The USP method 3 and 7 are the perfect R&D tools for tablets, granules, pellets and powders which require multiple media change in combination with a test run duration of 72 hours max.

 

With USP method 3 and 7, samples are loaded inside acrylic glass test stations (6 or 7) which are sealed by membrane filters so the disintegrated particles remain inside when the test station moves from one row of vessels to the next row (from one kind of media to the next one).  Due to his method of testing up to 6 media changes can be performed automatically. Additional changes can be performed with manual interaction.

 

Another application for USP method 3 and 7 is to perform a dissolution test already in fractions. Instead of taking samples periodically (i.e. after 15, 30, 45 minutes) the complete test-station may be moved from one to the other vessel row at the time of the sampling interval. Therefore the use of USP 3 or 7 may eliminate the sampling procedure, which may be very helpful for those products that normally show problems with sampling due to filtration, tubing, foaming etc.