PVT (Performance Verification Test) is frequently described as necessary to assess the performance of dissolution apparatuses (paddle and basket). Interestingly, the test quite often fails, i.e., test results often fall outside the expected range, without any known reason or cause.
Commonly described reasons/causes are: worn-out ball bearings, loose motor belts, misalignment of spindles or vessels, inaccurate gap between the bottom of spindle and base of vessel, lack of straightness of spindle rods, wobbling, vibration in the instrument and/or around its surrounding, high/low humidity affecting tablets, inappropriate de-aeration of the medium, inaccuracy in measured rpm, variations in vessel dimensions, mismatch of vessels from different suppliers, not using vessels from the instrument supplier, use of plastic vs. glass vessels, using scratched or not clean vessels, not withdrawing a sample from an appropriate position, not appropriately dropping the tablet or pouring the medium in the vessels, lack of an analyst’s training, in addition, any combination/permutation of these reasons.
Most interesting is the fact that there has been no experimental evidence available in support of these claims i.e., there is no experimental data available to indicate that these aberrations provided results outside the expected range. To rationalize its continued use, supporters of the PVT maintain the claim that failures indicate potential deficiencies or aberrations, but how?