In order to preserve the cleanliness and avoid contamination in Pharmaceutical Manufacturing, cleanliness will be a significant factor. A cleanroom is an environment where one can manufacture products according to defined procedures with minimum level of particulate and microbial contamination.
Using a substance pass-box is a simple but effective way to create this controlled environment for transferring material in and out of cleanrooms. Pass Boxes are taken for granted but really are very important because they help reduce the risk of introducing contamination into a cleanroom when transferring materials from one grade of cleanroom to another. Pass Boxes must be manufactured and operated in accordance with Good Manufacturing Practices (GMPs).
In layman's terms, the use of a pass box is a controlled barrier that ensures that items are transferred without compromising the cleanliness of either environment. Common applications for a pass box include:
- Sterile Manufacturing Areas
- Solid Dosage Manufacturing Units
- Microbiology Laboratories
- Packaging Areas
By using pass boxes, the risk of contamination is minimized through:
1. Material is placed in the pass box from one side.
2. The door is closed and interlocked.
3. In dynamic pass boxes, the airflow or UV disinfection will occur after the door is closed.
4. The other side of the pass box will not be opened until the first side door has been closed securely.
5. The material can now be removed from the opposite side of the pass box.
This controlled process will keep the material in the pass box isolated from both areas at all times.
Pass boxes, which are an important tool for pharmaceutical cleanroom design, are simple but vital to maintaining contamination control by helping to ensure the safe transfer of materials between clean areas and non-clean areas.
Properly designing, utilizing and maintaining pass boxes (both static and dynamic) is important for achieving their effectiveness. Following best practices and meeting regulatory requirements will ensure that pass boxes support product quality and cleanroom integrity.
Pass boxes provide an effective barrier, to help ensure safe and compliant operations, in pharmaceutical manufacturing where even very low amounts of contamination can cause significant harm.
What is a pass box?
Pass boxes are used as an effective method of transferring items between a clean room and production area without disturbing the cleanliness of the two areas.In layman's terms, the use of a pass box is a controlled barrier that ensures that items are transferred without compromising the cleanliness of either environment. Common applications for a pass box include:
- Sterile Manufacturing Areas
- Solid Dosage Manufacturing Units
- Microbiology Laboratories
- Packaging Areas
Reasons Why Pass Boxes are Important
Contamination is caused by multiple sources in pharmaceutical cleanrooms, including personnel, equipment and material transfer. Since personnel movement is strictly controlled, equal attention should be given to the transfer of materials between cleanrooms.By using pass boxes, the risk of contamination is minimized through:
- Directly limiting interaction between the clean rooms
- Preventing cross-contamination
- Maintaining static pressure differences
- Reducing traffic through airlocks
Types of Pass Boxes
Pass boxes are divided into two different types depending upon their functions and site class/objective contamination control.1. Static Pass Box
The simplest form of a pass box is the static pass box. It is designed for use between locations with similar classifications. The static pass box is not designed with an airflow system (including air filtration) but rather relies upon the following:- Interlocking doors
- Properly executed cleaning procedures
2. Dynamic Pass Box
Dynamic pass boxes are used at areas of dissimilar cleanliness classifications and are primarily used in sterilization (cleanroom) manufacturing. Dynamic pass boxes have an airflow system (including air filtration) and may include:- HEPA filters
- Airflow systems
- UV light
Key Features of Pass Boxes
The design of pass-through cabinets contains various elements that assist in successfully achieving their function.1. Inter-locking System
The most critical element is the inter-locking system. This feature ensures:- Only one door can be opened at any given time
- There is no possibility of two-way cross-contamination
2. HEPA Filtration
Dynamic pass-through cabinets use HEPA filters to remove airborne particles. This feature ensures that items entering higher classification areas do not become contaminated.3. UV Light (optional)
Some pass-through cabinets are equipped with UV lights for disinfection purposes. The use of UV light should be very carefully monitored due to its limitations and safety concerns.4. Material of Construction
Most pass-through cabinets are constructed of stainless steel to ensure:- Easy cleaning
- Resistant to corrosion
- Durability
Working Principle of Pass Boxes
Operation of a pass box is simple but highly controlled.1. Material is placed in the pass box from one side.
2. The door is closed and interlocked.
3. In dynamic pass boxes, the airflow or UV disinfection will occur after the door is closed.
4. The other side of the pass box will not be opened until the first side door has been closed securely.
5. The material can now be removed from the opposite side of the pass box.
This controlled process will keep the material in the pass box isolated from both areas at all times.
Role of Pass Boxes in Contamination Control
Pass boxes are used as a component of contamination control in the pharmaceutical industry. In particular, Pass Boxes:- Help maintain classification of the cleanroom
- Prevent microbial contamination
- Provide unidirectional flow of materials
- Reduce the need for human intervention
Placement and Design Considerations
Careful placement of pass boxes is important so that they will work efficiently. Typically, pass boxes should be installed in:- Between cleanroom grades (e.g., Grade C to Grade B)
- Between the areas where product is produced and stored
- Near the points of entry of materials
- Relative to the type of material being used - i.e., size
- Smooth internal surfaces, in order to allow for ease of cleaning
- Proper seals to prevent leakage from the pass box
- Compatible with cleanroom layout
Cleaning and Maintenance
The key to continual operation is by ensuring you clean and maintain your machine regularly. Cleaning includes:- Using approved disinfecting wipes
- Performing routine cleaning after every use
- Completing periodic deep cleanings
- Testing the interlocking system
- Checking the HEPA filter (on dynamic pass boxes)
- Verifying airflow performance
Common Problems Associated with Pass Boxes
Although pass boxes are relatively easy to operate, there are common issues that affect the operation of these units. Common problems include:- Interlocks not functioning properly, such as both doors being open simultaneously
- Improper cleaning, leading to possible contamination
- In dynamic pass boxes, filter blockage within the HEPA filters
- Improper use by the operator
Best Practices for Pass Box Usage
To be used effectively, Pass boxes must be utilized according to the best practices. The principal practices when utilizing pass boxes consist of:- Employing SOPs for material transfer
- Not opening both doors at one time
- Confirming equipment was properly cleaned before and after each time the pass box is used
- Not placing too much material in the pass box
- Training and educating personnel on the correct use of pass boxes
Regulatory Expectations
Regulatory authorities have strict expectations of pharmaceutical companies regarding contamination risk. Pass boxes must be properly designed, qualified and maintained. Some of the key expectations are as follows:- Written procedures for the use of pass boxes
- Records of cleaning and maintenance of pass boxes
- Documentation of qualification when using dynamic pass boxes
- Compliant with Good Manufacturing Practice requirements
Pass Box Qualification
Dynamic pass boxes must also be qualified to ensure they will perform according to needs. Examples of qualification tasks include:- Airflow visualization studies
- Testing the integrity of the HEPA filter
- Testing of recovery time
- Particle count monitoring
Pass boxes, which are an important tool for pharmaceutical cleanroom design, are simple but vital to maintaining contamination control by helping to ensure the safe transfer of materials between clean areas and non-clean areas.
Properly designing, utilizing and maintaining pass boxes (both static and dynamic) is important for achieving their effectiveness. Following best practices and meeting regulatory requirements will ensure that pass boxes support product quality and cleanroom integrity.
Pass boxes provide an effective barrier, to help ensure safe and compliant operations, in pharmaceutical manufacturing where even very low amounts of contamination can cause significant harm.
Is it mandatory to do particle count test on all corners of the pass box like top corners for grade a pass box?
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