Understanding the Factors That Control the Quality of Mini-Tablet Compression: Flow, Particle Size, and Tooling Dimension

Despite the increasing importance of mini-tablet for its advantages as pediatric formulations and in modified-release applications, its popularity is limited due to the lack of formulation and processing knowledge in developing such dosage forms. In this study, common grades of microcrystalline cellulose and roller compacted granules with a range of powder properties were used to evaluate the critical material properties required for the successful manufacturing of 1.7-mm mini-tablets. It was found that blends with small particle size had poor flow properties that did not support consistent die filling and also tended to cause tooling jam and damage. While the granulation process was effective in improving blend flow properties by increasing particle size, it is imperative to avoid very large particles that could also cause inadequate flow by blocking the space within the die. Successful mini-tablet compression could be achieved by removing particles larger than roughly 1/3 of the die diameter or milling the granules using a screen less than 1/3 of the die diameter.