How to measure and analyse the texture of food, cosmetics, pharmaceuticals and adhesives.

Monday, 19 June 2017

Texture Analysis in Sports Nutrition – Hydrating and maintaining hydration with hydrotabs

Low Tolerance Powder Compaction test of a tablet
using the TA.XTplus Texture Analyser
Hydrotabs are specifically designed sports rehydration tablets that ensure fast hydration during intense exercise. 

These quickly dissolved tablets are packed with electrolytes and are high in sodium (and usually containing other electrolytes) to further promote the hydration process.

Compact solution
Many products are produced in powder format and then compressed into tablets. Powder compaction is an essential step in the manufacturing process and it is essential to avoid products cracking during processing. 

Their liability to failure is influenced by the powder’s processing properties, such as density variations introduced during die filling and/or compaction. 

The characterisation of powder in its bulk format can enable manufacturers to predict the behaviour of the powder when compressed; however, the need for more targeted analysis of powder compaction has been identified and, as a result, the Powder Compaction Rig was developed. 

Available in High or Low Tolerance variants, this rig accurately measures the force and/or punch displacement required to compress powders into tablets. Using Exponent software, the Powder Compaction Rig produces precise measurements that enable pharmaceutical product manufacturers to produce powder compacts with consistent porosity. It accurately assesses the force needed for the punch to travel a specified distance, or can be used in target force mode to assess the effect of fill level on tablet thickness.  

The High Tolerance Powder Compaction Rig is suited to high force applications where the punch/die clearance is critical. This fixture is auto-aligned using a universal adapter, which saves time and avoids human error. The Low Tolerance version is suited to other powder compaction applications, such as assessing granule friability, where punch/die clearance is less important.

Measuring Tablet Failure via Diametral Compression
Tablets must be sufficiently strong to withstand the rigours of processing and manufacturing, as well as packing and transport, but also be capable of dissolving easily – thereby delivering the required electrolyte source to the consumer.  

Diametral compression test of a tablet using the
TA.XTplus Texture Analyser with Shatter Screen
Tensile strength is a good indicator of a tablet’s robustness and there are various ways to measure this. As tablets usually fracture along the diameter, diametral compression – where the sample is compressed from both sides – is a commonly used method. The TA.XTplus and TA.HDplus texture analysers are widely used to perform these diametral crushing tests. 

The maximum force value, i.e. the peak as indicated, is the force required to cause initial mechanical failure of the tablet, which is followed by further breakdown. From these results, the area under the force applied versus tablet deformation can be calculated as the work of failure and related to the toughness of the tablet (see graph below). 

Typical Exponent curve of a diametral
compression test of a tablet
This diametral crush test identifies important characteristics missed by conventional tablet strength testers, which only measure the force point at which the tablet breaks. Such measurements are widely used both for in-process monitoring and quality assurance testing at the end of production.

A formulation generally has to satisfy a number of demands; for example, an increase in crushing strength may result in prolonged disintegration time. Therefore, a compromise, rather than an optimum, solution to the formulation goals must be accepted.  In many cases, the supposed optimum composition is found by trial and error – a formulation is drawn up and subsequently tested. Should the formulation properties not meet the specified requirements, changes are made in the composition of the excipients in the formulation or the process variables, until the desired properties are obtained.  

Tablet breakdown

The rising popularity of fast dissolving tablet forms can be attributed to convenience and the ease of delivery they offer.  A thorough analysis of disintegration behaviour is vital for the formulation of new dissolving tablets to ensure reliable and breakdown. The tablet has to be resilient enough to endure manufacturing and shipping yet release a sufficient amount of disintegrants to deliver an optimum dissolution rate.

A Tablet Disintegration Rig attached to a TA.XTplus texture analyser facilitates the reliable assessment of the mechanical properties of fast-melting tablets. The rig closely replicates the in vivo conditions of the human mouth, enabling manufacturers to examine water absorption and the disintegration of associated particles into individual components. 

This allows the determination of tablet disintegration time and behaviour, giving a valuable insight into performance and efficacy (see graph below).

Typical Exponent curve of a diametral
compression test of a tablet
The unique geometry of the rig allows the disintegration medium to access the tablet from all areas. The dry tablet sample is secured to a probe by a thin strip of double sided adhesive tape along its diameter. The probe’s surface has a ‘channelled’ design, allowing fluid to flow freely all round the tablet while ensuring contact is maintained with the probe. 

Once the probe is lowered into the medium, the tablet is positioned on a perforated platform, and the texture analyser applies a constant force onto it. The perforated surface enables free ingress of water beneath the sample and dispersion of the disintegrant.

Request our article Texture Analysis in Sports Nutrition which looks at developments in testing for this growing product sector.

We can design and manufacture probes or fixtures for the TA.XTplus texture analyser that are bespoke to your sample and its specific measurement.

Once your measurement is performed, our expertise in its graphical interpretation is unparalleled. Not only can we develop the most suitable and accurate method for the testing of your sample, but we can also prepare analysis procedures that obtain the desired parameters from your curve and drop them into a spreadsheet or report designed around your requirements.

For more information on how to measure texture, please visit the Texture Analysis Properties section on our website.

TA.XTplus texture analyser with bloom jar The
TA.XTplus texture analyser is part of a family of texture analysis instruments and equipment from Stable Micro Systems. An extensive portfolio of specialist attachments is available to measure and analyse the textural properties of a huge range of food products. Our technical experts can also custom design instrument fixtures according to individual specifications.

No-one understands texture analysis like we do!

To discuss your specific test requirements click here...

Watch our video about texture analysis Replicating Consumer Preferences
 Texture Analysis applications

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