile substances (such as fragrances and detergents).
Use a temperature and humidity recorder to monitor the environment to ensure compliance with standard requirements.
Standardize Packaging Management: Immediately seal the package with sealing clips or a vacuum sealer after opening to minimize exposure to air.
Avoid repeated opening and closing of the packaging bag to prevent moisture ingress. Regular Quality Inspections and Visual Inspections: Observe capsules monthly for discoloration, sticking, cracking, or deformation.
Microbial Limits: Test annually for total bacterial count, mold, and yeast to ensure compliance with hygiene standards.
6. End-of-Life Disposal: Do not use: Expired capsules may degrade due to HPMC, resulting in prolonged disintegration time, affecting drug efficacy, and even producing harmful degradation products.
