In pharmaceutical manufacturing, the purity of raw materials is paramount. Any contamination introduced during the sampling process can compromise the entire batch, leading to product failure and regulatory issues. This is why strict procedures, often involving a Sampling Booth, are essential to avoid airborne contamination.
This article outlines the standard operating procedure (SOP) used in pharmaceutical facilities to ensure raw material sampling is conducted in a clean environment.
🎯 The Purpose of Sampling Booths
The main objective during raw material sampling is to avoid airborne contamination that could compromise the quality of the material.
Sampling booths are engineered to create a “clean environment” by continuously moving filtered air across the working area. This air purification system is critical:
- Air Intake: Fresh air is initially drawn into the system.
- Pre-Filtration: The air first passes through a Core Filter and then a 5 Micron Filter. These are cleanable filters designed to reduce the particle load, protecting the final, most sensitive filter.
- Final Filtration: The air then passes through the HEPA (High Efficiency Particulate Air) Filter, which removes 99.97% of particles 0.3 microns and larger, ensuring the air inside the booth is ultra-clean.
⚙️ Operating the Sampling Booth: Ensuring Clean Air Flow
Proper operation and monitoring of the sampling booth are mandatory for maintaining its effectiveness.
1. Daily System Checks
- Pre-Sampling Activation: Switch ‘ON’ the mains and the lights. Start the blower at a slow speed one hour before sampling begins. This allows the system to establish the required clean air curtain and pressure cascade.
- Differential Pressure (DP) Reading: The pressure inside the booth is constantly monitored using a manometer. Note the reading daily.
2. Manometer Readings and Maintenance
The manometer reading, typically measured in mm of water, indicates the pressure drop across the filters. This tells us the condition of the filters:
| Reading Range | Condition Indicated | Action Required |
| 7 to 15 mm of water | Recommended Operating Range | System operating optimally. |
| Greater than 15 mm of water | Choking of the HEPA filter | Requires replacement of the HEPA filter. |
| Lower than 7 mm of water | Choking of the Pre-Filter | Requires cleaning of the pre-filter. Inform the engineering department. |
Important Note: Whenever the HEPA filter is replaced, the system must be validated by performing a PAO (Poly-Alpha-Olefin) test to confirm filter integrity and leakage detection.
📏 Step-by-Step Raw Material Sampling Procedure
To maintain the clean environment and prevent contamination, strict operational guidelines must be followed:
- Keep System ON: Always open material containers for sampling only when the sampling booth system is ‘ON’.
- Sampling Execution: Sample the material according to the specific raw material sampling SOP.
- Contained Sampling: Do not take the sampling device outside of the booth. Collect the sample into a closed container inside the booth itself to avoid spillage outside the clean zone.
- Device Cleanliness: Use a clean sampling device for every different material sampled to prevent cross-contamination.
- Post-Sampling Check: After sampling every raw material container, note the manometer reading again as a quality check.
- Container Closure: Close the polybag or containers of the sampled material under the laminar flow unit within the booth before removing them.
- System Shut Down: Put ‘OFF’ the system after all sampling activities are complete.
Following this detailed procedure—from starting the blower an hour early to monitoring differential pressure and strictly handling materials within the clean zone—is vital for regulatory compliance and ensuring the consistent quality of pharmaceutical products.https://iampharmacist.com/2025/06/08/q6a-q6b/