The following article has been authored by John Heaney.
The debate about the prednisone performance verification test (PVT) versus the ASTM enhanced mechanical calibration has gone on since the inception of ASTM chapter 2503. Both are different means of providing an answer to the same question,” Is my dissolution tester suitable for use and can I trust the data from it?”
The prednisone PVT is typically performed after a mechanical qualification of the dissolution tester which, if one follows USP 711, has wider tolerances for passing than ASTM 2503. However, if one follows the suggestions in USP Guideline on Procedures for Mechanical Calibration and Performance Verification Test Apparatus 1 and Apparatus 2 (Mar 2023), then the recommended mechanical tolerances are largely in line with those in ASTM 2503. Another note is that prednisone tablets have both a specification for a geometric mean, as well as a coefficient of variation; so having a vessel which has centering at the edge of the tolerance but passing, combined with other vessels which are centered nearly perfectly can potentially cause a failure as if the vessel was out of tolerance.
So where is the advantage to running a PVT? Unlike an ASTM enhanced mechanical qualification, a PVT provides a wholistic test of the dissolution tester, the laboratory, and (if performed with in-house staff) the operator. The prednisone calibrator tablets are designed to fail if any aspect of the dissolution tester, or the process of the testing (e.g. sampling, deaeration, dissolution media, standard preparation) is out of tolerance.
However, the PVT is time consuming. For a trained operator to perform both a mechanical qualification as well as the PVT the instrument will typically be unusable for 2 to 3 days. There are also chances for failure completely unrelated to whether the dissolution tester is within all necessary specifications. The test can fail due to operator errors or errors with equipment unrelated to the dissolution tester.
The ASTM enhanced mechanical qualification has the advantage that it focuses only on the dissolution tester. The operator or other equipment present in the lab do not factor into whether the dissolution tester is suitable for use. There are some key advantages to this, one of the chief ones being the time it takes to perform a mechanical qualification on a dissolution tester is typically only a few hours. The measurements can be performed by most metrology groups without the need for special training on performing dissolution tests.
Without a calibrator tablet though, the ASTM calibration needs a means to determine whether the paddles, baskets, and vessels are within specification. The ASTM calibration checks this by means of either measurement of the dimensions of the apparatus, or alternatively certification from the supplier that the items met all specifications at time of manufacture. This is not required with the PVT because the calibrator tablet performs that check; if the items are within specification the test should pass, if they are out of specification the test should fail.
Which method of qualification is largely dependent on what works best for the lab. The ASTM calibration allows for faster turnaround during the qualification process. The PVT provides proof that not just the dissolution tester, but the lab itself is capable of running dissolution tests correctly, which can be of benefit if the lab is regularly audited. Ultimately both are acceptable by the FDA, and both will answer the question of whether or not your dissolution tester is producing data you can trust.