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Why Wurster systems strain under high-dose substrate loading

Within a Wurster process, pellets cycle vertically through a spray column where solution is layered incrementally. Fluidising air circulates particles between the spray region and the drying zone.

As layer thickness increases, solvent evaporation becomes the primary constraint. Raising concentration to reduce solvent increases viscosity and nozzle blockage risk, while lowering concentration raises overages and extends drying time.

PEPT and CFD-DEM studies demonstrate that particles spend only 12–29% of each cycle inside the Wurster tube. The remaining time involves circulation and heat/mass transfer outside the spray zone, slowing the overall spray-dry rhythm relative to rotor systems.

Tangential rotor spraying integrates wetting and drying

Modern Wurster-capable fluid beds often allow rotor integration for tangential spraying. Rotor operation fundamentally reshapes particle motion. With airflow, centrifugal force, and gravity acting together, particles follow a spiral path around the chamber.

Shear forces and particle collisions distribute droplets effectively, increasing exposed surface and limiting local solvent pooling.

Unlike intermittent Wurster exposure, all pellets remain in continuous motion. Therefore, layering, mixing, and drying proceed in parallel.

Synchronised rotary variables are essential

Spray rate, atomisation pressure, and rotor speed govern PSD and growth patterns. High spray rates combined with low atomisation pressure yield larger droplets that evaporate slowly, forming larger agglomerates and broadening PSD5. Higher pressures generate finer droplets that narrow PSD.

Rotor speed adds a moisture-dependent mechanical influence. At low spray rates, high speeds break apart dry agglomerates. At high spray rates, high speeds densify wet, deformable pellets, enlarging them5.

Rotor systems tolerate elevated deposition, but independently increasing either parameter can destabilise the process.

Dry powder layering shifts liquid to adhesive function

Even in tangential spraying, evaporation governs process limits. Dry powder layering changes the liquid’s role from carrier to binder.

By co-spraying binder and API powder, liquid per pellet is minimised and drying time shortened.

Relative to solution spraying, powder layering can reduce solvent consumption by up to 80% and decrease process duration by nearly 50%.

60% shorter processing for a global CDMO

A regulated-market CDMO recently developed a Wurster process for Lansoprazole Capsules.

Spray concentration was limited to 25% to avoid clogging. Lower concentration required more solvent for the same drug loading, while overages were capped at 5%. Increasing solution volume was not acceptable.

Partnering with ACG Laboratories, they transitioned to rotor-based dry powder layering.

A rotor and powder feeder were added to the existing unit, enabling rapid mass increase with minimal changes and modest investment.

Results included:

60% reduction in process time (12 to nearly 5 hours) 70% reduction in solvent usage Removal of 5% material overage 100% pellet coating efficiency

Conclusion

Wurster systems deliver uniform coatings effectively. Yet high-dose layering is constrained by evaporation and intermittent exposure.

Rotor-based tangential spraying enables simultaneous wetting, mixing, and drying. Dry powder layering further lowers solvent requirements by redefining liquid as adhesive.

As pharmaceutical therapies become more complex and patient-focused, packaging has emerged as a critical factor in ensuring product stability, safety, and sustainability.

ACG, a 65-year-old global company headquartered in India, has built its leadership position by offering integrated solutions across capsules, barrier packaging, engineering systems, and inspection technologies.

“We are Asia’s largest capsule manufacturer and the second-largest globally,” says Dr Sheikh Akbar Ali, general manager and head of development and technology at ACG. “Our patented capsule-in-capsule technology enables the combined delivery of solids and liquids, giving us a distinct technological advantage.”

This innovation is particularly relevant in nutraceuticals, where combinations such as oils and powders increasingly need to be delivered in a single dosage format.

From capsule science to barrier performance

ACG’s operations are defined by integration. Beyond manufacturing hard gelatin and plant-based capsules, the company provides laboratory services, regulatory support, machine compatibility testing, and customised solutions.

Vegetarian capsules produced by ACG are now entirely plant-based. “Our Aurangabad facility focuses exclusively on plant-based capsules,” Dr Ali explains. “Gelatin capsules are sensitive to heat and moisture, which can cause sticking or degradation, whereas plant-based capsules offer greater stability.”

Packaging materials are manufactured in-house and include high- and ultra-high-barrier films and foils designed to protect drugs from moisture, oxygen, and light. Moisture can lead to hydrolytic degradation, while oxygen exposure can cause oxidation.

“We test barrier properties under varying temperature and humidity conditions and also assess performance after blister formation to simulate real-use environments,” says Dr Ali.

ACG supplies both thermoform and cold-form blister packs. Thermoform blisters use heated PVC films, while cold-form blisters rely on aluminium laminates shaped at room temperature. “Cold-form blisters offer superior protection for highly sensitive medicines, but they are bulkier,” Dr Ali notes.

Although cold-form packs are difficult to recycle, aluminium can be recovered through pyrolysis without toxic emissions. Recycling thermoform blisters remains challenging due to multi-material structures.

Portfolio strength and global presence

ACG’s capsule portfolio includes gelatin and HPMC hard-shell capsules suitable for powders, pellets, liquids, tablets, and mini-capsules. Over 10,000 colour shades, pearlescent finishes, and anti-counterfeiting print options support brand differentiation. Clean-label vegetarian capsules using natural pigments and titanium dioxide-free opacifiers are also available, along with R&D services such as compatibility testing and stability studies.

Packaging laminates, specialised foils, and integrated machinery solutions are supported by an engineering division supplying equipment for granulation, capsule filling, tablet compression and coating, blistering, cartoning, and track-and-trace systems.

With operations in nearly 140 countries, ACG continues to expand its manufacturing footprint, including a recently opened packaging facility in Croatia and planned expansion across Europe.

Responding to market pressures

Pharmaceutical packaging growth is driven by ageing populations, chronic disease prevalence, and increasing product complexity. Logistics remain a challenge, particularly for gelatin capsules transported through hot climates.

“During sea transport, container temperatures can exceed 40°C, causing capsules to soften or stick,” Dr Ali says. Material transitions away from PVC will be gradual, he adds, as alternatives must meet strict regulatory and performance requirements.

DryPod™ offers a unique advantage with its patent-clean engineering

ACG, recognised globally as a fully integrated provider of solid-dosage and packaging systems, has launched DryPod™, an advanced cold-form laminate incorporating desiccant technology to protect moisture-sensitive drug molecules.

DryPod™ signals a major upgrade for pharmaceutical manufacturers who have faced persistent challenges related to supply restrictions, inflexible co-extrusion solutions, and ongoing compatibility issues with existing desiccant cold-form structures.

Moisture protection plays a vital role in preserving drug effectiveness throughout retail distribution. Current market solutions, however, rely overwhelmingly on one dominant patented co-extrusion process, creating operational bottlenecks such as equipment limitations, dependence on designated lidding foils, extended sourcing cycles, minimal supplier diversity, and varying levels of technical support.

DryPod™ breaks through these constraints, enabling companies to maintain product integrity without sacrificing operational agility or regulatory robustness.

In contrast to traditional co-extruded formats, DryPod™ is produced using a proprietary lamination technology that ensures consistent performance across all standard blister-forming systems. This removes the requirement for specialised retrofits, allowing manufacturers to deploy DryPod™ seamlessly on existing production infrastructure. Its compatibility with any PE-sealable lidding foil further streamlines procurement and boosts supply-chain responsiveness.

The Wurster coating technique is indispensable in multiparticulate formulation development, particularly for controlled-release pellets, taste-masked systems, and targeted delivery technologies. Yet, scaling this process is never a matter of simply multiplying settings. The real challenge lies in maintaining the intricate balance among spray formation, moisture evaporation, and particle circulation. Disturb any one of these elements, and the system becomes prone to agglomeration, premature drying, erratic film growth, or inefficient coating yield. This discussion outlines how to preserve these essential dynamics during scale-up.

Spraying Principles

The spray subsystem defines the conditions in which droplets are generated and delivered to particle surfaces. Misalignment of spray parameters can disrupt the process in several ways.

Over-wetting typically stems from droplets that are too large for the available drying capacity. This often arises from high-viscosity coating dispersions, concentrated solid content, insufficient atomisation air, or spray rates that exceed the system’s ability to evaporate solvent in a timely manner.

Spray drying occurs under opposite conditions when droplets evaporate mid-flight. High atomisation pressures, low-viscosity formulations, or excessive nozzle-to-bed distances produce fine droplets with large surface-area-to-volume ratios. These droplets remain suspended in warm air for extended periods, accelerating evaporative losses and resulting in powdery deposits rather than cohesive films.

Uniformity of coating is shaped by the geometry of the spray pattern. Narrow angles deliver deeper penetration into the Wurster column but risk concentrating wetting within a narrow region. Conversely, wide spray angles provide broader coverage but depend heavily on proper nozzle height to prevent losses from overspray or inadequate surface wetting.

Spraying only establishes the starting conditions for coating. True success depends on the alignment of droplet formation with simultaneous drying and circulating forces.

Drying Dynamics

Drying is the mechanism that converts a wet deposit into a continuous film. However, achieving ideal film formation requires the right balance between temperature, humidity, and airflow.

Over-wetting develops when drying is sluggish. Low inlet air temperature, high humidity (high dew point), or insufficient airflow all slow down solvent removal. Sticky surfaces persist longer, increasing the risk of particle bridging and mass agglomeration.

Premature drying occurs when droplets lose solvent earlier than intended. High inlet or product temperatures, overly high air volume, or extremely dry air conditions (low dew point) harden droplets in mid-air, preventing them from spreading on the particle surface. This produces poor adhesion and weak, fragmented films.

Inconsistent coating emerges from poor temperature control relative to the coating polymer’s requirements. Aqueous coatings are especially sensitive to falling below the polymer’s minimum film-forming temperature, which can create brittle layers. Extremely dry air also elevates electrostatic charge, particularly with non-polar coating systems, increasing bed-wide agglomeration.

Drying control is therefore about orchestrating solvent removal at the precise moment droplets land, ensuring coalescence rather than premature solidification.

Fluidisation and Circulation Control

Particle motion underpins the entire Wurster process. Stable fluidisation ensures repeated movement through the spray and drying zones, creating the cyclical exposure required for uniform coating.

Agglomeration often results from excessive fill levels. A dense bed limits mobility and increases the frequency of collisions between wet particles. If inlet air velocity is insufficient—often due to constricted annular gaps—fluidisation weakens, further increasing the probability of agglomerate formation.

Premature drying related to circulation can occur under high airflow conditions. Excessive velocity accelerates droplet evaporation, leading to dried particles before they reach the pellet surface.

Irregular coating distribution is the most common circulation-related issue. A broad particle size or density distribution generates uneven residence and cycle times. Larger particles may remain longer in the spray region while visiting it less frequently, accumulating more coating per exposure and shielding smaller particles. Underfilled beds introduce unnecessary turbulence, and incorrectly set partition heights disrupt the pressure gradient needed for consistent particle draw-in. Tall partitions reduce draw-in efficiency, while short ones restrict exposure time.

Monitoring the pressure drop across the distributor plate provides a practical diagnostic tool. A sudden drop indicates partial collapse of the fluidised bed, whereas slow declines typically indicate entrainment losses. Stable circulation demands proper airflow scaling, consistent particle size distribution, and careful control of draw-in forces.

Variables to Standardise Early in Development

Certain parameters should be set firmly during development, as modifying them during scale-up complicates the process significantly.

Distribution-plate selection must align with column size and particle characteristics to maintain fluidisation consistency at all scales.

Atomisation pressure, despite interacting with spray rate and nozzle design, should be optimised during early trials. This pressure dictates droplet size, spray penetration, and deposition behaviour.

Environmental factors such as dew point, inlet air temperature, and product temperature should remain constant. They directly influence drying rate, polymer film formation, and coating robustness. Significant changes during scale-up should be avoided unless supported by process data.

These elements function as structural anchors for the coating process. Once established, they should remain unchanged while scaling focuses on variables responsive to equipment capacity.

Strategies for Scaling Up

Scaling requires equipment similar in geometry across development, pilot, and commercial units. When this structural consistency exists, mathematical scaling becomes both logical and effective.

Volumetric airflow should increase in direct proportion to the column’s cross-sectional area to maintain linear fluidisation velocity. Spray rate must scale equally with column area to sustain the intended exposure-to-drying ratio. Partition height should adhere to recommended ranges for each column size and will naturally increase as particle diameter grows during coating.

Variables that should be protected across all scales include:

Spray rate, scaled with airflow and column area

Atomisation pressure, adjusted only to maintain equivalent droplet properties

Air volume, scaled to preserve circulation and drying capacity

Inlet air temperature, held constant to stabilise product temperature

Dew point, maintained to control solvent evaporation and static charge

Fill level, matched as a percentage of equipment capacity

Partition height, maintained to preserve the required pressure gradient

Even with correct mathematical relationships, increased batch mass alters total heat load and moisture retention. Early pilot-scale batches typically require iterative adjustments to restore equilibrium.

Particle-Level Insights from Research

While increasing atomisation pressure is commonly used to maintain droplet size at higher spray rates, this approach carries risks. Higher droplet momentum increases the likelihood of pellet attrition and the generation of fines—particularly in regions near the nozzle where larger particles tend to linger.

Computational and tracer-based studies consistently show that residence-time distribution determines coating uniformity. Larger pellets spend longer within the spray zone during each pass but cycle less frequently, accumulating more coating and shading smaller particles. Recirculation events where particles re-enter the spray zone opposite airflow expand this variability further.

Simulations validated by positron emission particle tracking highlight that inlet airflow rate and column height strongly influence particle movement patterns. Errors in scaling these two variables magnify coating variability dramatically at larger scales.

Additional research reveals that solvent evaporation is extremely sensitive to inlet air temperature, while airflow strongly governs coating yield and material losses. CFD–DEM models demonstrate that coordinated optimisation of airflow, spray rate, and drying temperature can significantly reduce spray-drying losses and shorten processing time.

Conclusion

Across the pharmaceutical industry, companies are taking meaningful steps to curb their environmental impact—switching to renewable energy, modernizing plants, and optimizing logistics. Yet, despite these visible efforts, the majority of emissions remain hidden beyond the factory gate, embedded in complex networks of suppliers and partners. Regulators and investors are now extending their scrutiny into these areas, demanding full visibility across the value chain. This shift is quietly transforming the industry’s definition of competitiveness and risk. A challenge once viewed as secondary is now emerging as one of pharma’s most critical strategic priorities—and time for decisive action is running short.

Capital Now Follows Carbon Transparency

Financial markets are reshaping faster than ever, and sustainability is the new standard of credibility. Institutional investors have become increasingly intolerant of poor ESG performance. A 2022 PwC survey revealed that nearly 90% of investors had already divested or planned to divest from companies lacking solid ESG strategies, with 78% identifying regulatory exposure as their top concern.

This change is particularly relevant to the pharmaceutical sector, where access to long-term capital underpins innovation, R&D, and infrastructure expansion. Investors are now rewarding transparency—favoring companies that can account for and control their emissions, including those arising from suppliers and distribution networks.

Adding to the momentum, ESG funds have been outperforming broader market indices, making sustainability synonymous with stability. The logic is simple: companies that understand their carbon exposure are better equipped to manage broader business risks.

Governments are responding with formal mandates. The EU Corporate Sustainability Reporting Directive (CSRD), effective mid-2026, requires companies to publicly disclose their greenhouse gas emissions across:

Scope 1: Direct emissions from owned facilities

Scope 2: Indirect emissions from purchased energy

Scope 3: All upstream and downstream emissions—typically 75% of a pharma company’s total footprint

In the U.S., the Securities and Exchange Commission (SEC) has introduced similar disclosure requirements for Scope 1 and 2 emissions. While Scope 3 remains voluntary, investors increasingly demand this data to assess long-term financial health. For pharma, the ability to demonstrate comprehensive emissions transparency is fast becoming a precondition for capital access.

When Carbon Becomes a Cost Driver

Europe’s Emissions Trading System (ETS) has fundamentally linked carbon emissions to economics. It caps emissions from major industrial sectors and forces companies to buy carbon allowances. Since 2021, the annual cap has tightened by 2.2%, consistently raising carbon prices. Although the pharmaceutical industry itself is not a direct participant, its material suppliers—especially in packaging, chemicals, and energy—are. These upstream costs cascade through the supply chain, shaping the overall carbon and cost structure of pharmaceutical production.

The Carbon Border Adjustment Mechanism (CBAM), launched in 2023, adds another dimension. Designed to prevent “carbon leakage,” CBAM requires importers to declare the carbon intensity of covered materials. From 2026 onward, importers will also need to pay a carbon price equivalent to the EU ETS rate.

The consequence is clear: carbon emissions now carry a tangible financial cost. For pharma manufacturers, inaction on emissions reduction—especially within supply chains—means rising exposure to both price volatility and regulatory pressure.

Packaging: The Overlooked Sustainability Accelerator

Pharmaceutical packaging contributes up to 15% of total industry emissions, according to McKinsey’s 2023 analysis. Encouragingly, that same report estimates potential reductions of up to 90% by 2040 through optimized packaging design and the use of low-carbon materials. This makes packaging one of pharma’s most immediate and high-impact sustainability opportunities.

The industry’s continued dependence on aluminum and fossil-based plastics is rooted in functionality—they deliver the sterility, machinability, and barrier protection required for drug safety. However, these materials are also among the most carbon-intensive. Producing a single tonne of fossil-based plastic emits roughly five tonnes of CO₂, while virgin aluminum can release over 14 tonnes per tonne produced. With carbon pricing mechanisms tightening, these traditional materials are becoming both environmental and financial liabilities.

Experts from EY and KPMG predict that CBAM’s coverage will soon expand to plastics and downstream packaging, meaning pharmaceutical companies will need to account for the carbon intensity of their materials. Packaging is no longer just a means of protection—it’s a determinant of cost efficiency, brand reputation, and investor confidence.

Regulatory Exemptions: Temporary by Design

While pharmaceutical packaging currently benefits from limited exemptions under global recyclability and circular economy policies, these are transitional measures rather than permanent shields.

California’s SB 54 mandates a 25% reduction in single-use plastic packaging by 2032, with 65% of all materials recycled and 100% recyclable or compostable. Drug packaging and medical devices are temporarily exempt.

The EU Packaging and Packaging Waste Regulation (PPWR) sets the goal of full recyclability by 2030, with medicinal packaging exempt only until 2035.

In the UK, under the Extended Producer Responsibility (EPR) scheme, pharma packaging faces reduced fees but not total exemption due to sterility requirements.

These carve-outs are effectively grace periods. As new materials emerge that meet pharmaceutical safety and performance standards, the justification for exemptions will erode. Companies that invest early in recyclable, compostable, and low-emission packaging will transition smoothly when these protections expire.

Rethinking Materials for Function and Footprint

Pharma’s next frontier lies in balancing environmental responsibility with performance integrity. Material innovation is now centered on reducing emissions while maintaining protection, shelf life, and compliance.

Mono-material packaging made of polypropylene (PP) or polyethylene terephthalate (PET) eliminates recyclability challenges found in PVC-aluminum composites.

Bio-based plastics such as bio-PET and bio-PE, derived from renewable sources like sugarcane, lower carbon emissions while retaining recyclability.

Polylactic acid (PLA), a biodegradable polymer, is ideal for select applications with less stringent barrier needs.

Cyclic olefin polymers (COPs), used in advanced pre-filled syringes, combine lightweight design with lower emissions during manufacturing and sterilization.

At ACG, innovation is translating into real progress. We are advancing the development of recyclable, compostable, and biodegradable primary packaging while decarbonizing our operations and collaborating with supply partners to reduce Scope 3 emissions. Each step contributes to creating a more sustainable pharmaceutical ecosystem.

Conclusion: Turning Packaging into Competitive Advantage

Pharmaceutical packaging has moved from being a functional necessity to a strategic enabler. It now influences cost management, regulatory readiness, and access to green finance. Scope 3 emissions and packaging waste are no longer peripheral—they are becoming central financial considerations.

As global sustainability frameworks shift toward full lifecycle accountability, the pressure to cut emissions and enhance recyclability will only intensify. Companies that act now—by redesigning packaging systems and rethinking material sourcing—can transform compliance into differentiation. Those that delay risk facing regulatory shocks and lost investor confidence.

Not long ago, a supplement needed only to demonstrate effectiveness. But today, efficacy is just the starting point. Modern consumers expect products to be clean, transparent, and respectful of cultural and dietary values. From veganism to religious certifications, these expectations are rapidly becoming non-negotiable.

The meaning of clean label in supplements

“Clean label” emerged in food and beverage, reflecting consumer concern about artificial ingredients. It now drives supplement expectations. Though loosely defined, it generally means:

Short ingredient lists with natural, easy-to-recognize components.

Free from synthetic additives, colors, and chemical preservatives.

Contaminant-free, including absence of heavy metals, pesticides, or antibiotics.

Demand is strongest in Europe and North America, where consumers actively seek natural or non-GMO claims. Studies show that 75% of Americans use supplements regularly, while more than half of Europeans prefer “natural” and 84% carefully read labels before buying.

Beyond safety, consumers also expect cultural inclusivity—labels now routinely state “halal,” “kosher,” “vegan,” and “plant-based.”

Instead of regulators, it is retailers who are embedding these standards into product access.

Retail policies setting the tone

Whole Foods Market has banned more than 150 ingredients from its supplement shelves, focusing not only on safety but also necessity and availability of better alternatives.

In the UK, Holland & Barrett restricts preservatives, plasticizers, binders, and certain synthetic sweeteners, limiting shelf access for many traditional formulations.

Online platforms mirror these efforts. iHerb emphasizes transparency through consumer filters (vegan, halal, preservative-free), while Vitacost uses ingredient tags and certifications to highlight clean options.

Clean standards enter the mainstream

In 2022, Target introduced its Clean program, extending clean-label principles to supplements and OTC medicines. Amazon likewise enables filtering for non-GMO, vegan, and allergen-free supplements.

This mainstream adoption signals that clean label has moved beyond niche wellness markets into general retail.

Retail and digital pressure combined

Algorithms, shelf placement, and filter systems increasingly determine whether products are visible. For brands, failing to meet clean label expectations means exclusion or low ranking, requiring greater investment in direct marketing to maintain presence.

Reformulation challenges by dosage form

Brands aiming to align with clean label must rethink formulations. Each dosage form carries unique hurdles:

Gummies: Attractive but prone to stability issues. Natural sweeteners and fruit bases affect taste and moisture, while lack of preservatives shortens shelf life.

Softgels: Effective for oils but dependent on gelatin, limiting vegan or halal claims. Plant-based alternatives increase costs and manufacturing complexity.

Tablets: Economical but excipient-heavy. Natural substitutes reduce compressibility, increase microbial risks, and create variability.

These difficulties highlight the need for more compatible formats.

Hard capsules: the clean solution

Hard capsules require minimal excipients and are inherently suited to clean label positioning.

ACGcaps™ H+, certified by the Clean Label Project, sets a new standard. Its shell is made only from cellulose and water, making it both simple and inclusive across dietary needs. It also supports diverse formulations, from powders to oils.

ACG innovations—such as NTone natural colors, TSafe TiO₂-free opacifiers, and vegan printing inks—reinforce clean label authenticity and allow brand differentiation.

Advantages of ACGcaps™ H+:

Minimalist and stable composition.

Plant-based, suitable for vegan, kosher, and halal needs.

Natural taste- and odor-masking without extra agents.

Ready-to-fill, simplifying production timelines.

Conclusion

Retailers and digital platforms are now the arbiters of supplement standards, enforcing clean label expectations more strongly than regulators.

In tablet and capsule production, high-shear mixer (HSM) granulation remains the most widely used wet granulation technique. Although it consistently produces well-formed granules, identifying the exact endpoint of the process poses ongoing challenges. Manufacturers rely on various detection methods, each with its own advantages and limitations. This article reviews these methods and spotlights a leading approach.

Why the Endpoint Matters

More than 70% of global granulation processes use wet granulation, with HSM preferred for its control and efficiency. Determining the endpoint accurately is vital to achieving target granule attributes like strength, density, particle size uniformity, and flowability — all of which influence final tablet performance.

Even with technological progress, empirical observation remains common, leading to variable outcomes. Manual inspections are still prevalent but can lack consistency. Any reliable method must also consider factors such as mixer dimensions, rotational speed, production scale, and binder application technique.

HSM granulation involves three stages: dry mixing, binder application, and wet mixing. While wet mixing plays the dominant role in shaping the endpoint, binder addition significantly influences particle nucleation and densification. Accurate determination must account for both.

Monitoring impeller load via motor current is a widely used practice, but with HSM’s broad particle size distribution, precision in this step is critical.

Common Endpoint Detection Methods

Wet mixing time: Based on duration after binder addition; prone to variation from raw materials and operator handling.

Motor current monitoring: Tracks resistance during mixing; influenced by multiple factors.

Calculated torque: Derived from motor current; susceptible to AC motor inconsistencies.

Reaction torque sensing: Measures force on stationary motor base; accuracy affected by mixing fluctuations.

Torque rheometry: Offline method for granule rheology; no real-time capability.

Acoustic monitoring: Detects particle property shifts; effective but expensive.

NIR spectroscopy: Assesses moisture content; not always precise for endpoint.

Focused beam reflectance measurement: Measures particle size changes; accurate but costly.

Direct torque measurement: Provides real-time torque readings directly from the impeller shaft, minimizing error.

Key Components for Direct Torque Measurement

Integrated torque sensor on impeller shaft

Contactless transmission

Pre-calibrated device

HMI with live readings

Programmable endpoint thresholds

Takeaway

As the pharmaceutical industry moves towards increasingly complex drug formulations, the role of tablet coating technology has evolved from a cosmetic necessity to a functional imperative. Today’s tablet coaters must meet a wide array of performance, regulatory, and operational standards—all while enabling precision and flexibility.

Initially, pan coating techniques were limited in efficiency, leading to inconsistent coatings and prolonged batch times. Even the improved Pellegrini pan couldn’t overcome fundamental process limitations. The true advancement came with perforated coating pans, which dramatically improved drying and coating precision, making them a cornerstone of modern pharmaceutical coating.

Pharmaceutical companies now demand machines that can coat tablets for a variety of purposes—moisture protection, taste masking, controlled release—while ensuring speed and repeatability. Machines like the SMARTCOATER X•ONE offer exactly this: robust performance, flexibility across batch sizes, and intelligent design that supports ergonomic and cleaning ease.

One key enhancement lies in airflow management. By isolating the drying zone from the spraying zone, coaters prevent turbulence and ensure optimal film formation. Tablets dry evenly before being reintroduced to the spray, reducing coating defects.

Drum and baffle geometry have been refined to guarantee consistent mixing and gentle tablet handling. Enhanced radial and axial mixing helps prevent uneven coating, especially with smaller loads or delicate tablets.

Spray technology has also matured. SMARTCOATER X•ONE’s patented nozzles offer optimal atomization, reduced clogging, and ease of cleaning. Quick-release designs improve operator safety and productivity.

Large batch production is facilitated by expanding drum length rather than diameter—preserving spray efficiency and avoiding deep beds that damage tablets. Batch size versatility, from 10% to full capacity, makes coaters adaptable for R&D through to commercial production.

In terms of sanitation, integrated WIP systems with optimized water collection and detergent compatibility support fast, effective cleaning. Features such as sloped surfaces and directional wash jets eliminate contamination risks.