Production and Process Controls
This domain tests written production procedures, charge-in and yield controls, in-process controls and time limits, microbiological control, reprocessing, and the process validation lifecycle. Questions often describe an operator improvising a fix and ask what should have happened.
Written procedures and in-process controls
- 211.100(a) requires written procedures for production and process control, including validation, and 211.100(b) requires deviations from those procedures to be recorded and justified.
- 211.101 covers charge-in: each component is weighed or measured at the time of use, verified by a second person, and if weighed in advance it must be identified and stored under controlled conditions.
- 211.103 requires actual yield and percentage of theoretical yield to be calculated at the completion of each appropriate phase.
- 211.105 requires equipment to be identified by status at all times. 211.110 requires written in-process controls and tests, for example tablet weight, hardness, thickness, disintegration and moisture for solid dosage forms, with acceptance criteria linked to the finished product specification.
- 211.111 sets time limits for each production phase; 211.113 requires control of microbiological contamination, with validation of aseptic processes.
- 211.115 permits reprocessing only under written procedures with defined steps and additional testing of the finished batch.
Process validation lifecycle
- Stage 1 is process design, identifying critical quality attributes and critical process parameters and establishing a control strategy.
- Stage 2 is process qualification, covering facility, utilities and equipment, followed by performance qualification of the commercial process. Three consecutive successful batches are the common expectation, though the number must be justified, and worst-case conditions should be challenged.
- Stage 3 is continued process verification, using statistical process control and trending so that the process remains in a state of control over time.
- EU Annex 15 recognises traditional, continuous and hybrid validation approaches, plus ongoing process verification.
Worked example
Blend uniformity at 20 minutes gives a relative standard deviation of 5.8 percent against a limit of 5.0 percent. The operator extends blending to 30 minutes and re-samples only the locations that previously passed. This fails twice: it changes a validated parameter without change control, and it biases the sampling. The correct path is a deviation with an investigation into causes such as particle size distribution, loading order or blender speed, no release on ad-hoc data, and after root cause a change control to re-validate the blending step, followed by performance qualification or a justified bridging study.
Traps that cost marks
- Treating 100 percent inspection or finished-product testing as a substitute for a validated, controlled process.
- Releasing a batch with a yield outside the validated range without investigation.
- Accepting increased blending or drying time as routine operator discretion.
- Forgetting 211.111 time limits and hold times, or ignoring second-person verification of charge-in.