Quality by design (QbD) approaches for the compression step of tableting.

INTRODUCTION: Although tableting is one of the most commonly used processes in drug manufacturing, the tablet formation process is still not fully understood, nor can it be fully controlled. AREAS COVERED: In this paper, recent approaches to correlate tablet mechanical properties with process parameters are discussed, covering (mainly) the last 5 years. These approaches are the basis for a future of rational formulation strategies, which may lead to optimum tablet properties within a shorter timescale, in contrast to the present empirical approach. The reader will on one hand gain an insight into current parameterization of the tableting process and evaluation strategies and on the other hand will gain an impression of the difficulties connected to the interpretation of a physically complex process and its impact on predictive modeling. EXPERT OPINION: The main consolidated findings are that even when using multivariate statistical approaches, it cannot be expected to find a global evaluation method that fully explains the mechanism of tableting, but that careful sequential evaluation is required. For further improvement, there is a need to use more complex models and alternative technologies, in order to increase both tablet quality and productivity.