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Have you had challenges with CM adhesion/cohesion? Experts are discussing this topic in the Oral Solid Dosage Group,, broken out into the following key areas: conveying, feeding, transfer hoppers, and transition pipes. Learn from their experience by reading the full conversation here:

A modified Kushner-Moore approach to characterising small-scale blender performance impact on tablet compaction

By Hikaru G. Jolliffe1; Martin Prostredny1; Carlota Mendez Torrecillas1; Ecaterina Bordos1; Collette Tierney1; Ebenezer Ojo1; Richard Elkes2; Gavin Reynolds3; Yunfei Li Song2; Bernhard Meir4; Sara Fathollahi5; John Robertson1

1. CMAC, Technology and Innovation Centre 2. GSK Ware R&D 3. Oral Product Development, PT&D, Operations, AstraZeneca UK Limited 4. Gericke AG 5. DFE Pharma

Published on CMKC


Continuous Direct Compaction (CDC) has emerged as a promising route towards producing solid dosage forms while reducing material, development time and energy consumption. Understanding the response of powder processing unit operations, especially blenders, is crucial. There is a substantial body of work around how lubrication via batch blender operation affects tablet critical quality attributes such as hardness and tensile strength. But, aside from being batch operations, the design of these blenders is such that they operate with low-shear, low-intensity mixing at Froude number values significantly below 0.4 (Froude number Fr being the dimensionless ratio of inertial to gravitational forces). The present work explores the performance of a mini-blender which has a fundamentally different mode of operation (static vessel with rotating blades around a mixing shaft as opposed to rotating vessel with no mixing shaft). This difference allows a substantially wider operating range in terms of speed and shear (and Fr values). The present work evaluates how its performance compares to other blenders studied in the literature. Tablet compaction data from blends produced at various intensities and regimes of mixing in the mini-blender follow a common trajectory. Model equations from literature are suitably modified by inclusion of the Froude number Fr, but only for situations where the Froude number was sufficiently high (1 < Fr). The results suggest that although a similar lubrication extent plateau is eventually reached it is the intensity of mixing (i.e. captured using the Froude number as a surrogate) which is important for the lubrication dynamics in the mini-blender, next to the number of revolutions. The degree of fill or headspace, on the other hand, is only crucial to the performance of common batch blenders. Testing using alternative formulations shows the same common trend across mixing intensities, suggesting the validity of the approach to capture lubrication dynamics for this system.


International Journal of Pharmaceutics



Type of publication

Peer-reviewed journal


  • CMAC, Technology and Innovation Centre
  • GSK Ware R&D
  • Oral Product Development, PT&D, Operations, AstraZeneca UK Limited
  • Gericke AG
  • DFE Pharma GmbH & Co.

Article Classification

Research article

Classification Areas

  • Oral Solid Dosage