A material sparing method for quantitatively measuring tablet sticking

The aim of this study was to develop a material-sparing method to quantitatively measure sticking during tablet manufacturing and to allow direct comparison of blends in terms of sticking. A protocol has been developed for quantitation of API layering on punch faces using HPLC analysis. Tabletting runs were carried out such that different numbers of tablets were produced by each punch set. The punch faces were quantitatively extracted and the concentration of API in the extraction solutions was determined by HPLC analysis. The amount of API on the punch faces increases linearly with the number of tablets produced (cycles). This relationship has been demonstrated on both a single station press (Fette) and on a rotary press (Riva, Piccola) and for a number of different API blends. The method was used to study the impact of MCC grade, lubricant concentration and solid fraction on sticking behavior. With all other variables constant, blends with Vivapur 102 as filler showed more layering than blends with Avicel PH 102 as filler. Increased solid fraction and increased MgSt concentration led to decreased API layering. The elemental make-up of the material adhered to the punch face was characterized by SEM/EDS analysis and was compared to the elemental make-up of the blend. The material adhered to the punch surface was enriched in API and silicon dioxide (SiO₂) relative to the blend.