Acting as reagents, leak-finders, process gases and carriers for chromatography; high-purity gases are absolutely vital throughout the pharmaceutical supply chain. In this article, we take a look at the most common pharmaceutical gases and see how they’re put to use in the pharmaceutical industry.
Besides air, nitrogen (N2) is the most commonly-used gas in the pharmaceutical industry.1 There are two reasons for this. First, nitrogen is the major constituent of our atmosphere, so it’s highly abundant. Second, nitrogen is chemically inert.
These properties make nitrogen something of a workhorse in the pharmaceutical industry, where it’s commonly used for blanketing, purging, pressurising and mixing.
Because it is unreactive, nitrogen is used to shield sensitive precursors, reagents or pharmaceutical products and prevent them from reacting with oxygen in the air. Notably, nitrogen is used as a packaging gas, used to protect drugs from degradation in blister packs and in sterile form-fill-seal (FFS) vials.2
As a pressurising agent, nitrogen is used to test process equipment (such as tanks, vessels and pipelines) for leaks. In a similar capacity, nitrogen is also used to dispense or transfer other fluids from storage tanks and reservoirs.
Finally, nitrogen is commonly used as a carrier gas in gas chromatography.3 In chromatography applications, purity of the nitrogen carrier gas is critical: any impurities are likely to be detected during analysis. Using ultra-high purity nitrogen gas lowers the effective noise floor of the chromatographic analysis, enabling more accurate detection of impurities in pharmaceutical products.
Oxygen (O2) is an important reagent in pharmaceutical synthesis. Arguably one of the greenest oxidising agents available to an organic chemist, oxygen is typically deployed in the form of “synthetic air”: a mixture of around 10% oxygen with nitrogen to avoid the combustion risk associated with pure oxygen.4
Oxygen is also used in biopharmaceutical applications, where cell cultures are used to produce pharmaceutical compounds in fermenters. Often, ambient oxygen concentrations are not optimal for use in bioreactors, so pure oxygen is used to “enrich” the internal atmosphere, accelerating growth rates and increasing productivity.
Like nitrogen, carbon dioxide (CO2) is inert. This makes it suitable for general-purpose blanketing and packaging applications. But carbon dioxide also performs important functions during pharmaceutical synthesis.
Carbon dioxide is used in the pharmaceutical industry in the form of a supercritical fluid. At high temperatures and relatively low pressures, fluids can exist in an intermediate state between liquid and gas, known as supercritical fluid. Carbon dioxide is the most commonly used supercritical fluid in the pharmaceutical industry, and plays a crucial role in the extraction of organic compounds.5,6 In this form, carbon dioxide is also used for “micronisation” – the production of very small particles of active pharmaceutical ingredients.7
Pharmaceutical-grade Gases from Air Products
In the pharmaceutical industry, purity is critical at every stage. Impurities in pharmaceutical gases – such as water vapour or reactive species – run the risk of reacting with sensitive precursors or pharmaceutical products. These spurious reactions can affect yields, accelerate the degradation of products, and create inaccuracy in analytical processes. The purity of pharmaceutical products is of paramount importance, and this can only be reliably achieved when using highly pure process gases.
For any pharmaceutical business, it’s crucial to find a trustworthy gas supplier that can support with all aspects of gas use. Air Products is proud to be a leading supplier of ultra-high-purity gases to the pharmaceutical industry. We form strong relationships with our pharmaceutical customers, supporting their growth with a range of different supply modes to suit their requirements.
We provide nitrogen, oxygen and carbon dioxide at pharmaceutical-grade purity; produced, analysed, stored and distributed in full compliance with regulatory standards. Our pharmaceutical gases are prepared to ultra-high purities exceeding those specified by the European Pharmacopeia and Good Manufacturing Practice (GMP), Part II, as well as Japanese and US Pharmacopeia.
References and Further Reading