Sterilization & Depyrogenation Tunnel
Continuous laminar hot air flow sterilization and depyrogenation tunnel operating at up to 350°C with HEPA filtration, delivering a validated 3-log endotoxin reduction for sterile pharmaceutical vials and ampoules.
Description & Operating Principle
HMEC’s Continuous Sterilization and Depyrogenation Tunnel forms the crucial aseptic bridge between high-speed vial/ampoule washing machines and sterile liquid filling monoblocks. Operating under ISO 5 (Class 100) laminar unidirectional airflow throughout all processing zones, the tunnel ensures zero particulate contamination during thermal processing.
Clean, wet containers from the linear or rotary washing machine are automatically fed onto the continuous woven wire mesh conveyor belt. The tunnel is divided into three distinct thermal chambers:
- 1. Infeed Pre-Heating Zone: Laminar airflow gently evaporates residual moisture from washed containers and gradually elevates glass temperature to prevent thermal shock.
- 2. Hot Air Sterilizing & Depyrogenating Zone: High-temperature recirculated hot air (up to 300°C - 350°C) passed through high-temperature HEPA filters achieves a minimum 3-log (99.9%) reduction in bacterial endotoxins / pyrogens.
- 3. Cooling Zone: Sterile Class 100 laminar airflow gradually cools the depyrogenated containers to ambient cleanroom temperature before outfeed directly into the sterile filling barrier (RABS / Isolator).
Target Containers & Applications
Essential equipment for sterile parenteral pharmaceutical filling suites:
💉 Parenteral Glass Vials
Sterilization and pyrogen destruction for 2ml to 100ml tubular & moulded vials for vaccines and biologics.
🧪 Injectable Glass Ampoules
Continuous depyrogenation for 1ml to 20ml glass ampoules prior to inline sterile filling and tip sealing.
🔬 Lyophilization Bottles & Jars
Sterilizing specialized glass containers used in freeze-drying and high-potency API formulation.
👁️ Ophthalmic Cartridges
Sterilization of glass cartridges and dropper bottles requiring absolute endotoxin elimination.
Pros & Cons Comparison
✅ Advantages (Pros)
- Proven 3-Log Pyrogen Reduction: Validated destruction of bacterial endotoxins meeting USP & EU GMP Annex 1 requirements.
- Continuous Inline Flow: Eliminates batch autoclave handling, tray loading, and human intervention risks.
- Full ISO 5 (Class 100) Protection: Unidirectional laminar airflow protects bottles from ambient particles throughout the process.
- Automatic Differential Pressure Balance: Prevents cross-contamination between hot and cold cleanroom zones.
⚠️ Considerations & Limitations (Cons)
- Thermal Heating Power: Requires significant electrical heating capacity (30 kW to 60 kW) during heat-up.
- Warm-Up & Cool-Down Cycle: Requires automated 30-45 minute pre-heating and stabilization time before starting production.
- cGMP design with AISI 304 external panels and heavy-gauge SS 316 / 316L internal heating chambers
- High-temperature HEPA filters (rated up to 350°C) with 99.997% efficiency at 0.3 microns
- Continuous variable-speed stainless steel woven wire mesh conveyor with automatic tensioning
- Automatic dynamic differential pressure balancing between Pre-heat, Sterilization, and Cooling chambers
- DOP / EMERY smoke testing ports for periodic HEPA filter integrity validation
- Multi-point PT100 temperature sensors with multi-channel chart recorder and continuous data logging
- Siemens S7-1500 PLC with 10" Touchscreen HMI and 21 CFR Part 11 electronic batch record compliance
- Emergency backup power connection for cooling fans to prevent heat accumulation during power loss
| Output Speed | Up to 100 to 350+ Vials/Ampoules Per Minute (Conveyor speed & vial volume dependent) |
|---|---|
| Operating Temperature | Up to 350°C (Adjustable recipe setpoint typically 300°C - 320°C) |
| Conveyor Belt Width | 300 mm to 800 mm (Custom width according to line speed) |
| Air Cleanliness Level | ISO 5 (Class 100) unidirectional vertical laminar flow in all three zones |
| HEPA Filter Specification | H14 High-Temperature Glass Fiber Filters (Efficiency: 99.997% at 0.3µm) |
| Endotoxin Reduction | ≥ 3-log (99.9%) reduction validated via Endotoxin Challenge Test |
| Control System | Siemens / Allen-Bradley PLC with SCADA / HMI, audit trail & multi-channel temperature recording |
| Total Power Rating | 30 kW to 65 kW (Heating + Blower Motors + Conveyor Drive) |
| Exhaust Volume | 300 to 600 m³/hr with motorized balancing damper |
Depyrogenation tunnels require minimal mechanical change parts since containers travel side-by-side on the flat mesh conveyor:
- Adjustable Side Guides: Tool-less lateral stainless steel side guide rails adjusted for container height and width.
- Infeed/Outfeed Pusher Plates: Interchangeable transfer finger guides matching bottle neck height.
Q: How is pyrogen destruction validated in the tunnel?
A: Validation is conducted using an Endotoxin Challenge Test (USP <85> and <1211>), inoculating glass vials with a known concentration of endotoxin (e.g. 10,000 EU) and verifying a minimum 3-log reduction post-processing.
Q: How does the tunnel handle pressure differences between cleanroom suites?
A: Differential pressure transmitters continuously monitor air pressures in all three zones. Automated motorized dampers dynamically regulate airflow to ensure sterile air always flows towards lower classification areas.