1)The use of different raw materials
Gelatin is the main component of pharmaceutical gelatin capsules, gelatin derived from animal skin, tendons, bone collagen. The main component of HPMC capsules 2 - hydroxypropyl methyl cellulose, is typically obtained by the hydrolysis of plant cellulose, prepared by etherification.
2）The chemical structure of the capsule shell, different stability
Lysine remaining gelatin, crosslinking reaction may occur, and HPMC chemically stable, cross-linking reaction does not occur
3）Different water content
Gelatin capsules moisture content of about 5% -7%, HPMC capsules moisture content of about 4% to 6%, water content less than 10% gelatin capsules become brittle, and the water content of HPMC capsules is not even 1% become brittle, more suitable for filling water sensitive contents.
4）Different coating performance
HPMC capsules rougher than the surface of hollow capsules, enteric coating material with affinity Most significantly higher than gelatin. HPMC good coating performance, so in the preparation of controlled release capsules and coating type targeting agents have a distinct advantage.
5）Different additives
The main ingredient is a protein gelatin capsules, easy to breed bacteria and microbes multiply the production process need to add preservatives and antimicrobial agents, which may have a residual in the capsule, and also the need to use pre-finished packaging ethylene oxide sterilization methods to ensure that the capsule microbial control targets. HPMC capsules and the production process does not require adding any preservatives and without ethylene oxide sterilization.
6）Different storage conditions
The test proved, HPMC capsules hardly become brittle at low humidity conditions, under high humidity conditions remained stable in all climatic zones within the storage is no problem.