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Electrothermal technologies for pharmaceutical granulation: new possibilities for machinery and processes
Integrating microwaves, radiofrequency and induction to improve energy transfer and control of thermal stages in pharmaceutical granulation processes.
Microwave, radiofrequency, and induction are electrothermal technologies that can offer new possibilities for energy transfer and control in pharmaceutical granulation processes, particularly in stages where heat input is essential to the process, such as drying, conditioning, and melting. For companies that develop production lines and machinery, this opens up concrete opportunities to make the granulation process faster, more controllable and more efficient.
A market moving toward more flexible and controllable processes
Pharmaceutical granulation is the process by which particles in a powder mixture are aggregated to form larger granules with physical and dimensional characteristics better suited for subsequent processing steps.
It is one of the most important operations in the production of solid dosage forms, such as tablets and capsules, as it improves flowability, compressibility, and mixture stability, thereby reducing the risk of component segregation.
Today, industrial needs are changing rapidly. The development of increasingly complex molecules and formulations including highly potent active pharmaceutical ingredients (HPAPIs) or temperature-sensitive compounds, requires strictly controlled process conditions and flexible machinery capable of handling different batches, continuous production, and frequent formulation changes.
In this context, electrothermal technologies offer the greatest opportunities in stages where heat plays a necessary role such as drying, conditioning, and melting enabling faster, more selective, and more controllable energy transfer, though they require a case-by-case evaluation.
Main approaches to granulation and the role of thermal energy
Today, pharmaceutical granulation can be categorised into three main process families, each characterised by specific advantages and trade-offs; within wet processes, configurations such as Single-Pot and fluidised bed approaches the drying stage in different ways:
Dry granulation (mechanical compaction)
Suitable for formulations incompatible with water or solvents and for certain heat-sensitive products, it does not require drying; however, compaction can cause localised temperature increases, generate fine dust and make it difficult to achieve uniformity of active ingredients at very low dosages.
Wet granulation
It uses a binding liquid and requires subsequent drying. In single-pot systems, heat transfer through the jacket can result in long processing times and temperature gradients; in a fluidised bed, on the other hand, drying requires large volumes of air, leading to higher energy consumption and difficulties with containment.
Melt granulation
It requires a binder that has been softened or melted through controlled heating and does not require a traditional drying stage. The key process step is temperature control: the energy must be distributed rapidly and evenly, whilst avoiding overheating, incomplete melting and variability in the granules.
Electrothermal technologies for pharmaceutical granulation systems
Granulation must therefore be regarded as an interaction between mechanical, thermal and fluid-dynamic phenomena. In this context, electrothermal technologies are particularly interesting because they allow the necessary energy to be transferred in a more direct, selective and controllable manner, especially during the stages where the thermal contribution has the greatest impact on process performance.
Microwaves, radio frequency and induction represent three possible approaches, based on different mechanisms of energy transfer.
The first two interact with the dielectric properties of the formulation, whilst induction generates heat in conductive metal elements integrated into the machine, which transfer it to the product.
The choice therefore depends on the characteristics of the formulation, the system architecture and the specific process stage.
Microwaves (MW) and Radiofrequencies (RF)
In moist granules, water or a solvent with suitable dielectric properties facilitates the absorption of electromagnetic energy, allowing heat to develop within the mass without relying solely on heat transfer across the machine’s surfaces.
• Microwaves: these are particularly useful in vacuum drying within wet processes. The combination of reduced pressure and volumetric heating can promote rapid evaporation whilst keeping the product temperature relatively low. However, to fully utilise this technology, careful design of the chamber and the field distribution system is required.
• Radiofrequency: as it operates at lower frequencies than microwaves, it can offer different conditions of penetration and energy distribution, making it suitable for larger masses of material, continuous configurations or systems in which dielectric heating is integrated with convective technologies.
However, the actual behaviour depends on the dielectric properties of the entire formulation, the moisture content, the temperature and the distribution of the electromagnetic field.
For this reason, the design must avoid oversimplifications and carefully consider the uniformity of the treatment and any possible local gradients.
Electromagnetic Induction
Electromagnetic induction does not directly heat the product mass, but uses varying magnetic fields to generate heat in specially designed metal components directly within the granulator.
The main advantage lies in the ability to rapidly generate and modulate heat in the desired area, reducing the thermal inertia associated with traditional systems using heat transfer fluids.
In the field of pharmaceutical granulation technologies, this feature can be particularly beneficial when heating forms an integral part of the process, such as in the controlled activation of thermoplastic binders during melt granulation.
A different opportunity for every architectural style
The application of electrothermal technologies varies significantly depending on the machine’s design, the formulation being processed and the required function. Microwaves, radio frequency and induction are therefore not interchangeable solutions: their potential depends on the way in which energy is transferred, the properties of the product and their integration with other functions within the pharmaceutical manufacturing process.
• In single-pot systems, microwaves offer one of the most promising avenues of development. When integrated with a vacuum system and a product handling system, they can directly address the main limitation of this type of equipment: the drying rate. The transfer of energy within the wet mass reduces reliance on heat exchange through the walls, helping to accelerate evaporation whilst keeping the product confined within the same chamber, a particularly important consideration for formulations containing HPAPIs.
To fully capitalise on the process, the design of the electromagnetic system and the control system must ensure adequate field distribution and modulate the power according to the dielectric response of the formulation, which varies during drying as moisture content progressively decreases.
• In twin-screw granulators, microwave and radio-frequency technology can be integrated into dedicated modules installed downstream of the granule formation zone. This configuration would allow drying or conditioning to be incorporated directly into the continuous production line, reducing the need for separate equipment.
A key design consideration is the coordination between applied power, flow rate and residence time: integrated control of these parameters ensures that the treatment remains uniform even as operating conditions vary.
• In fluidised bed systems, dielectric heating can, on the other hand, operate in conjunction with the air flow. Part of the energy required for evaporation is transferred directly to the granules, whilst the air continues to perform the functions of fluidisation and vapour removal.
A hybrid configuration could therefore reduce the thermal load required of the air treatment system, without eliminating its function. Feasibility can be established through an integrated design that takes into account the distribution of the moving product, the uniformity of the field and the interaction with the metal components present in the chamber, so as to identify geometries and operating conditions suitable for uniform treatment.
• A cross-cutting example is melt granulation, in which heating is deliberately used to melt or soften a thermoplastic binder. In this process, microwaves and radio frequency can transfer energy directly to the formulation when its dielectric properties allow it; induction, on the other hand, can be used to heat metal components of the machine rapidly and in a localised manner, such as surfaces, walls or sections of the mixing and extrusion system.
The choice of technology must therefore be based on the most suitable heating mechanism, the thermal compatibility of the active ingredient and the uniformity required during melting and cooling.
From opportunity to industrial solution
In order to integrate electrothermal technology into a pharmaceutical granulation system, it is necessary to start with a specific limitation of the existing process. The first step is to measure its behaviour and define the expected outcome in verifiable terms.
Using representative samples of the formulation, it is then possible to observe how the thermal and dielectric response changes with temperature and moisture content, thereby verifying whether microwaves, radio frequency or induction can offer a real advantage.
Once feasibility has been verified, multiphysics simulation becomes a key tool for design. By integrating thermal and electromagnetic analyses and, where necessary, fluid dynamics and mass transfer, it enables the system’s behaviour to be predicted, any critical areas to be identified and its geometry to be optimised prior to prototyping, thereby reducing time, costs and the number of experimental iterations.
The prototype is then subjected to experimental tests to compare the predictions with the product’s actual response and to collect the data required for the development of the process control system. If the results are consistent and repeatable, the solution can be scaled up to industrial level and integrated with the machine’s other functions.
It is throughout this process that inovaLab supports manufacturers, helping to evolve the numerical model into an experimental system and the prototype into a verifiable industrial solution.
Benefits and prospects for Industry 4.0
The integration of electrothermal technologies can help to redefine certain critical aspects of pharmaceutical processes:
Reduced cycle times
More direct energy transfer can reduce the impact of drying on the overall process time.
Improved containment
Integrating drying into the same equipment or line can reduce product transfers and the associated contamination and containment risks.
Energy efficiency
Energy can be transferred more directly to the target zone or material, reducing the heating of large auxiliary masses such as air, walls and heat transfer fluids.
Adaptive control
Appropriate monitoring instruments to measure parameters such as temperature, residual moisture and torque can be used to modulate the applied power in real time and maintain the process within the desired window.
The industrial value becomes apparent when these advantages are measurable, repeatable and transferable from the laboratory scale to the production scale.
For manufacturers, the opportunity therefore lies in developing hybrid and modular platforms in which microwaves, radio frequency and induction are integrated exclusively in those stages where the process requires drying, heating or controlled thermal activation, combining performance, energy efficiency and product quality.
Do you have a project in mind? Get in touch with our team.
We support companies developing innovative technologies throughout all the critical stages of the innovation process: from analysing and understanding the problem through to formulating and implementing technically sound and verifiable solutions.
Do you have a project in mind? Get in touch with our team.
We support companies developing innovative technologies throughout all the critical stages of the innovation process: from analysing and understanding the problem through to formulating and implementing technically sound and verifiable solutions.
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