Definition of Rheometer:
properties of a material. Meter measure and quantify.
Introduction to the Caleva Mixer Torque Rheometer
The Caleva Mixer
The Caleva Mixer Torque Rheometer is a useful research
and quality control tool.
The Mixer Torque Rheometer (MTR) is used for
investigation of the properties of wet masses and the study
of binder substrate interactions.
MTR offers a means to scientifically explain, predict,
screen and characterize WET MASSING processes/materials
used in the following stages for the development and
production of Pharmaceutical Solid Dosage Forms:
- Wet Granulation
- It should be small scale, portable and easily
- It should be interfaced with a personal computer for
ease of use and recording.
- It should produce a repeatable output directly
related to the rheology of the wet mass.
- It should have the ability to be calibrated
- It should be variable in mixing speed.
- It should have a water jacket for temperature
- It should be easy to use
The Caleva MTR: What can it do for you?
- For investigation of the granulation process
- For investigation of binder-substrate
- For investigation of formulation suitability for
- To check source and/or batch variations
- To quantify the suitability of different binder
- To investigate the effects of different mixing
- To monitor production scale granulation for quality
- To quantify pseudo viscosity measurements for scale
Basic Configuration of the MTR
MTR Blades and Bowl
The MTR is basically an instrumented, small capacity,
twin blade, high shear shear mixer. The torque from the
rotating blades exerts a force on a load cell by the
reaction of the bowl to the turning blades. An attached
personal computer running the Windows based MTR software
records the force imparted on the load cell.
The MTR for Research:
1. Basic investigation of the wet granulation and
Torque vs. Binder
- All substrate binder mixes studied using the MTR have
exhibited quantifiable changes in torque values with
increasing water content.
- The level of saturation can be investigated and an
optimum mix ratio easily identified for any
- You can insure that the studies on basic processes
with new materials can be investigated quickly in a
quantitative and repeatable way.
Investigation of binder-substrate interactions
Different Torque Curve
for Different Binders
- Investigations to examine the granulation process can
be further refined by replacing the water with different
types of polymer binders.
- Different binders can quickly be evaluated for their
- These differences in interactions demonstrated by the
MTR clearly have implication on the binder selection
process in any research program where binder substrate
interactions are being studied.
The MTR for Formulation Devlopment
To check source and/or batch variations in
Different Torque Curve
for MCC from Three
- An example of profiles for MCC (Micro Crystaline
Cellelouse) from different sources
Source variation in constituents of a formulation
Different Torque Curve
for MCC from Two
- Materials from different batches can lead to problems
in formulation development.
- The results show different torque properties that can
be obtained with the same material from different
- These results can give the formulation different
- Consistently good formulations can be insured with
the MTR even when the source of the ingredients can
To Quantify The Suitability of Different Binder
Different Torque Curves
- In general, increasing binder concentration results
in stronger tablets.
- The MTR can be used to quantify the effect of
increasing binder on the strength of the final
- Further work would be able to relate the observed
results produced by the MTR to the granulation and
compaction strengths so that both formulation costs and
quality can be optimized.
Different Mixing Time
- Mixing time is a critical factor in the granulation
- The MTR is the only way to quickly examine a range of
parameters to assess their effect on the granulation end
- Mixing time requirements to have the optimum
formulation can vary with the binder volume added.
- The MTR can be used to investigate the effect of
mixing time on wet masses to insure the best
granulation/extrusion properties of the formulation.
Monitoring Production Scale Granulation for Process
- The MTR is an ideal instrument for monitoring
production scale mixing because it uses such small sample
sizes and produces results very quickly.
- Of the 45 samples that were examined from different
mixing batches in the example shown, the majority fall
within acceptable levels but some clearly did not.
- Necessary remedial action can be taken quickly!
- In the quality control inspections of samples from
the manufacturing process batches can quickly be
identified that have unacceptable characteristics.
- The MTR is an invaluable (and potentially money
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