Compression characteristics of some pharmaceutical materials

Abstract

A commercial single-punch tablet machine (Manesty E 2) fitted with 1/2-in. punches was instrumented with strain gauges to monitor the forces simultaneously on the upper punch and the die-wall. The complete pressure cycles of a number of pharmaceutical materials at various levels of compression have been studied. The materials were sucrose granules and crystals, acetaminophen granules, aspirin crystals, and sodium chloride crystals. It has been found that these materials conform to three different types of compression pattern. The results indicate that materials which laminate on compression behave like a Mohr's body, e.g., acetaminophen granules without binder. Granulation of acetaminophen with polyvinylpyrrolidone altered the compression pattern to that of a body with a constant yield stress. Aspirin compacts were found to exhibit elastic properties. Compression patterns are given for 20/40 mesh and 40/60 mesh crystals and granules of sucrose. No significant differences due to particle size were found, but differences were noted between the crystals and granules. The poisson ratios of these materials are given. A commercial single-punch tablet machine (Manesty E 2) fitted with 1/2-in. punches was instrumented with strain gauges to monitor the forces simultaneously on the upper punch and the die-wall. The complete pressure cycles of a number of pharmaceutical materials at various levels of compression have been studied. The materials were sucrose granules and crystals, acetaminophen granules, aspirin crystals, and sodium chloride crystals. It has been found that these materials conform to three different types of compression pattern. The results indicate that materials which laminate on compression behave like a Mohr's body, e.g., acetaminophen granules without binder. Granulation of acetaminophen with polyvinylpyrrolidone altered the compression pattern to that of a body with a constant yield stress. Aspirin compacts were found to exhibit elastic properties. Compression patterns are given for 20/40 mesh and 40/60 mesh crystals and granules of sucrose. No significant differences due to particle size were found, but differences were noted between the crystals and granules. The poisson ratios of these materials are given.