Crystal Miranda ^a, Colleen Neu ^b, Jerry Klinzing ^b 

^a Merck & Co., Inc., Rahway, NJ, USA 
^b Merck & Co., Inc., West Point, PA, USA 

Purpose. One type of scaling method for compression is to match the maximum punch velocity to better reproduce tablet performance. This methodology is based on previous studies conducted on a compaction simulator. The goal of this study is to validate the punch velocity scaling model on a variety of tablet presses. 

Methods. Two drug products, “A” and “B,” were selected to assess the scalability across two presses. Product A is not expected to be strain-rate sensitive, whereas Product B is expected to be sensitive. 

Compaction profiles were generated on each press for each product at several press speeds. The compression turret speed was scaled by matching the theoretical maximum pre-compression punch velocity. The theoretical value is a calculation based on press and tooling geometries. Tabletability and disintegration were used as the key product attributes to assess scalability. 

The Intelli-punch, an instrumented punch, was used to measure the displacement profile of the upper and lower punches to generate the actual punch velocity profile. The measured velocity values were compared against the theoretical values to determine if a correction factor need be applied during analysis. 

Results. The study confirmed that scaling by pre-compression punch velocity results in comparable tabletability and disintegration for both Product A and B. In addition, the Intelli-punch demonstrated that the actual pre-compression punch velocity is higher than the theoretical velocity, so a correction factor is needed for future use of the theoretical calculator.  

Conclusions. The punch velocity scaling methodology has been validated by two products across two tablet presses. In addition, the Intelli-punch was proven effective in measuring the accurate punch velocities experienced by the product during compression.