Predicting Dissolution with Tablet Imaging

Terahertz peak amplitude can be used as a measurement of coating density and as an indicator of dissolution (Figure 1).

Predicting Dissolution

It is used to maintain and ensure in-specification performance during scale up of a sustained release product.  The measurement takes into account the porosity of the coating, unlike coating weight gain.

Predicting dissolution through tablet imaging

Terahertz imaging shows why tablets coated to release drug in lower intestinal tract are dissolving in an erratic fashion (Figure 2). The mean dissolution time correlates to the terahertz measurement for coating thickness. Terahertz imaging offers a potentially faster method for determining variation in dissolution rates.

Figure 1. As mean dissolution time (MDT) changes during scale-up this is reflected in the terahertz coating thickness.

Controlling process transfer of a multi-layer tablet

Terahertz imaging non-destructively measures the buried interface between two layers of a bi-layer product (Figure 3). The measurement allows the formulation and compression parameters to be optimised for improved adhesion between the layers in the tablet core.

Figure 2. Terahertz imaging maps the coating thickness, uniformity and region of failure.

Tablet Imaging

Defining the compression process window for an anti-viral product

Terahertz tablet imaging identifies compression process limits for the manufacture of a tablet prone to latent capping. Virtual cross sections of the tablet reveal those compression parameters that cause cracking (yellow red areas in Figure 4) deep in the tablet core. As a result the compression parameters could be more accurately defined to ensure high quality of the finished product.

Figure 3. Images of the buried interface between the two API layers in a tablet show the variation in adhesion. Thebottom tablet exhibits very poor adhesion between the two layers.

Conclusions

Terahertz pulsed imaging (TPI) can accurately and non-destructively develop robust product and processes control for scale up to manufacture. It can monitor product attributes affecting stability and design, as well as predict, changes in drug release profiles.

Figure 4. Non destructive cross-sections clearly identify cracks at depth within the tablet core. Top images show goodquality tablets, bottom images show tablets with integrity problems.

For further information on terahertz spectroscopy and on our testing service please visit the website. You can call us at +44 1223 435380 or, Contact Us.

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