Jul 26,2022

　　There are many types of capsules, in this article, we focus on two types - HPMC capsules and gelatin capsules.

　　According to research, in any dissolution medium with a pH value less than or equal to 5.8, HPMC (hydroxypropyl methylcellulose) capsule shell dissolves rapidly, and there is no difference in the dissolution time in the test temperature range of 10-10 °C. 55°C. Generally, gelatin and PEG capsule shells do not dissolve at temperatures below 30 °C. In mixed phosphate buffer pH = 6.8, the shell dissolution time was prolonged and more variable for all tested capsules. It was found that the addition of enzymes (pepsin, trypsin) to any of the dissolution media did not enhance the differences between the different capsule types studied. The results suggest that capsule formulations should not be taken with carbonated cola-type beverages. Capsules containing gelatin should preferably be taken with hot beverages, while HPMC capsules can be taken with cold or hot beverages. The latter type of capsule should also be preferred for formulations to be taken in the fasted state. Short-term storage of gelatin-containing capsules in hot, humid tropical conditions does not appear to alter the dissolution properties of the shell, and changes in disintegration and dissolution times of formulations filled in such capsules may reflect changes in the incorporated powder rather than the capsule shell. However, brief storage of HPMC capsules under these conditions appears to affect the capsule shell matrix. Short-term storage of gelatin-containing capsules in hot, humid tropical conditions does not appear to alter the dissolution properties of the shell, and changes in disintegration and dissolution times of formulations filled in such capsules may reflect changes in the incorporated powder rather than the capsule shell. However, brief storage of HPMC capsules under these conditions appears to affect the capsule shell matrix. Short-term storage of gelatin-containing capsules in hot, humid tropical conditions does not appear to alter the dissolution properties of the shell, and changes in disintegration and dissolution times of formulations filled in such capsules may reflect changes in the incorporated powder rather than the capsule shell. However, brief storage of HPMC capsules under these conditions appears to affect the capsule shell matrix.

　　Generally speaking, qualified capsules should be completely dissolved within 15 minutes of shaking in water at 37°C, which is similar to the dissolution time of ordinary tablets. Therefore, in general, it dissolves rapidly at body temperature.

　　When the environment is "dry", the water content of gelatin capsules exceeds 10%. It increases rapidly when soaked in moist conditions. It takes about 10-20 minutes for the matrix to soften, twist, and break down.

　　Vegetarian capsules (modified cellulose) start with less than 10% water and hydrate slowly for 30-60 minutes before disintegrating.

　　By the way, one thing we can be sure of is that the water temperature at which we take the capsules has little effect on the release and efficacy of the drug. The reason is that whether cold or hot water is used, the capsules are mostly in an environment around 37°C.