Effect of compression force, compression speed, and particle size on the compression properties of paracetamol

The compression characteristics of two particle size fractions ( < 90 <mu>m , 105-210 mum) of paracetamol were examined. Each fraction produced extreme ly weak tablets and displayed a high tendency to cap. Low correlation coeff icients of the initial parts of the Heckel plots, a low strain rate sensiti vity, and an increase in mean yield pressure (from 34.2 to 45.5 MPa) with d ecrease in particle size all confirmed that the main mechanism during the c ompaction of paracetamol was fragmentation. The 105-210-mum particles under went more fragmentation than the less than 90-mum powder. Heckel analysis c onfirmed that the larger size fraction of paracetamol produced denser compa cts than the smaller fraction. The 105-210-mum fraction resulted in tablets with lower elastic recoveries and elastic energies. The elastic : plastic energy ratios indicated that the majority of energy involved during the com paction of paracetamol was utilized as elastic energy, indicative of massiv e elastic deformation of paracetamol particles under pressure.