Tablets & Capsules


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Tablets & Capsules September 2014 29 In 2012, British tooling manufac- turer I Holland launched its TSAR (Tabletting Science Anti-Stick Re - search) program, a 2-year project aimed at solving one of the most per- vasive and confounding tabletting problems: sticking. Last February, the company unveiled the result—its TSAR-Predict service, an algorithmic predictive model that quickly calcu- lates the optimal anti-stick coating to apply to compression tooling based on the properties and characteristics of its customers' formulations. According to Rob Blanchard, re - search and development manager at I Holland and a key player in the pro- ject, "The predictive model allows us to enter parameter information and very quickly identify the best punch or die coating for sticky formulations, elimi- nating in most cases the need to con- duct slow and costly in-the-field test- ing. All we need is the name of the API or main components of the formula- tion." In cases where the API is confi- dential, "we can work with the basic characteristic information on key physical properties to come up with a solution," Blanchard said. The science of sticking "Understanding the factors that lead to sticking is what we did to develop our PharmaCote range of coatings, long before TSAR began," Blanchard said. "The objective was that if we could understand what causes sticking, we could tailor coatings for punch-tip faces to prevent it. Our tabletting science team tackled that, and we've got a proven range of anti- stick technologies as a result of that research. But the one thing needing improvement across the industry was the ability to select the right coating solution more quickly. And that's what TSAR-Predict is really about," he said. Blanchard noted that a number of complex, interrelated factors cause sticking. These include Van der Waals forces—the weak, nanonewton- strength forces of molecular attraction between formulation particles and punch-tip surfaces that cumulatively promote sticking. Other causes in - clude capillary action (or "wicking") associated with high moisture content or, conversely, clinging due to static electricity generated in very dry con- ditions. [Editor's note: For more informa- tion about the causes of sticking and how I Holland conducted its tests, see the July 2013 issue, p. 40.] Because the physical properties of any sticky formulation are unique, there is no one-size-fits-all anti-stick solution. The goal was to identify which specific coating to use with a given formulation. "To get to the stage of producing a predictive tool, we be - gan by making tablets with a variety of excipients and APIs using a number of anti-stick coatings and our Pharma - Grade range of tooling metals," Blan - chard said. "For instance, we carried out a case study using ibuprofen, a notoriously sticky formulation. When the research team's analytical techniques correctly predicted which coating actually worked best to prevent sticking on a tablet press, it validated the concept of our predictive tool." From there, blind trials using different formulations sup- plied by the company's international customers could begin. "From these tests, we built up a database of results. As well as carrying out compression trials, we also ran a lot of analysis using very complex techniques" (specifically, atomic force mi croscopy and time-of-flight sec- ondary ion mass spectrometry). "We also did adhesion mapping using those techniques to look at particles stuck to a punch tip and analyze ex - actly what they are chemically, thus work ing out what those interactions are." Getting unstuck The database that emerged from this research is used to continually hone the accuracy of the TSAR- Predict service, now offered free of charge to the company's customers. Prior to predictive modeling, deter- mining which coating to use was a costly, time-consuming process that in volved trying out several tooling sta- tions treated with different coatings at the customer's site to see which worked best. Such trial-and-error case studies could take as long as 6 months (Figure 1). With TSAR-Predict, once process para meters such as surface chemistry, temperature, humidity, and granule size are entered, a coating rec- ommendation is nearly instantaneous. "It's a first in the industry," Blan - chard said, "and this has caught the attention of major manufacturers who are using the model to resolve prob- lems which previously would have required down-time." T&C I Holland Americas, Fort Myers, FL. Tel: 800 420 2991 I Holland's TSAR-Predict forecasts faster fixes for sticking problems Figure 1 The conventional trial-and-error method of identifying the right anti-stick coating can take 6 months. Using TSAR-Predict modeling, I Holland can do it rapidly, in silico. Customer requests support 1 I Holland recommends selection of coatings based on historical performance 2 Design punch tips so we can identify which coating works from looking at tablets 3 Quotation prepared for full coating test set 4 Order placed for full set of all anti-stick coatings 5 Tooling manufactured 6 Tolling shipped to customer 7 Secure time on tablet press for compression trials 8 Complete compression trials 9 Review results 10 Issue report 11 Correct anti-stick coating identified 12

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