A Audit Compliance

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AUDIT COMPLIANCE REPORT INCORRECT SIEVE SIZE USED DURING MILLING

PharmaGuide Hub

July 5, 2026

Process Step Involved

The milling operation was performed after dry mixing and prior to final blending.

The purpose of milling is to:

Achieve uniform particle size distribution.
Improve blend homogeneity.
Ensure consistent flow properties.
Support uniform compression and dissolution characteristics.

Use of an incorrect sieve may alter particle size distribution and potentially impact critical quality attributes of the product.

4.0 ROOT CAUSE ANALYSIS (DETAILED)

Investigation Methodology

The investigation team utilized:

5 Why Analysis
Fishbone (Ishikawa) Analysis
Review of SOPs
Review of Batch Records
Personnel Interviews
Training Record Verification
Equipment Usage Review

4.1 Man (Personnel)

Findings

The production operator selected the sieve from the equipment storage area without independently verifying the sieve number against the MBR.

The line supervisor also failed to verify the installed sieve during equipment setup verification.

Evidence

Operator interview confirmed reliance on visual identification.
Supervisor checklist lacked specific sieve verification entry.
No second-person verification was documented.

4.2 Method (Procedure)

Findings

The existing SOP for milling operation required verification of equipment cleanliness and assembly but did not explicitly require documentation of sieve size verification.

Evidence

Review of SOP No. XXXXX showed:

No mandatory recording of sieve number.
No dual verification requirement.
No photographic verification system.

4.3 Machine (Equipment)

Findings

Multiple sieve sizes were available for the same milling machine.

Identification markings on some sieves had become partially worn due to repeated cleaning and usage.

Evidence

Physical inspection revealed:

Engraving visibility reduced on several sieves.
No color coding system existed.

4.4 Material

No material-related deficiency was identified.

Raw materials complied with approved specifications.

4.5 Measurement

No independent verification mechanism existed to confirm sieve size prior to batch processing.

The setup verification process relied solely on visual inspection.

4.6 Environment

The sieve storage rack contained multiple sieve sizes in adjacent locations.

Although organized, the arrangement increased the possibility of selecting the wrong sieve.

5.0 WHY ANALYSIS

Problem:

Incorrect sieve size used during milling.

Why 1

Why was the incorrect sieve used?

Because the operator selected a 1.5 mm sieve instead of a 1.0 mm sieve.

Why 2

Why did the operator select the wrong sieve?

Because sieve identification was not clearly verified against the MBR.

Why 3

Why was identification not verified?

Because SOP did not require documented sieve verification.

Why 4

Why did the supervisor not detect the error?

Because no independent verification step existed.

Why 5

Why was no independent verification required?

Because the risk associated with sieve selection had not been adequately addressed during procedure development.

6. ROOT CAUSE CONCLUSION

The root cause of the deviation was determined to be:

Inadequate procedural controls for verification of sieve size during milling operations, combined with insufficient visual identification and absence of independent verification during equipment setup.

Contributing factors included:

Lack of mandatory sieve verification in SOP.
Absence of dual-check system.
Worn sieve identification markings.
Lack of color coding and visual controls.

7. SHORT-TERM ACTIONS

Immediately after detection:

Milling operation was stopped.
Affected batch was placed under QA quarantine.
Deviation was initiated.
Product samples were collected for additional testing.
Particle size distribution testing was performed.
Blend uniformity testing was conducted.
Finished product testing was expanded.
All sieve sizes in the area were inspected.

Production personnel were briefed regarding the deviation