Will the HPMC empty capsules be softened or expanded if placed in a humid environment for a long time?

Yes, long-term storage of HPMC empty capsules in a humid environment can exacerbate the softening or expansion of the capsule wall. The main component of HPMC capsules is hydroxypropyl methylcellulose, which is a material that is sensitive to moisture. When the capsule is exposed to a humid environment, the moisture in the air will be absorbed by the capsule, causing changes in its internal structure. Firstly, the inhalation of moisture can cause the capsule to absorb moisture and expand, causing the capsule wall to become soft and lose its original rigidity and stability. This softening may lead to a decrease in the sealing of the capsule, and even problems such as rupture, leakage, or dissolution.
In addition, high humidity may also affect the quality of capsule contents, especially for drugs or supplements that are sensitive to moisture. Prolonged exposure to humid environments may reduce their effectiveness or lead to component degradation. Overall, in order to maintain the stability of the structure and contents of HPMC empty capsules, it is necessary to avoid prolonged exposure to humid environments and ensure that storage conditions comply with the manufacturer's recommendations to prevent swelling, softening, or other quality issues.