Pfizer's Interpretation of Control Strategy Definition and Representation in the Form of the Control Wheel
| Element | Description |
|---|---|
| Element 1: Direct In-Process Monitoring or Control of Product QAsa | Element 1 involves identifying direct in-process monitoring and/or control that is applied throughout the DSb and DPc manufacturing process. This monitoring and/or control relates to attributes that are specifically tested during processing. This element of control is described by the IPTd applied in the process. |
| Element 2: Monitoring or Control of Process Parameters and Material Attributes Functionally Linked to Product QAs | Element 2 involves identifying monitoring and/or control of process parameters functionally linked to QAs. Sources of information to populate this element include upstream and downstream DS process characterization studies, DP manufacturing process characterization studies, and related risk assessments. Monitoring and/or controls for process parameters and material attributes in each unit operation are identified through the risk assessment process described earlier, and any existing functional relationships between those process parameters or material attributes and corresponding QAs are documented. |
| Element 3: Direct In-Process Monitoring or Control of PPAse | Element 3 is similar to Element 1 but differs in that it involves documenting direct monitoring and control of PPAs rather than QAs. As the current discussion focuses on QAs, this element is not explicitly discussed here; however, its documentation ensures appropriate monitoring and controls are in place to ensure consistency of process performance. |
| Element 4: Monitoring or Control of Process Parameters or Material Attributes Functionally Linked to PPAs | Element 4 is similar to the Element 2 but differs in that it involves documenting monitoring or control of process parameters and material attributes that are functionally linked to PPAs rather than QAs. As for Element 3, this element is not explicitly discussed here but is documented and updated to ensure that any modifications in the control strategy do not have a deleterious impact on process performance. |
| Element 5: DS and DP Testing (Release Testing) | Element 5 encompasses the DS and DP release testing and specifications. |
| Element 6: DS and DP Stability Monitoring or Control | Element 6 encompasses the attributes selected to be monitored on stability and the associated acceptance criteria. This element is continually managed in accordance with stability protocols. |
| Element 7: Control of Raw Materials | Element 7 encompasses control of raw materials linked to QAs and/or PPAs. In addition, any raw material controls that are linked to process performance and/or product QAs are documented. |
| Element 8: Facility and Equipment Controls (cGMPfand Procedural) | It is noted that cGMPs mitigate some of the specific risks associated with the manufacture and delivery of particular attributes associated with product. Development of the product-specific control strategy is predicated on the existence of prerequisite programs, including cGMPs and pharmaceutical quality systems for the manufacturing facilities. In documenting Element 8, reliance on cGMPs is noted for specific attributes where relevant. |