Study on the quality of sustained-release capsules
ASK （questions from customers）
I am now doing a quality study on the release of sustained-release capsules, the contents of which are sustained-release pellets. Now the problem is that the sustained-release capsule is floating on the liquid surface when it is put into the dissolution cup, so I use a dissolution sinker to sink it to the bottom of the dissolution cup. However, it was found in the experiment that the capsule shell dissolved quickly, but due to the obstruction of the sinker, the sustained-release pellets could not rotate well with the impeller, but were fixed in the sinker, and the data was also low.
Then I went through the Pharmacopoeia of the 05 edition and the standard operating procedures of the 05 edition, and found that in the use of dissolution sinker, it seems that the two books have different opinions.
1. In the penultimate line of appendix 73 of Pharmacopoeia (05 Edition), “… In 6 dissolution cups (unless otherwise specified, if the tablet or capsule floats on the liquid surface, it should be put into the dissolution sinker first, and its shape and size are shown in Figure 3)…”
My understanding: In addition to the provisions that the dissolution sinker can not be used for some specific varieties, the dissolution of all other varieties, as long as the dosage form floats on the liquid surface, should be put into the sinker, put into the dissolution cup, and then determined.
2. In the ninth line from the bottom of appendix 74 of Pharmacopoeia (05 Edition), “…… put it in each dissolution cup (for capsule determination, if the capsule floats up, a small section of corrosion-resistant fine wire can be wound around the capsule shell lightly).”
My understanding: Only for the third dissolution method, if the dosage form floats when the small cup method is used, the method of wire winding should be used to make it sink at the bottom instead of using the dissolution sinker（Note: if the settlement basket can be used, it should directly say that the dissolution sinker is used instead of wire）。
3. “05 edition of standard operating procedures” P253, “6.6 requirements for the use of the dissolution sinker… But only when the requirements for the use of the dissolution sinker are specified in the variety theory can it be used.”
My understanding: if there is no provision for the use of dissolution sinker in the variety theory, it can not be used（Note: this seems to contradict the statement in the penultimate 8 th line of appendix 73 of Pharmacopoeia 05）.
- If there is no requirement to add a basket in the standard, when the preparation floats on the liquid surface, does it need to add a drop basket to sink it into the bottom of the cup?
- If the capsule floats when making the release degree of sustained-release preparation (the content is pellets), does it need to add a dissolution sinker to sink it into the bottom of the cup? If the sinker is to be added, the rotation of the pellets in the release solution is limited by the sinker, which must have a certain impact on the release degree of the pellets. How to solve this problem? (in my opinion, if the content of the capsule is powder or soluble particles, the addition of dissolution sinker has little effect on its release rate).
On the above issues, I hope you can participate in the discussion.