FAQs: Dissolution Performance Verification Testing (PVT)

1. Where are the acceptance criteria for the current lot of USP Prednisone Tablets Reference Standard catalog #1559505? I have heard that you have to calculate the geometric mean and %CV of your data. How is that done?

The USP Certificate for the USP Prednisone Tablets RS provides the acceptance criteria and formulas for the calculations.  Although the certificate provides the procedure for calculating the geometric mean and %CV for your Performance Verification Test (PVT) data, a more detailed discussion was provided in a Stimuli to the Revision Process article by Walter Hauck, et al., entitled "Description of the Upcoming Change in Data Analysis for USP Dissolution Performance Verification Tests" PF 34(6) [Nov–Dec 2008].  To help analysts with this calculation, USP has provided a Web-based tool; see Calculation Tool for the PVT of Dissolution Assemblies.

2. How many runs have to be performed for the Performance Verification Test (PVT)?

USP's current approach for PVT calls for the performance of two consecutive runs including all positions of a dissolution instrument (Single-Stage Test approach).  The combined results for both runs will be evaluated and compared with the acceptance criteria corresponding to the Single-Stage approach.
Moreover, USP has implemented a Two-Stage Test approach that allows the analyst to evaluate the results of the first run and compare it with the acceptance criteria corresponding to the first stage (run) of the Two-Stage approach. If the results are within the first-stage acceptance criteria, the PVT test can be stopped at this stage.

In case of an assembly with 12 or 14 positions, a single run (with all positions tested) is required for the PVT.

3. Did the method to perform the PVT using the current lot change from the previous lot?

The method to perform the PVT has not changed from the previous lot.  USP provides some recommendations to help customers achieve a successful PVT in the Dissolution Toolkit. The procedure for the PVT is given in the USP Certificate.

4. What is the storage condition for USP Prednisone Tablets RS catalog #1559505?

USP Prednisone Tablets RS should be stored as per the label.  Please refer to General Chapter <659> for storage and handling definitions.

5. When does a particular lot of USP Prednisone Tablets RS catalog #1559505 expire?

Unlike other USP Reference Standards, a Period of Validity is provided on the USP Certificate of USP Prednisone Tablets RS.  This date is final and will not be extended. A specific lot should not be used after its assigned valid use date.

6. Can I round the PVT dissolution results to whole numbers for calculation?

Per General Notice Section 7.20, numbers should not be rounded until the final calculations for the reportable value have been completed. Intermediate calculations may be rounded for reporting purposes, but the original (not rounded) value should be used for any additional required calculations.  In particular, the percent dissolved values should be retained to at least three decimals prior to calculation of the geometric mean and %CV.

7. What should I do if the PVT for Apparatus 1 passes and then fails for Apparatus 2?

If nothing but the stirring elements are changed when switching from Apparatus 1 to Apparatus 2, then the PVT for Apparatus 1 is considered to be successful.  The cause of failure should be investigated and any adjustments made.  If the cause is the paddle stirring elements and no other changes are made, the PVT has to be repeated for Apparatus 2 only.  If any changes are made other than the replacement of the paddle stirring elements, the PVT should be repeated for both Apparatus 1 and Apparatus 2.

Please contact Reference Standard Technical Services (rstech@usp.org) with USP Reference Standard questions. For questions related to USP monographs, please email stdsmonographs@usp.org. For questions related to NF monographs, please email nfmonographs@usp.org. Please contact Customer Service (custsvc@usp.org) for questions related to orders.