Q: What issues can tablet sticking cause during pharmaceutical manufacturing, and how well understood is this problem?
A common way of reducing sticking is to slow the tablet press down, thus increasing the dwell time. However, this solution is unpopular with tablet manufacturers because it reduces productivity of the tablet press. As a consequence, tablet press manufacturers and tablet tooling manufacturers have introduced solutions to help the end-user reduce sticking issues in production. For instance, I Holland has developed a range of antistick coatings that have been successful in solving sticking, but the coating used should always be matched to the specific formulation. In the past we have worked in partnership with our customers to carry out trials using all the antistick coating solutions in order to match the correct coating with the formulation and environmental conditions. A potential issue with this method is the associated cost incurred in time and expense to find the correct solution.
Q: With a variety of ingredients used in manufacturing, it must be difficult to systematically benchmark sticking behaviour for each ingredient. Can you talk about how the new collaboration between I Holland and the University of Nottingham aims to tackle this issue?
This is an important question and is in fact also complicated by orientation effects because the same material (if crystalline) can present quite different surface properties (chemical and mechanical) depending on preferential orientation effects. However, whilst building a library of data will take time, the range of excipients used in most formulations is not actually so extensive with the same materials (albeit in slightly different forms) often being used, particularly, with the high percentage content of solid dosage forms. Of course, APIs will be different and we will deal with the ones known to cause the most problems first and attempt to cluster compounds that have similar properties. Ultimately, the intention is to have a model that can predict sticking to various punch surfaces not based upon complex analytical measurements, but on a limited set of parameters that may largely already be known.