This is a ready-to-use performance qualification (PQ) protocol for a dry heat depyrogenation tunnel or batch oven. Replace every <<FILL: ...>> placeholder with your own specifics, set your document numbers and dates, attach the calibration and endotoxin-indicator certificates, and route it through your normal document control, review, and approval. It assumes installation and operational qualification are complete. A worked filled specimen follows the template. Verify each cited standard against the current source before you rely on it. This is educational reference content, not regulatory advice; adapt it to your own systems and confirm the requirements that apply to you.
Approval page
| Field | Entry |
|---|---|
| Protocol title | Dry Heat Depyrogenation Performance Qualification |
| Protocol number | <<FILL: PQ-ID, e.g. PQ-STE-021>> |
| Version | <<FILL: version, e.g. 1.0>> |
| Equipment / system | <<FILL: tunnel or oven name and asset ID>> |
| Product / component in scope | <<FILL: vial size / component>> |
| Site / area | <<FILL: site, room, grade>> |
| Role | Name | Signature | Date |
|---|---|---|---|
| Author (Validation) | <<FILL>> | ||
| Reviewer (Microbiology / QC) | <<FILL>> | ||
| Reviewer (Engineering SME) | <<FILL>> | ||
| Approver (Quality Assurance) | <<FILL>> |
1. Objective
To demonstrate, with documented evidence, that the dry heat depyrogenation process operated at its worst-case (least-lethal) validated parameters achieves a minimum 3.0 log10 (1000-fold) reduction of a known bacterial endotoxin challenge at every worst-case load position, reproducibly across three consecutive cycles, and that the coldest item in the worst-case load accumulates lethality consistent with that reduction. See depyrogenation and dry heat sterilization for the underlying science.
2. Scope
This protocol covers the PQ of the depyrogenation cycle for the equipment and component named on the approval page. It includes heat distribution, heat penetration, and the endotoxin-indicator (EI) biological challenge at worst-case load. It does not cover IQ/OQ (completed under <<FILL: IQ/OQ protocol number>>) or routine requalification (governed by <<FILL: requalification SOP>>).
3. System description
| Attribute | Entry |
|---|---|
| Equipment type | Continuous tunnel / batch oven (<<FILL: select>>) |
| Manufacturer / model | <<FILL>> |
| Hot zone setpoint (validated target) | <<FILL: e.g. 320 C>> |
| Temperature tolerance band | <<FILL: e.g. +/- 10 C>> |
| Belt speed range (tunnel) / hold time (oven) | <<FILL>> |
| Airflow / pressure cascade (tunnel) | <<FILL: infeed / hot / cooling differentials>> |
| Exit environment | <<FILL: e.g. ISO 5 / Grade A unidirectional airflow>> |
4. Prerequisites (verify and record before execution)
| Prerequisite | Evidence / reference | Verified (initial / date) |
|---|---|---|
| IQ and OQ approved and closed | <<FILL: IQ/OQ report number>> | |
| Equipment released from maintenance, no open critical work orders | <<FILL>> | |
| Thermocouples calibrated pre-study against a traceable standard | <<FILL: cal cert numbers>> | |
Data logger calibrated and configured (sampling interval <<FILL: e.g. 10 s>>) | <<FILL>> | |
| EI lot certified, recovered potency > 1000 EU, RSE traceability on file | <<FILL: EI lot / cert>> | |
| Endotoxin assay (USP <85>) method validated for the recovery matrix (no inhibition/enhancement) | <<FILL: method / report>> | |
| Executors trained on this protocol | <<FILL: training records>> |
5. Roles and responsibilities
| Role | Responsibility |
|---|---|
| Validation engineer | Places thermocouples and EIs, executes cycles, calculates FH and log reduction, writes the report |
| Microbiology / QC | Receives/characterizes EIs, performs recovery and USP <85> assay, runs positive controls same day, reports recovered EU |
| Engineering SME | Confirms equipment state and control parameters, supports deviations |
| Quality Assurance | Approves protocol and report, dispositions deviations, owns the validated state |
6. Worst-case rationale
Document why the chosen load and cycle parameters are the worst case, before execution:
- Load:
<<FILL: densest representative load / largest and smallest container / maximum throughput>>. Justify the slowest-heating configuration (densest packing, shielded positions, belt edges, tray centre). - Cycle: least-lethal allowable parameters. Tunnel: maximum belt speed (shortest dwell) at the low end of the temperature band. Oven: minimum hold time at the low end of the band.
- Positions: cold spots identified from OQ distribution data or engineering assessment, listed in section 8.
7. Acceptance criteria
| # | Criterion | Acceptance |
|---|---|---|
| AC-1 | Endotoxin log reduction | Not less than 3.0 log10 at every worst-case position, all three cycles |
| AC-2 | Positive control recovery | Mean recovered EU on unprocessed EIs supports a verifiable challenge of at least 1000 EU, assayed same day, same method |
| AC-3 | Number of cycles | Three consecutive successful cycles at worst-case parameters |
| AC-4 | Temperature uniformity | All distribution thermocouples within the validated band |
| AC-5 | Penetration / lethality | Coldest penetration thermocouple meets the protocol minimum FH / time-at-temperature |
| AC-6 | Thermocouple verification | All thermocouples pass pre- and post-study calibration within <<FILL: e.g. +/- 0.5 C>> |
| AC-7 | Assay validity | USP <85> system suitability and positive product controls pass; no invalidating inhibition/enhancement |
8. Thermocouple and EI placement map
Record the placement so it is reproducible. Co-locate each worst-case EI with a penetration thermocouple.
| Position ID | Location description | Distribution TC | Penetration TC | EIs placed (n) |
|---|---|---|---|---|
| P1 | <<FILL: e.g. belt left edge, leading item>> | <<FILL: TC no.>> | <<FILL: TC no.>> | <<FILL: e.g. 3>> |
| P2 | <<FILL>> | |||
| P3 | <<FILL>> | |||
| PC | Positive controls (unprocessed, same lot) | n/a | n/a | <<FILL: e.g. 3>> |
9. Test cases
TC-1 Thermocouple pre-use verification
| Step | Instruction | Expected result | Actual | P/F | By/Date |
|---|---|---|---|---|---|
| 1 | Verify each TC against traceable standard | All within <<FILL: tolerance>> |
TC-2 to TC-4 Depyrogenation cycles (repeat for cycles 1, 2, 3)
| Step | Instruction | Expected result | Actual | P/F | By/Date |
|---|---|---|---|---|---|
| 1 | Load worst-case configuration per section 6 | Load matches diagram | |||
| 2 | Set least-lethal parameters (max speed / min hold; low end of band) | Parameters confirmed and recorded | |||
| 3 | Place TCs and EIs per section 8 | Placement verified | |||
| 4 | Run cycle; record time/temperature at every TC | Continuous data captured | |||
| 5 | Recover EIs; assay residual by USP <85>; assay positive controls same day | Assay valid; results recorded | |||
| 6 | Compute FH at each penetration TC | Coldest FH meets AC-5 | |||
| 7 | Compute log reduction per position | Not less than 3.0 log10 (AC-1) |
TC-5 Thermocouple post-use verification
| Step | Instruction | Expected result | Actual | P/F | By/Date |
|---|---|---|---|---|---|
| 1 | Re-verify each TC post-study | All within tolerance; any failure invalidates that TC’s data |
10. Log reduction calculation
For each position and cycle:
Log reduction = log10(mean recovered EU on positive controls) minus log10(EU remaining on processed EIs)
Where processed EIs read below the assay detection limit, bound the residual at the detection limit and report a “greater than or equal to” reduction. Record every value on the endotoxin log reduction worksheet.
11. Deviation handling
Any excursion from protocol (a failed TC, an out-of-band cycle parameter, an invalid assay, a reduction below 3 logs) is recorded as a protocol deviation, assessed for impact, and dispositioned by QA per <<FILL: deviation SOP>> before the affected result is accepted. Follow the investigation logic in the parent article before condemning the cycle: rule out recovery and assay problems first.
12. Summary and conclusion
| Item | Result |
|---|---|
| Cycles executed | <<FILL>> |
| All acceptance criteria met | Yes / No |
| Deviations (number, disposition) | <<FILL>> |
| Validated routine parameters set | <<FILL: belt speed / hold, hot zone temp, pressure cascade>> |
| Conclusion | <<FILL: process qualified / not qualified>> |
13. References
USP <85> Bacterial Endotoxins Test; USP <1228> Depyrogenation, <1228.1> Dry Heat Depyrogenation, <1228.5> Endotoxin Indicators for Depyrogenation. FDA Guidance for Industry: Sterile Drug Products Produced by Aseptic Processing, cGMP (2004). EU GMP Annex 1, Manufacture of Sterile Medicinal Products (2022, effective 25 August 2023). EN ISO 20857:2010, Sterilization of health care products, Dry heat. 21 CFR 211.94, 211.113. ICH Q9, Quality Risk Management.
Confirm the current version and clause numbers before issue.
14. Attachments
Calibration certificates; EI lot certificate and recovery method; raw time/temperature data; assay records and standard curves; deviation reports; load photographs.
15. Revision history
| Version | Date | Author | Summary of change |
|---|---|---|---|
<<FILL: 1.0>> | <<FILL: date>> | <<FILL>> | Initial issue. |
Filled specimen
The following shows key sections completed for an example vial depyrogenation tunnel. Company, system, and numbers are illustrative; replace with your own.
System: Depyrogenation tunnel DPT-02, 2R glass vials, feeding an ISO 5 filling line. Validated target 320 C, band +/- 10 C, belt speed 90 to 150 mm/min.
Worst case: Maximum belt speed 150 mm/min (shortest dwell) at 310 C (low end of band), fully loaded belt, worst positions at both belt edges (left/right) and the leading item, from OQ distribution data.
Placement: P1 left edge, P2 right edge, P3 leading centre; 3 EIs and 1 penetration TC per position; 3 positive controls unprocessed.
| Position | Cycle | Mean PC recovered EU | log10(PC) | Processed EI residual | log10(residual) | Log reduction | Result |
|---|---|---|---|---|---|---|---|
| P1 | 1 | 6,300 | 3.80 | < DL, bounded 0.5 EU | -0.30 | 4.10 | Pass |
| P2 | 1 | 6,300 | 3.80 | < DL, bounded 0.5 EU | -0.30 | 4.10 | Pass |
| P3 | 1 | 6,300 | 3.80 | 1.2 EU | 0.08 | 3.72 | Pass |
| P1-P3 | 2 and 3 | 6,300 | 3.80 | < DL to 1.0 EU | -0.30 to 0.00 | 3.80 to 4.10 | Pass |
Lethality: Lowest FH at P1 penetration TC = 58 FH units, above the protocol minimum of 30. All TCs passed post-use verification within +/- 0.4 C. Conclusion: process qualified; routine parameters set at belt speed not above 150 mm/min, hot zone not below 310 C, with continuous monitoring and alarms.
Common inspection findings this protocol prevents
- Reduction calculated from the label claim instead of the recovered positive control.
- A challenge that could not support 3 logs because recovered EU was under 1000.
- Only a typical load validated, not the worst case run in production.
- EIs placed at warm positions while thermocouples sat elsewhere.
- The cycle run at nominal setpoint and speed rather than the least-lethal allowable combination.
- Post-use thermocouple verification skipped, so drifted data went unquestioned.
How to adapt this protocol
- Set your document numbers, equipment ID, and component in the approval page and section 3.
- Fill the worst-case rationale from your own OQ distribution data.
- Enter your real positions, thermocouple numbers, and EI counts in section 8.
- Set your FH minimum and temperature band in the acceptance criteria.
- Point the deviation and requalification cross-references to your real procedures.
- Confirm every reference against its current published version before issue.