Knowledge Base

Shaped Catalyst Body Preparation with MTR and Caleva Screw Extruder

 Shaped Catalyst Body Preparation. Zeolite HZSM-5 (ACS Materials, M38) was mixed as a dry powder with alumina (Sasol, Catapal D (Boehmite)) and the required amount of Milli-Q water to ensure an optimum solid-to-liquid ratio for extrusion (measured using a Mixer Torque Rheometer, Caleva). The paste, containing a ratio of 70:30 wt % zeolite:binder, was extruded using a Mini-Screw Extruder...

Caleva explain the basic Mixer Torque Rheometer concepts - Video

The MTR can process from 10g to 25 g of your material, depending on the formulation, meaning barely any material is wasted in experiments.  The machine will very quickly tell you the ideal amount of liquid to add.  The user may have a start point in mind but this may result in a formulation that is too wet or too dry.  The iterations may be repeated, but this can be wasteful in terms of...

Opportunities for Mixer Torque Rheometry

Wet granulations are a useful precursor to many solid dosage formulations and as such are widely used in the pharmaceutical industry. Because of the diverse nature of pharmaceutical materials, granulation is often employed as an intermediate process to enhance flow and compaction properties and improve the final product performance. The properties of a wet granule have a critical effect on the...

How much product should be used in the MTR and how accurate is it?

How much product do you use?  The answer is that this is always product specific. This is demonstrated in this article.  In these experiments the MTR is used in the multiple addition mode whereby increasing binder content is automatically added to different masses of product.  The Caleva Mixer Torque Rheometer. The only way to quantify the rheology of a wet mass.  The MTR has, for many years,...

Can temperature during granulation influence formulation consistency?

The temperature of the mix during granulation processes is generally considered to be of minor significance in both formulation development and in large batch granulation despite the fact that in some locations ambient temperature can change significantly during the course of a working day.The MTR manual states that the bowl should be allowed to return to room temperature after washing. The...

A Tool For Preformulation Assessment Of Excipients


Excipients from different batches or vendors may be variable in quality and it is often necessary to perform pre-formulation assessment for each batch of excipient received. In some cases, excipients from different vendors require comparative assessment of their equivalent functionality. In this type of assessment, the MTR can be an invaluable tool to evaluate the potential performance of...

How long should I granulate my materials?

Variable Mix Time Test

It is well-known that a minimum amount of mixing is required to ensure consistent and repeatable product characteristics. What is often less considered is the possibility of over-mixing the product so that the characteristics of the resulting formulation undergo a change.

How do I ensure consistency during scale up?

Consistency Measurement

A direct consistency measurement of a small sample (generally around 40 g) taken from a process as it is ongoing.  This allows for accurate comparisons to be made quickly, accurately, and repeatable way.

Formulation development - determine optimum powder to binder ratio

Multiple Addition Test

Binder liquid is added to a dry powder mix and the consistency is measured as the mixing and addition of binder progresses.

The consistency of the mix is measured at regular periods so that the relationship between the amount of liquid binder added to the mix and the consistency in the resulting formulation can be accurately shown.

What characteristics should my extrudate have?

Extrusion and spheronization is not always completely straightforward.  A formulation required for spheronization needs to go through the following processes and achieve the following properties.

How to produce consistent formulations from different mixers

Customer Quote: Mr. K.S (Aurobindo)

"It is exciting to see the correlation between the two graphs and granulation end point". 

With a major pharmaceutical manufacturer, together we characterised all their various mixers to produce a consistent formulation.

To identify three important characteristics for wet mass materials, namely:

  • The Optimum moisture point
  • The mixing time required to reach...

Do excipients purchased from different vendors behave in the same way?

The Mixer Torque Rheometer can be used to assess the behaviour of excipients purchased from different suppliers.


Excipients from different batches or vendors may be variable in quality and it is often necessary to perform pre-formulation assessment for each batch of excipient received.  In some cases, excipients from different vendors require comparative assessment of their...

The Caleva Family of Laboratory Equipment

Whilst you may have heard of Caleva and any one of its flagship pieces of equipment, we'd like to introduce you to the family of Caleva laboratory equipment that you may find helpful for your application in your industry sector.  Choose one process or choose all of them.  Select further functions as you need them.  This adaptable and future proof suite of equipment will allow you to obtain...

Inconsistent spheronization results with difficult active ingredient?

The following case study demonstrates how the Caleva Mixer Torque Rheometer.  The MTR-3 was an invaluable aid in a specific case. A manufacturer of generic Venlafaxine pellets was experiencing inconsistent results from their manufacturing line. The resultant product was variable in both usable yield (weight of acceptable pellets as a % of weight of granulation made), and dissolution profile....

Mixer Torque Rheometer used with Food Powders

Research Article University of Padova where their Caleva Rheometer was used

The Importance of End Point Detection Consistency

This world is not only for us. Can you imagine world had no animals, what would it be like? Would the trees be green? Without birds or squirrels, less trees would grow. There would be no pets, no flowers and no bees. If even one part of our ecosystem is removed, we will all die. Without animals, we will surely go extinct.

Caleva Multi Lab & Bone Regeneration study Medical University Gdańsk

Drug-loaded mesoporous silica/calcium phosphate composites for bone regeneration

Adrian Szewczyk at Department of Physical Chemistry, Faculty of Pharmacy, Medical University of Gdańsk has kindly allowed us to introduce this paper that introduces a study of Drug-loaded mesoporous silica/calcium phosphate composites for bone regeneration.  


Agglomeration properties of gluten-free flours under water addition and shearing conditions

The different states of agglomeration were identified by the evolution of rheological properties under water addition and shearing conditions using a Caleva® mixer torque rheometer. 

How reproducible can measurements be of something that is not homogeneous?

The MTR-3 uniquely offers a means of characterising the rheological properties of a wet granulation by providing a quantitative value of the consistency of the material tested. The more traditional hand squeeze test, previously widely used, to measure or compare granulations, is falling into disrepute and is no longer considered appropriate for modern day industrial production or research...

Yield problems in production and quality control

One of the strengths of the Caleva Mixer Torque Rheometer (MTR-3) is that it can be used to verify the properties of wet powder mass samples taken during production in large scale mixer/granulator systems. It can be used simply as a quality control tool on a regular basis or specifically as an aid to problem solving. Small samples can be taken directly from production and within two minutes a...