Jerome B. Johnson

  • Jerome B. Johnson

 Mechanistic DEM model of tablet compaction and detachment to assess punch sticking risk

Punch sticking risk during tablet manufacture of new formulations is difficult to assess given the limited amount of tablet compaction data available prior to moving to full tablet production runs. One method to improve risk assessment of punch sticking is to use a mechanistic DEM punch sticking model of tablet compaction and detachment, taking into account the cohesive and adhesive properties of the formulation constituents with each other, the punch, and die sidewall. Model calibration is done from diametral tension strength measurements of API, Excipient, and formulation and simulation of adhesion between API and excipient (Paul and Sun, 2018, Paul, 2019). Punch/API adhesion at the transition from no sticking to sticking is the minimum adhesion required to pull API from the tablet matrix (σ_PAm^a). Measurements of the amount of API that sticks to a punch during one or more compression cycles is the punch specific adhesion required to pull API from the tablet matrix (σ_PAp^a). The model was verification by comparing model predicted punch sticking risk with Paul and Sun’s (2018) data. Model results predict that punch sticking increases with increasing w/w% API load in a formulation and with decreasing particle size. Punch sticking decreases with increasing excipient cohesion and punch/API adhesion. Punch sticking can be reduced by careful selection of excipient properties.

Bio Sketch:

Dr. Jerome (Jerry) Johnson has degrees in physics, mathematics, and geophysics (Ph.D.). He has over 35 years of applied research solving problems of Artic infrastructure and engineering, military operations, space exploration and engineering, and resource utilization for government, academia, and the private sector. Dr. Johnson led individual and large team projects to determine ice forces on offshore structures, snow effects on mine neutralization, tools to find resources on the moon, the physics of tire/snow interaction, constraints to Mars rover mobility, penetration in granular materials, and renewable marine energy. He was director of the Alaska Hydrokinetic Energy Research Center and participating scientist on the Mars Polar Lander and Mars Exploration Rovers NASA missions. He is a Co-I on the CAESAR comet sample return mission proposal to analyze the performance of the sample acquisition system. He co-developed, with Anton Kulchitsky, the Polyphysica particle dynamics model and is an expert on granular media mechanics. Dr. Johnson is currently an adjunct research professor at the University of Alaska and CEO of Coupi, Inc.