Sticking of material to tablet punch surfaces is a common problem encountered during tablet development. We have developed a method for quantitation of API layering on punch surfaces using HPLC analysis. Additionally, SEM/EDS was used to track the distribution of excipients and API in the blend and on the punch face after compression (1). We have shown that the amount of API adhered to punch surfaces increases linearly with the number of tablets produced (cycles). This relationship has been demonstrated for a number of different API blends and process conditions. The method has been used to study the impact of API characteristics, lubricant level, solid fraction, and glidant on sticking behavior. It is well known that lubricant level and solid fraction (compression force) impact the extent of sticking observed (2). However, the sensitivity of our method allows the impact of small changes in the formulation to be tracked and has led to some surprising insight into the role of excipients and excipient interactions in tablet sticking.