What is a Downflow Booth in the Pharmaceutical Industry?

In pharmaceutical manufacturing, Downflow Booths (also called powder containment booths or material transfer stations) are specialized controlled environments designed to safely handle and weigh active pharmaceutical ingredients (APIs), excipients, and other potent compounds. These enclosed workspaces protect operators from hazardous substances while preventing cross-contamination—a critical requirement for GMP compliance.

Many APIs (e.g., oncology drugs, hormones) are highly toxic. Downflow Booths use:

• ✔ HEPA-filtered airflow to capture airborne particles
• ✔ Glove ports for safe material handling
• ✔ Negative pressure to contain hazardous dust

Prevents contamination of sensitive materials by:

• ✔ Isolating the weighing process from room air
• ✔ Minimizing human contact with open powders

Mandated under:

• EU GMP Annex 1 (for sterile products)
• OSHA standards (worker safety)
• FDA 21 CFR Part 211 (cGMP for finished pharmaceuticals)

(OEB = Occupational Exposure Band)

• ✔ Class II Biosafety Cabinet (BSC): Recirculates 70% air, exhausts 30%
• ✔ LEV (Local Exhaust Ventilation): Directs contaminants away from the operator

• ✔ Stainless steel or powder-coated steel for easy cleaning
• ✔ Anti-static work surfaces to prevent particle adhesion

• ✔ Differential pressure sensors (maintain negative pressure)
• ✔ Particle counters (real-time airborne particulate checks)

• ◉ API Weighing & Dispensing
• ◉ Clinical Trial Material Preparation
• ◉ High-Potency Drug Manufacturing
• ◉ Compounding Pharmacy Operations

Pre-Operation Checks

• Verify pressure differentials
• Inspect glove integrity

PPE Requirements

• Respirators (for OEB4+ materials)
• Disposable coveralls

Decontamination

• Wipe down with sporicidal agents after use
• Validate cleaning with swab tests

• ► Robotic Dispensing – Automated arms reduce human exposure
• ► IoT-Enabled Booths – Cloud-based monitoring of pressure/particle data
• ► Single-Use Containers – Eliminate cleaning validation for cytotoxic drugs

Downflow Booths are the first line of defense in pharmaceutical powder handling. By combining engineering controls with strict procedures, they ensure both product quality and worker safety—especially crucial for potent compounds.