Compressed Air in the Pharmaceutical Industry
Very stringent hygiene standards are specified for production conditions for manufacturing medicinal products, particularly for clean room conditions. It is therefore very important that the production takes place in an environment that is free of germs, particles, bacteria and contaminating oils. The compressed air utilised is also therefore subjected to high requirements because it often comes into direct contact with the product itself in the production processes of the pharmaceutical industry. Depending on its application, compressed air must be sterile or oil-free, for example. To meet the obligation of proof e.g. for auditors, continual monitoring (24/7) is necessary for compressed air with product contact.
There are various regulations, such as GMP, FDA and the European Pharmacopoeia, but these do not define compressed air quality classes for individual applications. One exception to this general rule is the compressed air used as breathing air; you can find out more about this through our information about medical technology.
This means that every pharmaceutical company must specify for itself which compressed air quality in accordance with DIN ISO 8573-1 is required for its production process. We will be happy to assist you with specifying the quality class and the suitable design of your compressed air treatment in order to keep to the required compressed air class constantly and make a contribution to your process reliability.
Applications in the pharmaceutical industry
Compressed air is required for the tablet manufacturing process and this compressed air often also comes into direct contact with the product. This direct product contact occurs after the tablet press where compressed air is utilised to remove dust particles or faulty products are sorted out. Oil-free and dry air is important here otherwise, for example, the pressed tablets could swell up. Compressed air can also be used for applying lubricants onto the tablet press so that the tablets can be ejected easier.
Compressed air is already utilised at the initial stages for mixing the powder mixture and/or the production of the granules for the tablet press. The stages after the presses, the so-called coating, i.e. the coating and/or the encapsulation also utilise compressed air. A common method is the fluidised bed process whereby an air flow ensures that the tablets hover and are constantly in motion. They are sprayed, evenly moistened and dried by utilising spray nozzles. Here and in further processes, the compressed air serves as atomising air and is considered a process aid, which means accordingly high requirements are made on its purity.
Typical problems in the manufacture of tablets – in addition to the health risks for the consumer – are blistering, cracks or breaks in tablets or colour variations. Moist and oil-contaminated compressed air can be one reason for this.
Cleaning and drying
It is not only the machines that need cleaning; the vials, ampoules and bottles into which the medicinal product is filled also have to be especially clean. The CIP cleaning process (Clean In Place) has been established for cleaning of plants, systems and containers. Compressed air is utilised here for drying. Dry ice blasting is an addition method for cleaning. The dry ice impacts on the surface to be cleaned and loosens deposits. The loosened deposits are then blown off with compressed air.
The filter in the fluidised bed plants must be cleaned during production. This can be executed via a filter blow-out system. Material residues will therefore be routed back into the process with compressed air. There is also a direct product contact here whereby high requirements for the quality of the compressed air must be achieved.
Another application is the cleaning of vials, bottles and ampoules: In this case, the compressed air is also used for drying the vessels and removing any final particles. This often takes place in the clean room.
Compressed air is often also utilised in the pharmaceutical industry for transporting integral elements for the production process e.g. bulk solids, liquids, powders and granules. Pneumatic conveying can be executed via compressed air or under vacuum.
When conveying takes place under pressure, the compressed air is generated and routed to a mixing head. There, it picks up the powder and conveys this to the required location. During this type of pneumatic conveying, the substances transported come into direct contact with the compressed air. This method is used for emptying silo vehicles and for distributing substances in production.
The finished products, such as tablets and capsules, are also transported back and forth between the individual processing units with compressed air. Transporting with compressed air prevents damage to the medicinal products, but a consistent quality of the compressed air is therefore required. In accordance with DIN ISO 8573-1, the German VDMA recommends a compressed air quality of sterile 1: 3: 1 for transporting raw materials and finished products.
Medicinal product packaging
Compressed air is used on packaging plants and systems e.g. for transporting products and packaging or for packing the product and for sealing the packaging. A controlled atmosphere will be created around the product with highly hygroscopic (water attracting) products, such as e.g. pharmaceuticals. Very dry compressed air must be present (inflating bags etc.), especially at packing positions when packaging pharmaceuticals.
There is often centralised compressed air processing, therefore the compressed air must be transported to the application location. It is possible that the compressed air is supplemented with water again on this route. Hygroscopic substances react with the moisture from the ambient air. In order to ensure the product quality, contact of the humidity with the product must be prevented. For this reason, an additional compressed-air drying is required directly on the packaging machine.
If active ingredients are filled in ampoules and vials and then sealed, a sterile environment is even required.
Regulating valve and cylinder
Compressed air is utilised as the control air in the pharmaceutical industry for regulating production plants and systems e.g. via a regulating valve and cylinder. Lower requirements are normally valid for the control air as it does not come into direct contact with the product. There are however exceptions: The control air is subjected to special requirements in clean rooms. This also applies if the control air could affect the process.
When the compressed air does not comply with requirements, then malfunctions of pneumatic tools and machines can occur, lead to corrosion in pipework, cylinders and other components as well as freezing in exposed services during cold weather. This creates a threat of increased downtimes as well as maintenance costs for pneumatic machines, tools and control systems. The correct compressed air processing and treatment as well as periodic monitoring and maintenance is therefore essential.
The production of medicinal products takes place partly in clean rooms, and some of the production steps there require compressed air. Compressed air can be used in all clean room classes. It can occur as an energy carrier in motors and pumps, for example. In these cases, the compressed air used does not come into contact with the product, but it must comply with the quality of the ambient air into which it is released. In other words: the compressed air should correspond at least to the air quality of the respective clean room class into which it is released. The requirements are worded in quite concrete terms in the “FDA Guidances for Industry: Sterile Drug Products Produced by Aseptic Processing — Current Good Manufacturing Practice”.
In the case of clean room applications, compressed air is used for drying the washed primary vessels, before filling with the product as well as for filling liquids in accordance with the blow-fill-seal method. It is important that no germs and particles are contained in the compressed air.