Neil Pizzey, managing director, Amazon Filters says containment, catalyst capture and decolourisation are vital aspects of pharmaceuticals production but all require robust, effective filtration to ensure process optimisation.
Amazon Filters
From medicines in the treatment of cancer and autoimmune diseases to drugs that help combat hypertension, epilepsy and asthma, catalysts are critical to active pharmaceutical ingredient (API) manufacturing.
Once a catalyst has synthesised the required chemical reaction and is no longer needed, the task is to remove it from the fluid stream and arrange disposal or recycling.
From both the environmental and cost control perspectives, it is prudent to implement strategies to reclaim as much as possible of a catalyst’s rare metals such as palladium, platinum, rhodium or ruthenium.
Catalyst capture
As more pharmaceutical companies commit to sustainable production practices, the focus on reclaiming such metals will grow.
The challenge is to decide how best to isolate and remove the catalyst from the process while minimising or eliminating operator exposure.
Traditional methods for recovering spent catalysts include manual plate filters, filter presses, bags and lenticular cell filters.
Process filter manufacturer Amazon Filters works closely with a number of producers engaged in safe, efficient catalyst capture.
In a recent example from Spain with a multinational pharmaceutical customer, Amazon Filters was called on to help remove a palladium-on-carbon catalyst that was supplied wet and then mixed with methanol for use in the reaction vessel.
The customer had tended to use filter bags for capture but it was acknowledged that the necessary filter change-outs were increasing the risk of operator exposure and making subsequent re-packaging for off-site processing complicated.
To address the issue, the customer agreed to trial a specially modified version of Amazon Filters’ SupaClean system.
With this, filters are contained inside a secure bag assembly for isolation and an outer stainless-steel housing that provides the necessary pressure vessel for the filtration process.
In the Spanish example, the modifications involved placing seven off 20” SupaSpun II filters in a 30” long SupaClean housing.
As well as simplifying the onward handling and transportation of the catalyst for subsequent recovery of the valuable palladium, the additional free volume made available through the system allowed up to 3kg of concentrated catalyst slurry to be retained.
And there were a number of other advantages identified in the trial which have either been put into ongoing operation or cited as potential benefits for other operators:
- After filtration of the catalyst slurry, low pressure compressed nitrogen is introduced via the integral tapping on the side of the housing. This collapses the internal flexible containment bag and purges out residual carrier solvent.
- The filter inlet and outlet connections are capped off securely, ensuring the catalyst remains 'wet' in the filter to prevent any risk of spontaneous ignition or combustion.
- A customised 'cradle' allows the housing to pivot to further improve safety with respect to manual handling.
- The system ensures the required filtration efficiencies can be matched to the particular catalyst particle size.
- The flexible bag is available in various materials to ensure chemical compatibility.
Feedback from the Spanish facility and other pharmaceuticals customers seeking to recover rare metals from catalysts is that the SupaClean format supports health and safety practices by minimising operator exposure. The robust filter technology means the equipment has a longer lifespan, requires fewer changeouts and periods of downtime and is highly cost-efficient as part of OPEX.
Decolourisation
The traditional approach to achieving decolourisation in API manufacturing has been to add loose activated carbon directly to reactors, carbon-impregnated lenticular cell filters or carbon block filters. The choice depends on legacy processes, historical carbon grades and batch volumes.
During the development and scale-up of a new API in a kilo laboratory, a manufacturer came to Amazon Filters requesting a more efficient and safer decolourisation solution. While lenticular cell filters are commonly used at this scale, discussions with the site process engineer identified an opportunity to improve efficiency, reduce waste and enhance operator safety by switching to a sintered carbon block format.
Made from a blend of granular and powdered activated carbon, the SupaCarb CP carbon block filter offers high-colour removal efficiency and throughput. An integral prefilter layer extends carbon life, while the sintered, resin-bonded structure eliminates the risk of carbon shedding downstream.
In this application, an 8" diameter lenticular cell was replaced with a standard 2.5" diameter SupaCarb CP cartridge. Despite its smaller size, the cartridge delivered superior colour removal due to the significantly higher carbon density compared to carbon-impregnated cellulose media.
Additional benefits included a reduced footprint, lower consumable waste, compatibility with standard cartridge housings, and improved health and safety through installation in a SupaClean enclosed format.
The system was designed at a flow rate of 0.8 L/min per 10" carbon block, making it well suited to kilo-lab batch sizes. Following successful laboratory trials, the technology was also implemented at production scale to replace loose granular carbon. The production system now processes 1 m³/hr of API using two parallel multi-round housings, each containing five 30" SupaCarb CP cartridges. Decolourisation is achieved in a single pass, compared to multiple passes previously required with loose carbon.
To summarise the benefits here, the sintered carbon block technologies proved to be more cost-effective, efficient and safer compared with traditional API decolourisation methods.
Containment
A multinational pharmaceutical and biotechnology company required support to design and manufacture 100 bespoke filter housings capable of processing both gases and liquids during sensitive API production.
The housings needed to be manufactured in 316L stainless steel and Hastelloy C22, with material selection carefully matched to aggressive solvents and gases to ensure long-term compatibility and operator safety.
The Singapore-based client had specific design and health-and-safety requirements that could not be met using standard, off-the-shelf housings.
While a global engineering contractor managed the overall project delivery, filtration was recognised as a critical process step requiring specialist expertise. Basic specifications alone were insufficient to address the complexity of the application.
The project involved a multi-tiered supply chain spanning Asia and Europe, requiring clear communication and a knowledgeable distribution partner.
Having previously worked with the client, Amazon Filters had a strong understanding of the process and direct access to the client’s engineering team, enabling efficient collaboration.
Bespoke housings were designed to integrate seamlessly with the client’s existing installation, including fully welded vents and drains. The final solution comprised ATEX-approved, explosion-safe housings designed to minimise static, spark risk and operator exposure to hazardous chemicals.
By finalising the housing design early and managing manufacture in-house, the project was delivered efficiently, reducing costs, simplifying installation and providing a robust, long-life filtration solution tailored precisely to the client’s process.