HPMC empty capsules play a good role in improving product stability, with advantages mainly reflected in the following three aspects. Firstly, according to the 2020 Chinese Pharmacopoeia, the drying weight loss of HPMC empty capsules should be ≤8.0% and the US Pharmacopoeia requires 4%-7%, while the actual production process is generally controlled at 3.0-6.0%. The low moisture content of the empty capsules provides a relatively dry environment for the contents, and the barrier properties of HPMC empty capsules to oxygen and moisture in the air can avoid moisture absorption by hygroscopic contents from the external environment, thereby preventing changes in properties, impurities, microorganisms, etc.
Secondly, environmental temperature and humidity and their brittleness will not change significantly under high temperature and humidity, low temperature and low humidity conditions, thus ensuring the integrity of the capsule and improving the stability of the contents. Finally, the raw materials of HPMC empty capsules are cellulose derivatives, and there will be no cross-linking reaction between amino acids and content components in gelatin capsules.
