Almost every dissolution test relies on samples being taken to produce a result. It is important that the sampling method does not adversely affect the accuracy of the dissolution test. Sampling errors are very common and are often the cause of erroneous results.
The USP defines the sampling point as: ”A zone half way between the top of the media and top of the paddle or basket not less than 1 cm from the vessel wall. The sampling position is critical but so too is the type of sampling cannula (also known as a probe) used.”