Uniaxial Powder Testing for Optimizing High Shear Wet Granulation

In order to assess and rank powder flowability for a large scope of powder handling processes in various industries, including construction, pharmaceutical, chemical and  food, uniaxial Unconfined Yield Strength (uUYS) can be employed.

This article outlines a study which uses the Uniaxial Powder Tester (UPT) to characterize a range of pharmaceutical blends and the corresponding granulates to show how uUYS values can clearly differentiate between the formulations and quantify the effect of the granulation process conditions.

Uniaxial Powder Testing for Optimizing High Shear Wet Granulation

The first step in uniaxial testing involves the construction of a powder column at a given Major Principal Stress (MPS or σ1), next the confining sleeve is removed and the freestanding column of material is fractured.

The force which is needed to break the column shows on the uUYS (σC) of the powder. The UPT also permits bulk powder properties such as compressibility and density to be established.

Consolidation studies may also be performed in a number of environments by utilizing an off-instrument Consolidation Station. Samples may be consolidated at a specific humidity and/or temperature for extended periods of time.

Uniaxial Powder Testing for Optimizing High Shear Wet Granulation

Experimental Set-Up

 

Mixtures which contain different ratios of microcrystalline cellulose (MCC) and lactose were dry mixed for 3 minutes in a turbula mixture (total powder volume 750 ml). The resulting dry mixtures were then put through a wet granulation process, where the volume of water necessary was added over 90 seconds.

The powder was pre-consolidated at 8 kPa for 5 seconds during uniaxial testing. Using a unique double-ended compaction technique, an MPS of 40 kPa was then applied for 30 seconds before the uUYS was measured, alongside the compressibility, Poured Bulk Density (BDP), and Consolidated Bulk Density (BDC).

The first part of this experiment assessed a 50:50 mixture of lactose and MCC with varying levels of water content utilized throughout granulation. The second phase looked at differing ratios of lactose: MCC with fixed 40 % water content.

For a further 180 seconds the granulation process was continued and the resulting wet mass was then screened through an 850 µm sieve, dried at 60 °C for 7 hours and then re-screened through a 2 mm sieve.

Dry Mix % Water
% Lactose % MCC
15 85 0, 40
30 70 0, 40
50 50 0, 10, 20, 30, 40
70 30 0, 40
85 15 0, 40

 

The powder was pre-consolidated at 8 kPa for 5 seconds during uniaxial testing. Using a unique double-ended compaction technique, an MPS of 40 kPa was then applied for 30 seconds before the uUYS was measured, alongside the compressibility, Poured Bulk Density (BDP), and Consolidated Bulk Density (BDC).

The first part of this experiment assessed a 50:50 mixture of lactose and MCC with varying levels of water content utilized throughout granulation. The second phase looked at differing ratios of lactose: MCC with fixed 40 % water content.

    Results - Water Content

The following findings relating the flow properties of the dry mix and granules were demonstrated:

Want to know more? Click here to read the full article.

This information has been sourced, reviewed and adapted from materials provided by Freeman Technology.

For more information on this source, please visit Freeman Technology.

Citations

Please use one of the following formats to cite this article in your essay, paper or report:

  • APA

    Freeman Technology. (2020, May 07). Uniaxial Powder Testing for Optimizing High Shear Wet Granulation. AZoM. Retrieved on September 22, 2020 from https://www.azom.com/article.aspx?ArticleID=18736.

  • MLA

    Freeman Technology. "Uniaxial Powder Testing for Optimizing High Shear Wet Granulation". AZoM. 22 September 2020. <https://www.azom.com/article.aspx?ArticleID=18736>.

  • Chicago

    Freeman Technology. "Uniaxial Powder Testing for Optimizing High Shear Wet Granulation". AZoM. https://www.azom.com/article.aspx?ArticleID=18736. (accessed September 22, 2020).

  • Harvard

    Freeman Technology. 2020. Uniaxial Powder Testing for Optimizing High Shear Wet Granulation. AZoM, viewed 22 September 2020, https://www.azom.com/article.aspx?ArticleID=18736.

Ask A Question

Do you have a question you'd like to ask regarding this article?

Leave your feedback
Submit