Understanding Airlock Systems in Pharma Industry

An airlock system is an enclosed area that acts as a transitional zone between two distinct environments, with different levels of cleanliness or pressure.

Drug Medicine Pharma manufacturing Factory Industry Unit
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SDCO Cum Licensing Authority |
Food and Drugs Administration, (FDA) Haryana, India. |
Email ID: dahiya19@yahoo.com
Rakesh Dahiya

Last Updated on December 31, 2023 by The Health Master


Airlock systems play a vital role in maintaining controlled environments and preventing cross-contamination in various manufacturing processes.

In this article, we will explore the Concept of airlock systems, types of airlocks, such as sink, bubble, and cascade airlocks, and discuss their applications in sterile manufacturing and OSD manufacturing.

Additionally, we will touch upon the comparison between MAL (Material Airlock) and PAL (Personnel Airlock) systems, and finally, we will examine the purpose and significance of airlock systems.

What is an Airlock System?

An airlock system is an enclosed area or chamber that acts as a transitional zone between two distinct environments, typically with different levels of cleanliness or pressure.

Its purpose is to control the flow of personnel, equipment, and materials while minimizing the transfer of contaminants, pollutants, or unwanted particles.

Types of Airlocks:

Sink Airlocks:

Sink airlocks are designed to maintain a unidirectional airflow, directing air from the cleaner area to the less clean area.

They are commonly used in pharmaceutical manufacturing facilities to prevent the entry of contaminants and maintain the sterility of the production environment.

In sink airlock, the pressure inside airlock is negative and in adjacent areas pressure is positive so air moves from higher pressure area to lower pressure area mean from adjacent rooms to the airlock.

Bubble Airlocks:

Bubble airlocks function similarly to sink airlocks, but with an added visual indicator.

They employ a transparent or translucent wall that allows personnel to visually confirm if the airlock is under positive or negative pressure, ensuring proper airflow and contamination control.

In bubble airlock pressure inside the airlock is high or positive and in adjacent sides, the pressure is less or negative.

Cascade Airlocks:

Cascade airlocks are utilized in situations where there are multiple rooms or areas with varying levels of cleanliness.

These airlocks maintain a controlled pressure gradient, preventing the migration of contaminants between the different spaces.

In cascade airlock system pressure increases or decreases in ascending or descending order.

Airlocks in Sterile Manufacturing and OSD Manufacturing:

Sterile Manufacturing Airlocks:

In sterile manufacturing, where maintaining a sterile environment is crucial, specialized airlocks called sterile manufacturing airlocks are employed.

These airlocks are designed with advanced filtration systems and stringent controls to ensure the integrity and sterility of the manufacturing process.

OSD (Oral Solid Dosage) Manufacturing Airlocks:

OSD manufacturing airlocks are specifically tailored for the production of oral solid dosage forms, such as tablets and capsules. These airlocks facilitate the transfer of materials, equipment, and personnel while minimizing the risk of cross-contamination and ensuring product quality.

Comparison: MAL vs. PAL:

Material Airlock (MAL) and Personnel Airlock (PAL) are two distinct types of airlocks with specific functions:

Material Airlock (MAL):

MALs are primarily used for the transfer of materials, components, and equipment between different cleanroom areas, ensuring minimal contamination risks.

Personnel Airlock (PAL):

PALs are designed to control the movement of personnel between different areas with varying levels of cleanliness, preventing the introduction of contaminants into critical zones.

Purpose of an Airlock:

Airlock systems serve several key purposes, including:

  • Contamination Control: Airlocks prevent the ingress and egress of contaminants, maintaining clean environments and preserving product integrity.
  • Pressure and Airflow Management: They enable the management of pressure differentials and airflow direction, ensuring controlled environments and preventing cross-contamination.
  • Regulatory Compliance: Airlocks play a crucial role in meeting regulatory requirements and industry standards for cleanliness and safety.
  • Personnel and Material Transfer: Airlocks facilitate the movement of personnel, materials, and equipment while minimizing the risk of contamination.


Airlock systems are integral to various manufacturing processes, providing an effective barrier against contaminants and cross-contamination.

Understanding the different types of airlocks, their applications in sterile and OSD manufacturing, as well as the distinction between MALs and PALs, is essential for maintaining product quality, safety, and regulatory compliance.

By implementing appropriate airlock systems, manufacturers can ensure controlled environments and protect the integrity of their production processes.

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