1. Brief Introduction to the Dispensing Room

The dispensing room is a specific functional area in pharmaceutical cleanrooms, where operators perform the tasks of subdividing, weighing, and dispensing drugs, raw materials, or intermediates for subsequent production stages.

In the GMP production chain, the dispensing room plays an important role because:

• It is the intermediate point between the warehouse of raw materials and the production areas, where cross-contamination may occur if not properly designed.
• Operations in the dispensing room are directly related to the accuracy of dosage, which affects the quality of the final product.
• Personnel working in this environment need to be protected from exposure to drug dust or chemicals, while product safety must still be ensured.

In other words, the dispensing room acts as a "double shield": protecting both the drug and the patient, as well as the operators. Therefore, any design errors in this area may lead to serious risks regarding product quality and GMP compliance.

2. Common Mistakes in Designing Dispensing Rooms

During the design of dispensing rooms, many pharmaceutical plants often make mistakes that directly affect product quality, operator safety, and the ability to achieve GMP certification. Below are the most common issues:

Improper Layout Without One-Way Flow

• Personnel and materials share the same path, leading to a risk of cross-contamination between raw materials and finished products.
• Lack of clear zoning between airlock - dispensing room - clean corridor, making hygiene control difficult.
• Consequence: Dust and microorganisms can easily spread, affecting pharmaceutical quality.

Lack of Pressure Differential Control

• Failure to maintain positive pressure in the dispensing room, causing contaminated air from corridors to flow in.
• No installation or insufficient number of differential pressure gauges, making continuous monitoring difficult.
• Consequence: Loss of environmental control, non-compliance with ISO 14644 and EU/WHO GMP standards.

Non-Compliant Air Filtration System

• HEPA filters are incorrectly installed, failing to create unidirectional airflow.
• Airflow does not meet the required air changes per hour according to GMP.
• Consequence: Increased risk of dust and microbial contamination in the dispensing room; difficulties in passing quality audits.

Design Not Considering Practical Operations

• Pass Box placed in inconvenient locations, forcing operators to move unnecessarily and increasing contamination risk.
• Dispensing tables and storage cabinets not designed according to ergonomic standards, making operations difficult and error-prone.
• Consequence: Reduced work efficiency, higher risk of accidents and operational errors.

Inappropriate Finishing Materials

• Floors, walls, and ceilings made from materials that generate dust or are difficult to clean, such as ceramic tiles or regular paint.
• Uneven surfaces with many gaps, making cleaning and disinfection difficult.
• Consequence: Failure to meet GMP inspection requirements, resulting in audit non-compliance.

3. Solutions and Recommendations for Proper Design

To ensure that the dispensing room meets GMP standards and maintains a stable clean environment, the following solutions should be applied:

Clear and Separate Flow of Personnel and Materials

• Design one-way flow: personnel enter through airlocks, while materials enter through Pass Boxes.
• Use interlock doors to prevent simultaneous opening and minimize the entry of contaminated air.
• Clearly separate paths for personnel and raw materials to reduce cross-contamination risks.

Use of FFU/HEPA Box Compliant with ISO 14644

• Equip with HEPA filters H13 or H14, correctly installed to create unidirectional airflow in the dispensing area.
• Apply FFU (Fan Filter Units) to maintain stable airflow and allow easy replacement during maintenance.
• Ensure air changes per hour meet GMP standards: at least 20 ACH for dispensing rooms.

Maintaining Pressure Differential with 2-Needle Differential Pressure Gauges

• Install 2-needle differential pressure gauges at each entry door to monitor the pressure difference between the dispensing room and corridors.
• Set warning limits (e.g., ≥ 10-15 Pa) to quickly detect system imbalance.
• Combine with electronic pressure sensors connected to a central monitoring system for GMP audit compliance.

Selection of Flat, Dust-Resistant Panel Materials

• Use sandwich panels with flat surfaces, coated steel panels, or stainless steel for easy cleaning and dust resistance.
• Floors should be coated with antistatic epoxy or seamless vinyl to avoid joints and cracks.
• Ceilings should be flat and easy to remove for convenient air filtration system maintenance.

Proper Integration of Pass Box, Interlock, and Air Shower

• Pass Boxes should be placed at convenient locations for transferring materials without affecting personnel flow.
• Interlock doors should be installed in airlocks to control airflow and reduce cross-contamination.
• Air Showers should be placed before the dispensing room to minimize dust carried by personnel.

By implementing these solutions, dispensing rooms will not only comply with GMP but also enhance safety, operational efficiency, and long-term quality control.

4. Quick Checklist for Designing a Dispensing Room

The table below summarizes the key technical requirements to consider when designing a dispensing room, ensuring compliance with GMP and ISO 14644:

Practical application: When implemented, this checklist can be used as an internal SOP document, helping engineers, QA/QC teams, and design contractors maintain strict control from the very beginning of the project.

5. Frequently Asked Questions

Why must the dispensing room maintain positive pressure?

Positive pressure ensures that clean air in the dispensing room always flows outward, preventing dust and microorganisms from corridors or dirty areas from entering. This is a mandatory requirement to avoid cross-contamination and ensure GMP compliance.

What type of Pass Box should be used in a pharmaceutical dispensing area?

For dispensing rooms, it is recommended to use an electronic Pass Box with interlock. This equipment ensures safe door operation, prevents air leakage, and reduces the risk of cross-contamination during the transfer of raw materials or items.

Is it mandatory to use HEPA H13 filters?

According to GMP, the minimum filtration requirement is HEPA H13. However, many pharmaceutical plants choose HEPA H14 to enhance fine particle and microbial filtration, ensuring a more stable clean zone, especially in sensitive areas like dispensing rooms.

What is the difference between a dispensing room and a weighing room?

• Weighing room: Focuses on protecting operators from pharmaceutical dust released during weighing, while maintaining raw material accuracy.
• Dispensing room: Focuses on controlling cross-contamination between different drugs during subdivision and transfer to production areas.

6. Contact VCR for Consultation and Support

Are you planning to design or renovate a dispensing room for your pharmaceutical plant?

Let VCR Cleanroom Equipment support you with:

• Complete solutions with compliant equipment: Pass Box, Interlock, FFU, Differential Pressure Gauges, Cleanroom Panels.
• End-to-end support from design - construction - validation, ensuring your facility can easily pass GMP audits.

Hotline: 090.123.9008

Email: [email protected]

Website: https://phongsachyte.com/

Diep VCR