Will HPMC empty capsules become brittle if left for a long time?

HPMC empty capsules usually do not become brittle after prolonged storage.
The moisture content of HPMC capsule shells is relatively low, generally between 5% and 8%, and some even lower than 3%, which is much lower than the moisture content of gelatin capsule shells (12.5% to 17.5%). The low water content characteristic makes HPMC capsule shell have good moisture resistance and physical stability. Even during long-term storage, HPMC capsule shells exchange moisture with the environment, and their moisture content will not exceed 9% within the specified packaging for 5 years, which is far below the moisture threshold that causes gelatin capsule shells to become brittle.
In addition, HPMC capsule shell also has good chemical stability, excellent compatibility with most substances, and is not prone to chemical reactions that may cause performance changes. Therefore, HPMC empty capsules can still maintain their original toughness and stability after long-term storage, and are not easily brittle.