With the Flow-Through Cell, fresh media passes continuously across the dosage form. This is called an open loop system. A semi-automated system allows  samples to be taken simultaneously and collected in a fraction collector  or analyzed directly by UV. Complete fractions or aliquotes can be collected in an Off-line open system. It is also possible to collect samples and analyze them.

USP 4 Fixed and Small Volume Dissolution/Elution Testing…For small or fixed volume testing, the flow through cell can re-circulate the media across the dosage form. This is called a closed loop system. This can be an on-line closed loop with UV, micro volume autosampler, and even a manual sampling syringe.

The validation of the USP 4 Dissolution Testing system according to the regulations can be done by a SOTAX specially trained service engineer. The USP requires the flow rate and temperature to be qualified.