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Designing and Operating Pharmaceutical Cleanrooms

  • 2024-03-03
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A pharmaceutical cleanroom is an enclosed controlled environment specifically engineered to have extremely low levels of airborne particles like dust, microbes, and aerosol particles Clean rooms are essential for manufacturing pharmaceutical drug products and medical devices to ensure quality, safety, and efficacy. They provide contamination-free space critical for aseptic processing and testing of pharmaceuticals.

Designing and Operating Pharmaceutical Cleanrooms

ISO Cleanroom Standards

The International Organization for Standardization (ISO) has established standards for testing and monitoring cleanrooms:

ISO 14644-1: Classification of air cleanliness by particle concentration

ISO 14644-2: Specifications for monitoring air cleanliness

ISO 14644-3: Test methods for classifying cleanroom performance

Cleanroom Classifications

Cleanrooms are classified from ISO Class 1 to Class 9 based on the number of particles ≥ 0.5μm permitted per cubic meter of air. For example:

ISO Class 5: 3,520 particles/m3

ISO Class 7: 352,000 particles/m3

ISO Class 8: 3,520,000 particles/m3

Lower class numbers indicate cleaner rooms. Pharmaceutical processes often require ISO Class 5 to 8 cleanrooms.

Design and Construction of Pharmaceutical Clean Rooms

Cleanroom design and construction aims to control contamination risks. Key factors include:

Layout and Zoning

Cleanrooms are laid out to segregate higher cleanliness areas from lower cleanliness areas. Personnel and material flow is planned to minimize contamination.

Walls, Floors and Ceilings

Surfaces are smooth, non-shedding, and resistant to particles and chemical residues. Specialized materials like vinyl, epoxy resin, and stainless steel are used.

HVAC System

Sophisticated heating, ventilation and air conditioning (HVAC) systems provide clean, filtered air. Positive pressure prevents contamination ingress. Multiple air changes per hour are typical.

Air Handling Units

Air handling units filter and provide conditioned air to maintain temperature, humidity and cleanliness. High-efficiency particulate air (HEPA) filters remove >99.97% of particles ≥0.3μm.

Air Filters

Prefilters remove large particles, while HEPA and ULPA (ultra-low particulate air) filters trap tiny particles down to 0.1μm. Regular filter testing and replacement is crucial.

Utilities and Monitoring Systems

Clean utilities like pure water, clean steam, compressed gases, and vacuum systems serve cleanroom processes. Environmental monitoring verifies that operating parameters are met.

Cleanroom Equipment

Cleanrooms feature specialized equipment designed to minimize contamination risks, including:

Gowning Room

Personnel enter through gowning rooms, where they wear protective garments like coveralls, gowns, boots, gloves, hair/beard nets and face masks.


Interlocking doors maintain pressure differentials between cleanroom areas, while allowing parts and personnel to pass through.

Pass Boxes

Items are transferred in and out of cleanrooms through pass boxes - receptacles with interlocked doors to prevent simultaneous opening.

Cleanroom Operations

Maintaining cleanrooms requires:

Cleaning and Disinfecting

Routine cleaning using pure water, isopropyl alcohol, hydrogen peroxide or other permitted agents removes residues. Disinfectants kill microorganisms.

Environmental Monitoring

Continuous monitoring of differential pressure, temperature, humidity, microbial counts and particulate levels verifies that the cleanroom meets specifications.

Applications of Pharmaceutical Clean Rooms

Cleanrooms enable:

Aseptic Processing

Aseptic manufacturing of injectable drugs, ophthalmic preparations and sterile powders relies on cleanrooms for an ultraclean environment.

Quality Control Testing

Cleanrooms provide contamination-controlled spaces for laboratory testing of pharmaceutical samples, ensuring validity of results.

Trends and Innovations

Emerging trends include modular softwall cleanrooms robotic cleaning technologies and advances in HVAC and filtering systems to achieve higher cleanliness standards. Remote monitoring and automation are also on the rise.

Proper cleanroom design operation and maintenance is critical for pharmaceutical quality and safety. As pharmaceutical technologies advance, cleanrooms will continue adapting to meet stringent contamination control needs.


Pharmaceutical cleanrooms are complex, highly-controlled facilities engineered to attain stringent air purity levels. From design and construction to equipment and operation, cleanrooms employ specialized techniques to eliminate risks of microbial, particulate and chemical contamination. With pharmaceutical processing advancing and quality standards increasing, innovations in cleanroom technologies will be vital to ensuring the highest levels of sterility and quality.


What is the cleanest cleanroom classification?

ISO Class 1, with only 10 particles/m3 ≥ 0.1μm is the cleanest cleanroom classification. However, ISO Class 1 rooms are rare, only required for the most critical aseptic processes. Most pharmaceutical cleanrooms are ISO Class 5-8.

How is air cleanliness maintained in a cleanroom?

Through HEPA and ULPA filtration coupled with positive pressure, frequent air changes, low-shedding materials, strict gowning procedures, cleaning protocols and constant particulate monitoring.

What is an airlock in a pharmaceutical cleanroom?

An airlock is an enclosed space with interlocked doors that allows parts and personnel to pass between adjoining cleanroom areas while maintaining air pressure differentials.

What are cleanroom garments made of?

Cleanroom operators wear garments made of special fabrics like polyester, polypropylene, nylon or blends selected for low particle generation. Multiple layers and full coverage are common.

How often should a pharmaceutical cleanroom be recertified?

Cleanrooms should be recertified every 6 months according to ISO standards. This involves retesting airborne particulates to verify the room still meets the original cleanliness classification.

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