Application PNR 12: Consistency of Carboxymethylcellulose Sodium Paste

The penetrometer PNR 12 allows a rating of the plasticity or consistency of carboxymethylcellulose sodium paste containing products.

PNR 12 – Test Principle

The PNR 12 is a gravity penetrometer and measures the resistance a material provides against being pierced by a specifically shaped test body.
The penetration, which is indicated in penetration units of 0.1 mm per unit, allows a rating of the plasticity or consistency.

The measurement of consistency by penetration is described by the European Pharmacopeia, the U.S. Pharmacopeial Convention and other national or international standards like ASTM, EN, ISO etc.

Sodium Carboxymethylcellulose (CMC or SCMC)

CMC is a cellulose derivative, an ionic cellulose gum. It is widely used in various industrial fields owing to its unique thickening, suspending, adhesion, and water retention properties. CMC supports film-forming, stabilization, fluid loss control, thickening and suspending effects for various products. For example: ointments, medical gel or plaster, toothpaste, gluten-free bread, yogurt, ice cream, protein food, emulsions.


This application flash gives an example on how to measure carboxymethylcellulose sodium paste in the pharmaceutical industry.

PNR 12 Penetrometer
Using the penetrometer PNR 12 together with the Test Kit “Optional Hollow Cone - Petrolatum”, the consistency measurement of carboxymethylcellulose sodium paste will be according to the U.S. Pharmacopeia.


Fig. 1: PNR 12 basic unit


Test Kit “Optional Hollow Cone – Petrolatum” (106933)
consisting of:
1 optional hollow cone, 102.5 g
1 plunger, 47.5 g
1 sample container


Fig. 2: Test kit “Optional Hollow Cone – Petrolatum”

Consistency Measurements of
Carboxymethylcellulose Sodium Paste
Sample 1 2
1. Test result [0.1 mm] 333 315
2. Test result [0.1 mm] 327 319
3. Test result [0.1 mm] 328 317
Mean value [0.1 mm] 329 317

Do you have any questions?

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Learn more about the PNR 12

Good to know

U.S. Pharmacopeia (USP) -The U.S. Pharmacopeial Convention describes in USP procedures not only how to measure the identity, quality and purity of medicinal or food ingredients but the consistency measurement by penetration method for carboxymethylcellulose sodium paste, too. 
According to the USP, the paste contains between 16.0 % and 17.0 % sodium carboxymethylcellulose.