Meeting Growing API and CDMO Production Demands with Dust Collection Systems

As global production of active pharmaceutical ingredients (APIs) expands, the significance of well-designed dust collection/containment systems has never been more critical in protecting oral solid dose (OSD) manufacturing. Because dust collection systems vary widely, they must be selected and configured according to the specific dust type and application. This article offers recommendations and tips for selecting dust collection systems for pharmaceutical process dust.

Global Estimates of API Growth

According to Grand View Research, the global market for APIs was valued at $237.47 billion in 2023 and is projected to increase at a compound annual growth rate (CAGR) of 5.75% from 2024 to 2030. Factors propelling this growth include technological improvements in API production, biopharmaceutical production increases, and a rising elderly population. Likewise, the escalating occurrences of cardiovascular, genetic, and neurological conditions, infectious diseases, and hospital-acquired infections are expected to significantly propel market growth.¹

The generic API segment is also expected to show rapid expansion over the forecast period with hundreds of patents set to expire by 2030. Additionally, the market for over-the-counter (OTC) products is poised to grow due to widespread availability and particular emphasis on preventive health items, including health supplements, nutraceuticals, and probiotics.

In addition, there is an increasing focus on ensuring the security of clinical product supply to support clinical studies. Emerging biotech R&D must conduct clinical trials domestically when research is funded by U.S. sources. As a result, these companies seek manufacturing partners that can provide domestic API production. Plus, the substantial growth of innovators and contract development and manufacturing organizations (CDMOs) in North America is anticipated to boost the need for API production and commercialization.

APIs in OSD Production and the Importance of Dust Collection

OSD manufacturing involves critical processes that demand stringent control over airborne contaminants. Dust collectors play a pivotal role in maintaining product quality, employee safety, and regulatory compliance in applications such as: 

• Blending and granulation processes that generate dust during material mixing and granule formation 
• Fluid-bed drying and spray drying processes that involve turning liquid formulations into powders 
• Tablet compaction and coating processes that generate fine particulate matter during tablet production

Dust collection systems work as a physical barrier between the API material and the surrounding environment. By capturing airborne particles, they minimize cross-contamination risks in the same facility.

Therefore, dust collection systems also help to facilitate compliance with the FDA’s current Good Manufacturing Practices (cGMP), which mandate strict adherence to quality standards. It is important for facility operators to fully document procedures to ensure transparency and traceability. This includes maintenance schedules, filter replacements, and safety protocols.

In addition, properly designed dust collection systems mitigate explosion risk due to dust accumulation and include protection features to reduce risk to processes, people, and facilities.

OSD Dust Characteristics

When selecting dust collection for pharmaceutical processes, seek a manufacturer with specific filtration experience and dust testing capabilities. Since no process dust is the same, select a partner who has knowledge and first-hand experience with a variety of pharmaceutical-specific processes as well as cutting-edge lab facilities to handle and test dust samples. Find a partner who can provide complete full-scale dust analysis, clear feedback, and thorough documentation to help you best understand how to handle your process dust. Pharmaceutical dust differs from all other process materials due to the addition of APIs and the growing use of solvents that require additional layers of protection.

Designing an Effective Dust Collection System for OSD Production

A dust collector paired with OSD production equipment plays a crucial role in ensuring dependable and safe operation. However, like many other applications, when the collector does not meet specific process needs or is not sized correctly, it can negatively impact performance, resulting in higher operating costs, increased filter usage, and additional maintenance downtime leading to higher production costs.

The following are areas of dust collection that should be carefully selected during the design phase.

Capture and Conveyance

The objective of capturing and conveying dust is to maximize efficiency from the pickup point to the inlet of the collector. This begins with an effective hood design to capture the dust without pulling in excessive ambient air. Likewise, efficient duct designs maintain and manage efficient conveying velocities, limit increased static pressure, and reduce dust drop-out during conveyance to the collector.

We recommend following the guidelines provided in ACGIH’s Industrial Ventilation: A Manual of Recommended Practice for Design (www.acgih.org) along with working with experienced dust collector manufacturing representatives who can design efficient systems from pick-up points to exhaust to atmosphere.

Dust Collector Orientation and Design

The dust collector should be viewed as more than simply a housing for the filters. When paired with good capture and conveyance, correct filter orientation, and efficient design, the system will reduce overall energy costs, allow filters to last longer, and reduce downtime costs.

Pharmaceutical dust is considered “light and fluffy,” and with the wrong collector and/or filter orientation it can become difficult to remove from the hopper. Horizontally oriented filters tend to use a high air inlet that accelerates air and dust as they enter the collector. This accelerated air will often immediately load the top layer of filters, reducing the total filtration area, and may even abrade the cartridges, wearing them out faster. Top air inlets can also cause a hopper-sweep that suspends fine dust within the filter area and prevents dust from dropping into the hopper. Continuously re-entraining dust into the filters requires more compressed air for cleaning as well as a higher pressure drop, leading to more energy expended on the blower.

When filtering OSD dust, it has been proven that a low, side inlet paired with vertically oriented filters is more effective in slowing airspeed, channeling this dust away from direct impact with filters, and providing easier dust drop-out into the hopper. These performance benefits help to maintain lower pressure drop (an indicator of airflow resistance), which equates to longer filter life and reduced operating costs.

Primary Filtration Media

Choosing the right primary filter media is vital for each specific application and should be based on factors like dust characteristics, particle size, loading, and spread.

There are two basic varieties of filter media used in dry dust collection: a nonwoven blend known as cellulose and a synthetic polyester or a polyester-silicone blend known as spunbond.

The more economical option is cellulose, typically comprising a mix of 80% cellulose and 20% synthetic fibers. This media is suitable for a broad range of dry powder uses and can withstand relatively high operational temperatures. On the other hand, spun-bond media is made entirely of synthetic fibers, enabling it to endure aqueous or solvent-based and higher-temperature processes. Its robustness and ability to maintain integrity when exposed to moisture during production make it a reliable choice.

Both types of media can be treated to enhance their functionality, such as increasing static dissipation, fire resistance, moisture repellency, and nanoparticle capture.

Filter efficiencies are not only based on filter material. Cartridge construction also plays a role in filtration efficiency and lifespan. Cartridges should contain broad and even pleats that maintain an unobstructed airflow and allow accumulated dust to dislodge and fall into the hopper during the system’s pulse-cleaning cycle. Conversely, when filter media pleats are densely packed, air cannot move through efficiently, nor can the dust collector’s reverse pulse cleaning mechanism dislodge the dust trapped between the pleats. This leads to increased airflow resistance, higher energy costs, and diminished filter lifespan.

Integrated HEPA or separate after-filter housings are often recommended to serve as a secondary safeguard for the dust collection unit and to facilitate the safe discharge of filtered air to the outside.

Dust Containment

OSD manufacturing sites handling dangerous dust should undertake a risk-based assessment to identify the appropriate containment strategies. Generally, a degree of isolation and containment is necessary, given that releasing dust near the process or workspace is not an option during routine collector maintenance.

Means to contain these biologics include bag-in/bag-out (BIBO) systems for filter changes and secured liner systems for hopper discharge. Both of these systems, when well-designed and fully surrogate tested, protect employees from exposure and adjacent processes from cross-contamination.

Surrogate testing uses a substitute material that simulates an API, enabling manufacturers to assess the efficacy of isolation and containment systems and forecast their performance during actual production. This approach replicates the conditions of the actual work environment or worst-case scenario as accurately as possible, without incurring the costs or health risks associated with managing the genuine API.

Surrogate testing is commonly performed under the supervision of a manufacturer’s health and safety team, along with specialists from an independent testing facility. It is usually carried out by the equipment supplier, so it is important to ask for the test results when determining containment solutions for dust collectors.

Ask your supplier for current fully surrogate-tested BIBO and liner system results, and do not risk partnering with manufacturers that will not or cannot provide these critical test results.

Explosion Protection for Dust Collectors

Another critical consideration around good system design pertains to the deflagration and explosion risks associated with collecting dust. The level of hazard hinges on the dust’s physical properties, including Kst (rate of pressure rise), Pmax (pressure generated within the collector), and MIE (minimum ignition energy). Manufacturers assess combustibility by conducting explosibility tests following ASTM methods specified by the National Fire Protection Association (NFPA). Unless the dust is inert (Kst = 0), facility operators must integrate explosion protection measures into the dust collection plan.

Given the properties of pharmaceutical dust and its potential for higher Kst values, the risks are elevated, often limiting dust collector location and/or requiring more complex equipment decisions.

Combustible dust explosions pose a threat throughout OSD manufacturing plants, but a critical potential danger zone is within the dust collection system itself. To meet NFPA standards, a range of explosion protection mechanisms and systems are available and are categorized as passive and active systems.

Passive systems are designed to respond to the rising pressure wave by safely directing the growing blast into a safe area, thus reducing risk to personnel and facilities. Active systems, however, are designed to detect the unfolding event in the earliest stages and to actively knock down the risk using a mixture of inert gas and powder prior to its growing out of control.

Passive devices include explosion venting, flameless venting, and isolation valves as flame front barriers. Active systems employ pressure sensors along with chemical isolation, chemical suppression, and fast-acting valves.

Due to the complexities of these options and the risks involved, it is important to find a partner with full understanding and experience in performing a dust hazard analysis (DHA) and identifying options (based on NFPA or the EU’s ATEX requirements). The dust collector provider should also be able to successfully assist you in understanding specific requirements based on your process parameters, collector location, and your authority having jurisdiction (AHJ). Avoid suppliers that downplay the importance of explosion protection, push just a few safety options, or leave it to the process owner to resolve — all of which may leave you at greater risk.

Final Thoughts

We hope this article helps assist you in understanding how critical dust management is in processing OSD pharmaceuticals, particularly with hazardous APIs. Tailored high-efficiency dust collection and filtration systems are key engineering controls that filter harmful substances, mitigate combustible dust risk, and enhance indoor safety. You should collaborate with professional engineering consultants and seasoned equipment suppliers to maximize efficiencies, reduce risks, and improve employee safety when collecting and containing airborne particles.

References

1. Active Pharmaceutical Ingredients Market Size Report, 2030, Grand View Research, https://www.grandviewresearch.com/ industry-analysis/active-pharmaceutical-ingredients-market#.

Author Details

Tony Galvin, Pharmaceutical Segment Manager -Camfil Air Pollution Control

Tony Galvin is the pharmaceutical segment manager with Camfil Air Pollution Control, a manufacturer of dust and fume collection equipment for challenging industrial applications. For more information, call 800-479-6801, or email filterman@camfilapc. com or visit camfilapc.com.

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