Vessel | Centering Rings

Centering

Proper centering is essential for reproducible hydrodynamics in the dissolution test environment. USP <711> specifi es centering be <2 mm. A tighter

specification of <1 mm, which offers a more appropriate centering specifi cation given the tightness of the current specifications, is described in the

mechanical qualification procedures by the FDA and ASTM, as well as the USP Toolkit 2.0. Centering rings can vary from vendor to vendor, and it is

recommended to use the centering rings from the manufacturer of the dissolution apparatus to ensure optimal centering. Also, centering

rings or collar devices should be tight and if they have fi ngers to center the vessel from the internal surface, all should be in place. Loss of one or

more fi ngers in the centering ring or using a faulty collar can greatly reduce the proper centering of the vessel