BIND, a novel analytical approach for monitoring powder adhesion at the die wall with use of the surface replication method.

Tableting failure due to binding is often caused by powder adhesion to the die wall. The present study was undertaken to develop a novel approach for analyzing the binding characteristics of various formulations and manufacturing methods, named "Binding Identification for Net Detriment" (BIND). Binding characteristics with raloxifene hydrochloride as a model preparation were evaluated by visual observation, ejection force and BIND. The surface replication method was initially employed to monitor powder adhesion to the die wall. Microscopic images with replicates were analyzed qualitatively and quantitatively. For the validation, BIND and measurement of the friction between a tablet and the die wall were performed. The qualitative data on BIND agreed with visual observations; however, there were some data discrepancies between the ejection force and visual observations. For the formulation without lubricant, BIND showed a 30.2% powder adhesion rate, while the formulation containing 1% lubricant exhibited a powder adhesion rate of 4.1%. Thus, BIND demonstrated that the use of the wet tableting method reduced powder adhesion compared with the direct tableting method. BIND allowed qualitative and quantitative analysis of powder adhesion for both powder compression and tablet ejection. BIND is a promising tool for analyzing powder adhesion to the die wall.