Compressors for drug manufacturing in pharmaceutical industry

Did you know Indian pharmaceutical industry is 3rd largest industry in the world in terms of production volume and contribute around 2% to the country’s GDP. India pharma sector is also the largest provider of generic drugs globally and thus plays an important role in the global pharma sector. India’s pharma exports mainly consist of drug formulations and biological up to 77% followed by Bulk drugs and intermediates up to 21%. (Data Source: Annual report 2019-20 by Dept of Pharma, GoI). The pharmaceutical manufacturing operations may be categorized as basic production of bulk drug substances (API manufacture) and Drug formulations with the help of API in the various dosage forms. The solid drug manufacturing can be further split into series of different processes like milling, granulation, coating, tablet pressing, and others wherein compressed air also plays an important role.

The compressed air is a vital utility driving the below processes for the drug manufacturing.

• Milling
• Mixing
• Granulation
• Drying
• Pressing
• Coating
• Packaging

Hence efficiency and risk mitigation in generation of this utility gives manufacturers a lot of operational excellence. Now, what if the compressed air used in above processes is contaminated with oil & water? Most of the manufactures perceive contamination as a major risk which costs huge money and time due to product rejections of bulk drug. This risk is now regulated by the US FDA by issuing guidelines under Current Good Manufacturing Process(cGMP). The highest consumption of compressed air is at milling process which is critical to produce ultra-fine powder for the tablets and capsules. This process is mainly done by a jet mill/microniser which grinds materials by using a high-speed jet of compressed air or inert gas (preferably Nitrogen) to impact particles into each other. The jet mill utilizes compressed air grind and classify, in a single chamber with no moving parts. Activated by high pressure air, the particles are accelerated into a high-speed rotation in a shallow grinding chamber. As the particles impact on one another their size is reduced. The final particle size is controlled by varying the rate of the feed and compressed air pressure. So, while choosing the right utility equipment i.e. compressor, following points to be considered:

1. Right pressure of compressed air. Higher the pressure, more effective the process.
2. Air quality in terms of moisture and oil
3. Availability of equipment.

The typical solutions available in market for the said process is either choosing water-injected screws which can deliver up-to 13 bar or oil-free screws up-to 10 bar. The option of oil-injected screw compressors is also chosen in this market which has high risk of oil contamination and maintenance of filters. Oil-injected solution ought to be used in non-contact and auxillary requirements but not for the jet milling in pharmaceutical as per the industry experts.

Henceforth, the best and strongly recommended solution is to have Class 0 oil-free compressed air in the pharma process which is in line with guidelines of current Good Manufacturing Process(cGMP) issued by US FDA. Additionally, jet milling is a batch process, making the requirement of compressed air intermittent. Therefore, a variable frequency drive/variable speed drive (VSD) oil-free compressor is the best foot forward to meet this critical requirement.