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Better Prediction and Control of Drug Release Is Achieved by Using Terahertz Imaging to Map Tablet Coating Thickness and Density

TeraView Ltd is the pioneer and leader in terahertz solutions and technology for the pharmaceutical and life science industry. A recent study published by the US Food and Drug Administration noted that the speed and ease of terahertz imaging could make it a viable replacement for wet dissolution testing. This FDA investigation has been further corroborated by a new study by the Universities of Dusseldorf and Otago.

In the FDA publication, terahertz imaging was used to accurately map the coating thickness and mean dissolution times were found to correlate with the average tablet coating thickness, suggesting that the coating thickness played a significant role in product design and performance.

This recent study has now identified that to get a better predictor and monitor of dissolution characteristics, coating thickness should be measured in combination with coating density.

The Dusseldorf/Otago research has demonstrated the unique ability of terahertz imaging:

  • to measure and map coating density across the surface of a tablet
  • show that for some coatings, particularly those that act as semi permeable membranes, density of the coating can be a more powerful indicator of dissolution time than coating thickness which does not take in to account the porosity of the coating that may result from non optimised coating conditions
  • to provide a key performance indicator that can be used to more successfully scale-up a sustained release product than the usual non direct measurement of weight gain.

Modified release coatings can be difficult to scale-up due to the need to change process parameters as well as batch size. Until the development of terahertz pulsed imaging (TPI) by TeraView there has not been a method to directly and non-destructively assess the impact of changing process conditions on coating critical quality attributes such as coating thickness, density and porosity, and establish the uniformity of these across the tablet surface.

Dr Don Arnone, Chief Executive Officer of TeraView commented: “This study reinforces the use of terahertz solutions to address issues in solid dosage form development. Its successful application in the scale up of modified release coatings is unique and not replicated by any other existing techniques”. Don Arnone added ” These capabilities deliver significant business benefits for our customers through accelerated development of new products, as well as helping to ensure that these products remain in-spec and compliant once they are on the market”.

Note for editors
This study is published in the Journal of Controlled Release in April 2008 (Volume 127, Issue 1, 7 April, pages 79-87). Previous studies, including the FDA’s “Delayed Release Tablet Dissolution Related To Coating Thickness By Terahertz Pulsed Image Mapping” have been published in the Journal of Pharmaceutical Sciences and other leading pharmaceutical journals.

Terahertz light is unique in its ability to non-destructively image tablets and other dosage forms. X-ray and infrared frequently lack sensitivity or penetration and cannot produce such images without first destroying the tablet. TeraView currently works closely with blue chip customers in the pharmaceutical industry who are exploring the use of terahertz in product and process development and quality control of finished product in manufacturing.

About TeraView (www.teraview.com)
TeraView is the world’s first company devoted to the application of terahertz light for spectroscopy and imaging in pharmaceutical drug development and manufacture. TeraView’s technology can improve the quality of pharmaceutical products and decrease the risk of regulatory non-compliance, leading to potentially safer tablets and savings arising from faster times to market and volume production of higher quality, stable products. Other markets for the technology exist in early stage cancer detection, defence and industrial inspection which are explored via commercial partners. Headquartered in Cambridge, UK, TeraView was spun-out of the Toshiba Cambridge Research Laboratory in April 2001. Sales and support are available throughout Europe, North America and the Far East either directly or through a network of distributors.