Problems of failures of calibration/ Performance Verification Testing (PVT) are not new. These have been with us since their introduction in the USP. Presently, the issue is not of the failures of calibration/PVT, which is very well established, but how it should be addressed.
To address the issue, let us break down the testing, calibration/PVT or drug dissolution testing in general in different components.
(1) Calibration/PVT Tablets
(2) Dissolution testing procedure and/or analyst training/experience
(3) Apparatuses (paddle/basket)
(1) Calibration/PVT Tablets: At present, there is no independent mechanism available or used to establish the quality or reproducibility of the tablets. The quality and reproducibility of calibration/PVT are established using the paddle/basket apparatuses themselves. Therefore, the quality and reproducibility of the tablets, hence failures, are dependent on the characteristics of the apparatuses used. Using statistical analyses, studies from the USP clearly demonstrated that PVT tablets do not significantly contribute to the failures (1, 2).
(2) Dissolution testing procedure and/or analyst training/experience: In this regard, one should note that dissolution testing means dropping a tablet/capsule into the vessel containing a medium maintained at 37ºC and starting the stirrer (spindle) at a pre-set rpm, followed by withdrawing a sample from the vessel. It is extremely important to note that an associated or required analytical technique such as spectrophotometry or chromatography is not part of the dissolution testing or testers. An analyst can conduct a dissolution test independent of the analytical (quantitation) technique and may send the samples to another analyst/analytical laboratory physically located hundreds of miles away to determine drug levels from dissolution testing using techniques of their choice. Read the rest of this entry �