1) The raw materials used are different
The main ingredient of gelatin capsules is medicinal gelatin, which is derived from collagen in animal skin, tendons and bones. The main ingredient of hypromellose capsules is 2-hypromellose, which is usually made from cellulose hydrolyzed by plants and is made by etherification.
2) The chemical structure and stability of the capsule shell are different
Lysine remains in gelatin and may undergo cross-linking reactions, while hypromellose is chemically stable and does not undergo cross-linking reactions.
3) The water content is different
The water content of gelatin capsules is about 12.5-17.5%, the water content of hypromellose hollow capsules is about 4%-6%, the water content of gelatin capsules is less than 10%, and the water content of hypromellose capsules will not become brittle even if it reaches 1%, which is more suitable for filling water-sensitive contents.
4) The coating performance is different
The surface of hypromellose capsules is rougher than that of hollow capsules, and the affinity with most enteric coating materials is significantly higher than that of gelatin. The good coating properties of hypromellose make it a significant advantage in the preparation of sustained-release coated capsules and targeted preparations.
5) Additives are different
The main ingredient of gelatin capsule is protein, which is easy to breed and reproduce bacteria and microorganisms, preservatives and bacteriostatic agents need to be added in the production process, which may have residues on the capsule, and ethylene oxide sterilization is also required before packaging of the finished product to ensure the microbial control index of the capsule. Hypromellose capsules do not require the addition of any preservatives during the production process, and ethylene oxide sterilization is not required.
6) Different storage conditions
Tests have proved that hypromellose capsules are almost not brittle under low humidity conditions, and are still stable under high humidity conditions, and there is no problem in storage in all climatic zones.
