Quality standard for compressed air for sterile preparations

In the production process of sterile preparations, compressed air serves as a key power source or process medium, and its quality is directly related to the sterility and safety of the product. In order to ensure that compressed air meets the production requirements of sterile preparations, strict standards need to be established from multiple dimensions such as cleanliness, microbial control, oil content, water content and system design, and run through the entire production process.

1. Cleanliness standards

The production environment of sterile preparations requires extremely high air cleanliness. As a production medium, compressed air needs to match the cleanliness of the production environment. Specific standards are as follows:

• Particulate matter control: The particle size of solid particles in compressed air must be ≤0.1 microns, and the particle concentration must be ≤0.1 mg/cubic meter. This standard ensures that compressed air does not introduce additional pollution and ensures the cleanliness of the production environment.
• number of suspended particles: In a static environment, the number of suspended particles in compressed air needs to be consistent with the production environment. For example, in Class A clean area (high-risk operating area), the number of particles ≥0.5 microns needs to be ≤3520 particles/cubic meter to maintain a sterile production environment.

2. Microbial control standards

Microbial contamination is a major risk in the production of sterile preparations, and compressed air needs to undergo strict sterilization treatment. Specific standards are as follows:

• microbial limit: The number of microorganisms in the compressed air must be ≤ 1 CFU/cubic meter (colony forming units per cubic meter). This standard is equivalent to the microbial limit level of Class A laminar air to ensure the sterility of the compressed air.
• detection method: Use a culture method or a suspended bacterial sampler for testing, and evaluate the sterility of microorganisms in compressed air samples by cultivating and counting them.
• monitoring frequency: Determine the testing cycle based on system verification results and product risks. Newly installed systems are recommended to be tested every 3 months, and mature systems can be extended to testing every 6 months to 1 year to ensure continued compliance with standards.

3. Oil content standard

Oil pollution may affect the quality of sterile preparations, and the oil content of compressed air needs to be strictly controlled. Specific standards are as follows:

• total oil content: The total oil content in the compressed air must be ≤0.01 mg/cubic meter (ISO 8573-1 Class 1 standard). In high-demand scenarios, Class 0 standards need to be met, that is, the total hydrocarbon content is ≤0.003 mg/cubic meter, to further reduce the risk of oil pollution.
• detection method: Use infrared spectroscopy or gas chromatography for testing to ensure that the oil content meets the standard.

4. Water content standard

Moisture control is crucial to preventing the growth of microorganisms and ensuring product quality. Specific standards are as follows:

• general requirements: The dew point of compressed air needs to be ≤-40℃ (corresponding to a water content of about 0.11 g/cubic meter) to ensure that the air is dry and reduce the risk of microbial growth.
• Highly demanding scenarios: In highly demanding scenarios such as sterile preparations, the dew point needs to be ≤-70℃ (corresponding to a water content of about 0.003 g/cubic meter) to provide drier compressed air to meet the needs of sterile production.

5. System design and material standards

In order to ensure the quality of compressed air, system design and material selection must meet the following requirements:

• material selection: It is recommended to use stainless steel of 304 and above for storage tanks, pipelines and valves to resist corrosion and reduce the release of impurities.
• welding process: Argon arc welding method is recommended for pipeline welding to ensure that the weld is smooth and free of impurities and reduce the risk of pollution.
• filtration system: Configure a multi-stage filtration system, including pre-filter (such as 5 microns, 3 microns), precision filter (such as 1 micron, 0.1 micron, 0.01 micron) and terminal sterilization filter (such as 0.22 micron) to gradually remove particulate matter, oil and microorganisms.

6. Environmental control standards

The production environment has a direct impact on the quality of compressed air, and environmental control needs to be strengthened:

• climate control: The relative humidity needs to be controlled between 40% and 60%, and the temperature is usually controlled between 18 and 26 ° C to maintain a stable production environment and reduce the growth of microorganisms.
• cleaning and disinfection: Keep the workshop clean and dry, and regularly clean and disinfect the compressed air system to prevent the growth and spread of microorganisms.
• People and goods management: Control the flow of people and the entry and exit of articles to prevent external microorganisms from being brought into the workshop and polluting the compressed air system.

VII. Monitoring and maintenance standards

In order to ensure that the quality of compressed air continues to meet standards, a strict monitoring and maintenance system needs to be established:

• regular testing: Regularly test the quality of compressed air, including particulate matter, microorganisms, oil content, water content and other indicators to ensure continuous compliance with standards.
• equipment maintenance: Regularly replace the filter, clean and disinfect the system, and keep the equipment in good condition. At the same time, detailed maintenance records are maintained to track system performance and maintenance history.
• emergency plan: Develop emergency plans to deal with compressed air system failures or pollution incidents to ensure that measures can be taken quickly to protect product quality in emergencies.

The quality standards for compressed air for sterile preparations cover many aspects such as cleanliness, microbial control, oil content, water content, system design, environmental control, and monitoring and maintenance. By fully meeting these standards, the quality and safety of compressed air used for the production of sterile preparations can be ensured, providing a strong guarantee for the production of sterile preparations.