Influence of tableting forces and lubricant concentration on the adhesion strength in complex layer tablets

The strength of adhesion in complex two-layer tablets is assessed using sta tistical methods wit respect to the applied tableting forces for the first layer and for applying the second layer on the first, as well as regarding the fraction of the lubricant. These results, obtained on a single-punch ta blet press, are compared with the results for three-layer tablets produced on a rotary press at production scale. The strongest negative influence on adhesion strength was exerted the amount of lubricant in the central layer. As expected, compression forces for central-layer tableting also had a neg ative effect, whereas the compression forces for complex layer tableting ex erted a positive effect on layer adhesion. The validity of the derived mode l equation was proved by experiments: It was shown that the adhesion streng th in complex layer tablets produced in production scale can be predicted f rom laboratory-scale experiments. This makes optimization of the formulatio n and parameter settings at an early stage of development possible.