Process Analytical Technology


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.

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Note: samples are disposed of 2 weeks after release of test results unless client notified C-Therm of their desire to have the samples returned (client's expense). Any hazardous materials that cannot be disposed of in municipal waste will be returned to client for disposal (client's expense).