Comparative Advantage Analysis of Gelatin and HPMC Capsules
HPMC has good properties of film formation, dispersion,water retention and protection of colloids. And it is widely used in medicine and food.
What is the effect of HPMC hollow capsules on disintegration and dissolution?
1.Chemical structure
Gelatin is prone to condensation and cross-linking. Therefore, if gelatin is used, a disintegration delay occurs during capsule placement. HPMC is a partial methyl group and a part of polyhydroxypropyl ether of cellulose, which is chemically stable and does not crosslink. So it does not cause delay in disintegration of HPMC hollow capsules.
2. Disintegration method
The study found that the capsule drug dissolution rate of HPMC hollow capsules was greater than that of gelatin hollow capsules (the reference drug was theophylline).
The reason is that the disintegration of HPMC is that the entire hollow capsule disintegrates at the same time. But the disintegration of the gelatin hollow capsule first disintegrates at the network structure, and then the disintegration of the entire hollow capsule. So HPMC hollow capsule is highly recommended as a speed. A hollow capsule of the release preparation.
3.Hollow capsule water content
It has been found that the gelatin hollow capsules become brittle when the water content is less than 10% .But the water content of the HPMC hollow capsules does not become crisp even if it reaches 1%.
Under the condition of 20~25℃ and RH40%~60% . For gelatin hollow capsules the water content of is about 13%~15%. And HPMC hollow capsules is about 4%~6% under these conditions. In the case of excessive water content, the stability of the moisture sensitive drug has a great influence.
If the hygroscopic capsule is used, the moisture will be transferred to the contents, which will cause the hollow capsule to become hard and brittle, eventually leading to delayed disintegration. This is not the case with HPMC hollow capsules .
Especially in areas with large differences in humidity, the effect on gelatin is more pronounced. Gelatin hollow capsules become brittle in low temperature environments. In a high-humidity environment, the phenomenon of adhesion of hollow capsules occurs. The same regional environmental differences have little effect on HPMC hollow capsules.
In summary of the above mentioned conditions, HPMC hollow capsules should be used for both conditions. First, dry and wet sensitive drugs. Secondly, highly hygroscopic drugs.
