(76e) Diagnostic Tools for Stickiness Evaluation

Picking and sticking, the adherence of material to punch surfaces during tableting, may pose serious production problems such as reduced efficiency and irregularly formed tablets. Though it is generally believed that sticking is caused by favorable intermolecular interactions between drug molecules and the punch face, it is difficult to predict when and how sticking will occur throughout compaction. In this study, two small-scale diagnostic tools were designed to evaluate the sticking tendency of drug formulations. First, the adhesion phenomenon was investigated utilizing a single particle impact tester to assess the attractive force between drug particles and a metal surface (150 mg scale). The second method involved compressing tablets on the Carver press using embossed tooling (1 g scale). The punch faces were evaluated with a microscope after compression. The sticking tendencies obtained from these tools were in accordance with the large-scale performance of these materials. The methods were also applied to two studies that investigated the effect of the lubricants magnesium stearate and sodium stearyl fumarate on sticking. In both tests, lubricant was found to decrease the sticking tendency of formulations. Magnesium stearate appeared to coat drug particles more evenly while sodium stearyl fumarate seemed to adhere to the metal surface more strongly.