Process Analytical Technology

Process Analytical Technology

Process Analytical Technology

Pharmaceutical manufacturers are facing an increased regulatory emphasis on real time evaluation of materials during production. Process Analytical Technology (PAT) – an U.S. FDA initiative – is creating the need for new tools that can provide on-line quality measurements to ensure stringent consistency and performance standards are met.

C-Therm Technologies (formerly Mathis Instruments) in collaboration with major pharmaceutical companies, manufacturers of powder blending equipment, and the FDA, has developed a revolutionary tool to address this need – the ESP™ Pharmaceutical Blend Uniformity Monitoring System.

C-Therm effusivity sensors can differentiate between pharmaceutical ingredients based on their distinct thermal characteristics.

Evaluate, Monitor and Control Blend Uniformity On-line

Using the principles of thermal effusivity, the C-Therm effusivity system employs a network of up to 4 sensors that are retrofitted on blending equipment. At preset intervals throughout the blending process, the sensors – which are mounted flush with the interior walls of the blender – take individual readings from within. Over time, as the blend uniformity increases, the sensor readings begin to converge. When the readings reach the point of lowest relative standard deviation (RSD), the mixture is at its maximum uniformity and blending should stop.

The results are delivered in real time during the blending process, and plotted on the LCD screen of the ESP™ Control Unit.

For a more thorough overview on using effusivity for blend uniformity monitoring, please see the pages under effusivity and Pharma within the Applications section of this website.

Key Advantages of the ESP™

  • Non-destructive process – does not alter excipients or other ingredients
  • Eliminates thieving – does not compromise containment
  • Can be phased in – easy implementation in logical steps
  • Retrofittable – can be incorporated on existing blending equipment
  • Easy to clean and maintain
  • Increased production knowledge – provides valuable information about the blending process, including the detection of deblending
  • Accelerates formulation R&D and scale up, and improves ongoing production – a highly valuable troubleshooting tool
  • Accurate results – strong correlation with HPLC and other methods
  • Cost savings – reduces operating costs and lost revenue due to discarded batches
  • Reduced liability risk
  • Improved batch traceability
  • Offers manufacturers a viable way to address Process Analytical Technology (PAT)

For more information on the C-Therm ESP please contact us for a private consultation regarding your group’s challenges.

  • Designed for a phased integration, the ESP™ networked sensors are engineered for retrofit installation on existing blending equipment.

    Designed for a phased integration, the ESP™ networked sensors are engineered for retrofit installation on existing blending equipment.

  • ESP System

    ESP System

  • Screen information generated by the ESP™ shows test results captured during a test at Patterson-Kelly using a 3 sensor version of the system.

    Screen information generated by the ESP™ shows test results captured during a test at Patterson-Kelly using a 3 sensor version of the system.


When you walk from a hardwood floor onto a ceramic floor in bare feet, the ceramic floor feels colder – even though they are both room temperature. What your feet are detecting is the difference in effusivity between wood and ceramic – in other words, the rate at which these two different materials absorb heat and draw it away from your warm feet. The ceramic has a higher effusivity, and therefore absorbs heat from your feet more quickly, creating the sensation that it is colder.

Every material – whether a solid, liquid, powder or gas – has a specific effusivity value. As illustrated by Table 1 below, that includes the ingredients that comprise pharmaceutical products.

C-Therm has developed and patented highly accurate sensors that detect this unique characteristic of materials. Just like your feet can differentiate between carpet and ceramic, our sensors can differentiate between lactose, Avicel and calcium carbonate, as well as between grades of specific ingredients (see Table 2 below).

 Table 1: Effusivity of Pharmaceutical Ingredients

Blend Ingredient

Average Effusivity

Dies 180
Calcium Carbonate 271
Avicel 367
Flavor 410
Sugar 450
Lactose 490
Air 5

Table 2: Effusivity Range of an Excipient


Mean Effusivity

Standard Deviation

Relative Standard Deviation

Avicel 101 369.21 2.14 0.58
Avicel 102 353.08 1.20 0.34
Avicel 103 333.79 1.71 0.51
Avicel 105 335.67 0.38 0.11
Avicel 112 382.04 2.16 0.56
Avicel 200 355.22 1.70 0.48
Avicel 301 364.73 1.72 0.47
Avicel 302 448.78 1.75 0.39
The effusivity from numerous lots of each grade of Avicel was very precise (<0.6%). Absolute values vary between the grades due to particle size and density.

To find out about specialty chemicals consisting of BioPolymers, visit FMC Corporation.

  • Major ethical pharmaceutical company

    “The effusivity technology has the potential of being an end-to-end product quality monitor; from incoming materials to the blender through to the tablet press.”

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  • FDA Subcommittee on Process Analytical Technology

    “Effusivity has many of the attributes of a valuable PAT tool; on line, non-intrusive, rapid, and related to quality product development.”

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  • “Our area of interest is to correlate effusivity to torque measurement to allow us to determine the endpoint in wet granulation.”

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