How Nutsche Filter Dryers are Used in Continuous Manufacturing

July 13, 2023

Agitated Nutsche Filter Dryer

Continuous pharmaceutical manufacturing has gained significant interest due to its potential to reduce costs, energy usage, and material consumption. This innovative process also allows for the exploration of novel processing windows that would be hazardous if operated using traditional batch techniques. Continuous manufacturing technologies have been proposed or employed in the production processes of complex active pharmaceutical ingredients (APIs), with model predictive control (MPC) being applied for superior regulation of critical quality attributes (CQAs). Design space investigation and investment analyses can provide valuable insight into process design and optimisation prior to costly experimental campaigns and pilot plant studies.

Continuous drying processes are an essential part of continuous pharmaceutical manufacturing. Some examples include:

  • Semi-continuous fluid bed drying of APIs
  • Spray freeze-drying
  • Filter dryers

Advantages of Nutsche Filter Dryers in Semi-Continuous Manufacturing

Nutsche filter dryers offer several advantages in semi-continuous manufacturing processes. They combine slurry filtration, product washing, and vacuum drying processes into a single unit. Effectively, nutsche filter dryers can serve as the final step upstream of a continuous process where the product is isolated in batch form.

Agitated nutsche filter dryer technology has been used in the commercial manufacturing of advanced drugs for over 20 years, becoming the most common type of equipment for API manufacturing. This is due to its ability to combine filtering and drying with excellent containment methods, allowing for flexible discharge of wet solids, slurries, or even liquids.

Given the power of ANFDs in API processing, they clearly pose a unique opportunity for continuous manufacturing processes by providing an efficient solution for solid-liquid separation, washing, and drying within a single, contained unit, and can be integrated into continuous manufacturing lines using interconnected units or a single unit with multiple stages, enabling seamless operation and material flow. The enclosed design ensures safety and containment, minimising the risk of exposure to hazardous materials for operators and the environment. Equipped with sensors and control systems, nutsche filter dryers enable real-time monitoring and optimisation of critical process parameters, ensuring consistent product quality. The vacuum drying feature allows heat-sensitive APIs to be dried effectively at lower temperatures, reducing the risk of product degradation.

One trick to making the batch processing of an ANFD into a semi-continuous process is to double up, or add as many as four filter dryers designed to work in sequence. This enables the continuous stream to be fed into the first ANFD until it has maxed its capacity, at which point the stream feeds into the second, then third, etc. Although this isn’t a truly continuous process, the pros of ANFDs typically outweigh the cons. ANFDs have been used and validated on numerous molecules and have been integrated with ease into upstream continuous processes. This is contrary to alternative technologies, which offer a more conventional continuum but without the key features that make ANFDs so useful in product isolation.

In summary, ANFDs offer a versatile and efficient solution for solid-liquid separation, washing, and drying, making them an invaluable asset in modern pharmaceutical continuous manufacturing.

Looking for Filtration and Drying Solutions?

At Powder Systems Limited (PSL), we have been designing and engineering advanced technology to support process development for over 30 years. We are a globally recognised, award-winning business with expertise in pharmaceutical and chemical processing.

We strive to meet the ever-changing needs of our customers and partners through our commitment to providing innovative, quality products and services, in line with regulatory requirements such as ISO 9001:2015 and ATEX. Our products are ideally suited for scale-up activity and can be used for small R&D projects, pilot plant activity, and large commercial production.

We are passionate about what we do, and our innovative solutions enable pharmaceutical manufacturers to improve their processes and adopt the latest advances to produce their medicines in a safer, better, and more cost-effective way. Our technology is used every day to develop new-generation drugs benefiting millions of patients globally, and we are proud to be involved in fighting some of the greatest health issues around the world.

For more details on PSL’s Filtration and Drying solutions, click here.