In-Process Controls (IPC) – Monitoring, Adjusting, and Proving Quality While Work Is Being Done

This topic is part of the SG Systems Global regulatory & operations glossary.

Updated October 2025 • Process Control & Release Readiness • See also: SPC Control Limits, CPV, eBMR, eMMR

In-Process Controls (IPC) are the planned measurements, checks, interlocks, and decision points performed during manufacturing, packaging, and testing to ensure a process remains in a state of control and that intermediates/outputs continue to meet specifications. IPCs span quantitative readings (weights, temperatures, viscosities), qualitative verifications (appearance, torque feel, seal condition), identity and status confirmations (lot, expiry, equipment readiness), and statistical monitoring to detect special-cause variation before it becomes nonconformance. Effective IPCs are derived from product and process understanding and are codified in the master recipe or procedure—paper BMR or, preferably, eMMR—then executed and evidenced in the eBMR with contemporary data and signatures.

“Quality is not inspected into the batch at the end; IPCs make quality happen in the middle, one controlled decision at a time.”

In regulated environments, IPCs reduce reliance on end-product testing by pushing assurance upstream. They are a cornerstone of GMP, HACCP-style control plans, and device process validation, linking process parameters to critical quality attributes and enforcing real-time reaction plans. Whether you are dosing a micro-ingredient by gravimetric weighing, sealing a medical pouch with validated temperature/time/pressure, or blending high-risk allergens under segregation controls, the IPC framework decides what to measure, how often, with what instruments, by whom, and what to do if results drift or fail.

1) What It Is

An IPC program translates product requirements and process capability into an operational control plan. At its core are what to monitor (critical process parameters, alarms, and attributes), where/when to monitor (start-up checks, steady-state intervals, changeovers, clean-breaks), how to measure (calibrated instruments, validated methods, sampling schemes), and what to do when data approach or exceed limits (adjust, slow/stop, segregate, open Deviation/NC, invoke CAPA). The plan must integrate with materials control (status at Goods Receipt, Component Release), equipment readiness (calibration, cleaning), and labeling (barcode validation, template/version checks) to close common failure paths.

ICPs are not limited to process parameters; they include verification of identities and statuses that, if wrong, create systemic defects. Examples include scanning and verifying every lot against the eBMR pick list, confirming FEFO/FIFO usage, preventing use of expired or quarantined materials, checking equipment state against qualification and cleaning validation records, and verifying labels and GTIN/UDI data before print/apply. In higher-risk settings, dual-operator sign-off (Dual Verification) and poka-yoke interlocks reduce human error at critical junctures.

2) Regulatory Anchors & Scope

Predicate GMPs embed IPC expectations across sectors. For drugs/biologics, 21 CFR 210/211 require in-process monitoring and control of parameters affecting identity, strength, quality, and purity, with scientifically justified limits and documented results. For food, 21 CFR 117 (PC Human Food) ties monitoring and verification to preventive controls (process, allergen, sanitation), closely aligned with HACCP. Dietary supplements (Part 111) and medical devices (Part 820) likewise require in-process specifications, monitoring, and acceptance activities. When records are electronic, Part 11 and EU Annex 11 apply to signatures and audit trails. Ongoing assurance falls under Continued Process Verification (CPV), where IPC data feed trending and capability analysis.

3) Elements of a Practical IPC Plan

• Control object selection. Identify critical process parameters (CPPs) and key performance indicators (KPIs) that correlate with critical quality attributes (CQAs). Examples: mixer speed/torque, bath temperature/time, moisture, fill weight/torque, seal temperature/dwell, pH, conductivity, viscosity, and foreign-matter controls. Tie each to spec/alert/action thresholds using development/validation studies.
• Measurement method & device. Use calibrated instruments under controlled status (calibration), with traceable IDs recorded in the eBMR. For solids handling, prefer integrated scales and gravimetric weighing to avoid transcription. For packaging, capture sealer/bander set-points and verified readings.
• Sampling plan. Define where and how often to check: 100% device capture, periodic at-line samples, start-up and post-changeover checks, and intensified sampling after deviations. For attributes, align with AQL where relevant.
• SPC & limits. Establish control limits and rules (e.g., Western Electric) to detect drift. Distinguish spec limits from control limits to avoid tampering.
• Reaction plan. For each IPC, define specific actions at alert and action thresholds: adjust parameters, slow/stop, segregate WIP, open Deviation/NC, trigger CAPA, and document re-inspection or rework criteria.
• Identification & status control. Enforce barcode validation for item/lot/label scans; require dual verification for high-risk substitutions; bind labels to approved templates with scan-back; ensure FEFO material usage.
• Environment & hygiene. Where relevant, hook checks to EM and cross-contamination control: room differentials, temperature/humidity, allergen changeovers, cleaning verifications.
• Documentation & review. Capture contemporaneous data in the eBMR with signatures and audit trails. Enable QA review-by-exception before Batch Release and CoA issue.

4) Sampling, Measurement, and Statistical Control

Sampling and measurement strategy should reflect risk to product and patient/consumer. For high-impact parameters (e.g., API potency, seal integrity), capture device data continuously or at every unit; for moderate impact, define rational subgroups and frequencies; for low risk, rely on start-up checks and periodic verification. Apply measurement system analysis during validation to confirm that gauges and methods can resolve decisions at the chosen limits. Use SPC charts appropriate to data type (X̄-R, X-mR, p/np, c/u) and distinguish common-cause from special-cause variability to avoid over-correction. IPC findings should also feed capability analysis (C_p, C_pk) and longer-term CPV trending. When IPC results indicate loss of control, invoke the reaction plan immediately: segregate affected WIP, trace genealogy using Batch Genealogy, open a deviation, and assess impact on previously produced units.

5) Data Integrity & Electronic Records

ICPs only protect you if the data are complete, accurate, and attributable. Enforce ALCOA+ via Part 11 controls: unique user identities, role-based permissions, e-signatures with meaning, secured audit trails for creation/modification, and time synchronization across MES/LIMS/WMS/labeling. Minimize free text and prefer device capture—from weighing scales, HMIs, counters, and printers—to reduce transcription and backdating risk. Manage master changes under Document Control and Change Control, and retain raw data/metadata per Data Retention & Archival. Where applicable, event-level traceability via EPCIS strengthens chain-of-custody from material receipt through finished goods.

6) Common Failure Modes & How to Avoid Them

• “Check at the end.” Late discovery creates scrap and recalls. Fix: move checks upstream, add device interlocks, and define reaction plans that stop defects at source.
• Uncalibrated or poorly understood instruments. Results lack credibility. Fix: enforce calibration status and method validation; evidence in eBMR.
• Spec limits used as control limits. Over-adjustment increases variability. Fix: set statistically derived control limits and train operators on SPC rules.
• Identity/label errors bypass controls. Wrong lot/label causes systemic defects. Fix: bind barcode validation and dual verification into critical steps.
• Weak exception handling. Deviations discovered during QA review, not at line. Fix: auto-open Deviation/NC at point of failure with photos and reason codes.
• Paper or spreadsheet silos. Lost context and backdating risk. Fix: move execution to eBMR with device capture and trails.
• Training lag vs. effective dates. Operators follow outdated IPCs. Fix: link releases to Document Control training completion.

7) Metrics That Demonstrate IPC Effectiveness

• Right-First-Time (RFT) rate and cycle time from batch start to QA disposition.
• IPC failure/alert rates per 1,000 opportunities and response time from alert to containment.
• Prevention KPIs: blocked wrong-lot/label attempts; prevented out-of-spec fills/seals; percentage of device vs. manual data capture.
• SPC capability: C_p/C_pk trends for critical parameters; % time in state of control.
• Deviation profile: IPC-originated deviations, recurrence rate, and CAPA effectiveness.
• Inspection readiness: time to render IPC evidence set (raw data, trails, signatures, genealogy) for an inspector.

8) How This Fits with V5

V5 by SG Systems Global implements IPCs as executable controls within the production workflow. In V5 MES, the eMMR defines IPC points, limits, sampling, instruments, and reactions; device integrations capture readings from scales, HMIs, counters, and printers; barcode validation and dual verification enforce identity; and exceptions automatically open Deviation/NC with photos and reason codes. SPC widgets visualize control status and drive review-by-exception in QA. V5 WMS supplies material status and enforces FEFO/FIFO in picks; V5 QMS controls Document Control, Change Control, and CAPA; and the integrated record supports fast Finished Goods Release with CoA generated from controlled data. For traceability, EPCIS events can represent key IPC checkpoints, and the entire dataset sits under Part 11/Annex 11 controls with secured audit trails and retention.

9) FAQ

Q1. How do IPCs differ from end-product testing?
IPCs prevent defects by controlling process parameters and statuses while work is underway; end-product testing detects defects after the fact. Regulators expect both, but well-designed IPCs reduce dependence on destructive or time-consuming final tests.

Q2. Who owns the IPC plan?
Cross-functional ownership: process development defines CPPs/CQAs, quality approves limits and methods, operations executes and records, and QA reviews exceptions before release.

Q3. What if an IPC result is out of trend but within spec?
Treat as early warning: adjust per reaction plan and consider heightened sampling. Use SPC to distinguish drift from noise; document decisions in the eBMR.

Q4. Can we sample less if capability is high?
Potentially, through Change Control with justification (capability data, risk assessment) and maintained CPV. Ensure no unintended risk to identity/label/allergen controls.

Q5. How do IPCs interact with allergen and hygiene controls?
IPCs should include verified clean breaks, swab results where applicable, and segregation checks tied to High-Risk Allergen management and Cleaning Validation.

Q6. What evidence must be retained?
Raw data, metadata (who/what/when/why), instrument IDs and calibration status, calculations, signatures, and audit trails, retained per Data Retention & Archival.

Q7. Are visual inspections valid IPCs?
Yes when methods are defined, inspectors trained/qualified, and results recorded. For high-risk attributes, supplement with objective checks or poka-yoke interlocks.

Related Reading
• Process & Statistics: SPC Control Limits | CPV | FMEA
• Materials & Identity: Barcode Validation | FEFO | FIFO | GS1 / GTIN
• Execution & Release: eMMR | eBMR | CoA | Finished Goods Release
• Governance & Integrity: 21 CFR Part 11 | Audit Trail (GxP) | Document Control | Change Control
• Environment & Hygiene: Environmental Monitoring | Cleaning Validation | High-Risk Allergen