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Problems and solutions in the use of the dissolution sinker

Dec. 06, 2018

We continue to explain the contents of the dissolution sinker  today.


A China customer sent us an email. He works for a pharmaceutical company and had some doubts about the use of the dissolution sinker.


He is working on the release quality of a sustained release capsule, sustained-release pellets. Soon the problem appeared.

The capsule is placed in the container and floats above the liquid level, then he uses the settling basket and the capsule sinks smoothly into the bottom of the container.

 The test found that the capsule shell quickly dissolved. However, due to the hindrance of the dissolution sinker, the sustained-release pellets do not rotate well with the stirring paddle, but it is fixed in the settling basket, and the data is also low. 

Then he flipped through the 05 version of the Pharmacopoeia and the 05 version of the standard operating procedures and found that in the use of the basket, it seems that the two books are different.


1. Except for certain specific varieties, the dissolution sinker cannot be used. When all other varieties are used for dissolution, as long as the dosage form floats on the liquid surface, it is placed in a dissolution sinker, placed in a dissolution cup, and then measured.

2. If the dosage form is floated when measured by the small cup method, it should be suspended at the bottom by using a wire winding method, and the dissolution sinker cannot be used.


He has three questions.

1. If there is no standard in the standard to add the sinker, when the preparation floats on the liquid surface, do you need to add a sinker to sink it into the bottom of the cup?

2. If the release of the sustained release preparation (the content is pellet), the capsule floats, then need to add a sink basket to sink it into the bottom of the cup?

3. If the sinker is added, the sinker will restrict the pellet's rotation in the release solution, and will certainly have some influence on the pellet's release rate. How to solve this problem?


We are a manufacturer and we are not professional in the dissolution test of capsules, but in order to solve this customer's problem, we asked our old customers. Here are his suggestions.


1. If there is no stipulation in the standard, the dissolution sinker can only be used when tablets or capsules float on the liquid surface, but other preparations can not.

2. If there is no special requirement for slow-release and controlled-release preparations not to use dissolution sinker, need not be exactly what you want to study.

3. Sustained and controlled release preparations are often greatly influenced by the determination methods, and the domestic research and development level is low, which is still in the baseless establishment and cannot be consistent within vivo release methods to control the quality of sustained and controlled release preparations.


Today's blog is written here, I hope to help users.

If you have any other questions about the dissolution sinker or the metal filter , please leave a message.


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