Knowledge Base

Extrusion of small batches

The Caleva Multi-Lab (CML) can Mix/Granulate, Extrude and Spheronize all in one base unit.

This article is about the Extruder attachment that comes with the CML.

The Multi-lab is capable of working with a variety of materials from catalysts and pharmaceuticals, to agricultural products.

The Extruder

The extrusion attachment on the CML is in the form of a single screw extruder.  A variety of...

Possible issues with extrusion of small samples - how to resolve them

It is not possible to extrude and spheronize everything.  Extrusion and spheronization can be used on a wide range of products and formulations.  However, if you are having trouble extruding your formulations with the Caleva Multi Lab (CML) then please read this article.

Caleva offers extruder screws of different designs for use with the CML.  If you are having issues with the CML then the...

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...

Extruder dies | all sizes | variable density | quadrilobe | trilobe

In the process of extrusion, having different dies available to process your product is key to increasing your chances of development success.  This is why we offer a large range of dies to allow us to work with you to find the dies that best fit your formulation needs.

We offer die plates that are excellent for most uses, like our 1 x 1 mm die, however sometimes a more specialist die may be...

A better way to granulate with your viscous and sticky materials

Our new High Viscosity Mixing Blades, designed for making those sticky, viscous, difficult, granulations much simpler.  Our design team have been working tirelessly to come up with a solution to a constantly asked question. 

Extrusion of catalyst and petrochemical materials

An opportunity in laboratory extrusion with catalyst material.  We have recently had some considerable success with one of our customers working with the extrusion of small quantities of catalytic material.

Extruding catalyst materials for petrochemical and adsorption products

In collaboration with some of its users, Caleva have recently been successful in extruding of small quantities of catalytic material using the Caleva Multi Lab (the first steps of blending and mixing can also be completed in the same multilevel base machine) whilst increasing the surface area/volume ratio of the extrudate produced.

The Caleva Multi Lab is faster and easier to clean

The Caleva Multi Lab (CML) is faster and easier to clean than any comparable bench-top extrusion & spheronization equipment.

The best results in the minimum time for your formulation development


Guide to the optimum diameter to length ratio of extrudate fragments

Is there a guide to the optimum Length to Diameter ratio of the extrudate fragments?

In the calculations used to demonstrate the data it is assumed that the extrudate is an infinitely long strand. In this case the length of the extrudate has no influence on the data shown. In reality, extrudate is not infinitely long and as the individual strands of the extrudate produced become shorter, the...

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 type of pharmaceutical or catalyst extruder do I need?

All extrusion processes require the generation of pressure within the material to be extruded. When materials are put under pressure heat is generated. This cannot be avoided but different extrusion types generate different amounts of heat. There are basically three different types of extruder and the one chosen may have far reaching implications on production operations. It is important that...

What pharmaceutical products or drugs can I make in pellet form?

A list of suggested uses for pellets in pharmaceutical applications. 

We are working closely with many partners in a wide variety of industries as well as pharmaceutical. The industries where we are helping our customers to make pellets and extrudates are listed below. 


What is the smallest particle that I can coat in the Mini Coater Dryer

The Caleva MCD was originally designed for coating of very small batches of tablets. The original Mini Coater Drier was very efficient at this. However, as a response to several user comments and requests a new version was designed to allow users to also coat small samples of pellets over a range of industries.  The original improved design specification that users were requesting was that...

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.