Continued Process Verification (Stage 3)
The goal of Continued Process Verification (CPV) is to ensure that the process remains in a state of control during commercial manufacture. It involves setting up and maintaining a system for detecting and investigating deviation from expected trends. The program at KBI involves process and product quality data collection, statistical analysis of data to identify undesirable process variation, process performance reviews, a risk-based approach in initiating and investigating for identifying the root cause of an undesirable process variation and implementing a corrective action if required.
There are 2 CPV phases. An initial phase is used to gain enough process experience to establish statistical control limits. During this phase, initial limits are used and are typically based on prior process experience and data from the development phase. The next phase is referred to as the steady-state or the long-term monitoring phase. The control limits during this phase are established based on a longer term performance of the process. These control limits are based more on statistics. In general, statistical control limits are set at the centerline plus and minus three sigma, which approximates to three standard deviations. As a rule of thumb, steady-state limits are typical based about 20-30 data points for each parameter. These limits are not changed without recorded justification.
A CPV plan initiated for each commercial process at KBI. It is considered a living document and is updated as process changes are made or when there is a confirmed shift in process performance (raw material change, etc.).
