POROSITY PARAMETERS OF LACTOSE, GLUCOSE AND MANNITOL TABLETS OBTAINEDBY MERCURY POROSIMETRY

The effect of compression force, compression speed and the amount of g ranulation liquid on the porosity parameters determined from lactose, glucose and mannitol tablets by high-pressure mercury porosimetry was investigated. Compression force affected all parameters measured, exce pt the total pore surface area of lactose tablets. The changes in tabl et microstructure with increasing compression force were particularly well detected from the pore volume size distributions of tablets. Comp ression speed affected the total pore volume of lactose tablets, both mean and median pore diameters of lactose tablets and mannitol tablets compressed from granules produced with a low amount of liquid, and th e median pore diameter of glucose tablets. The compression speed depen dence of these parameters was a sign of the time-dependent deformation of materials during compression. The amount of granulation liquid aff ected the total pore surface area of lactose and mannitol tablets. Wit h a high amount of liquid, the surface area of pores was greater. The mean pore size of all tablets and the median pore diameter of mannitol tablets were smaller when a high amount of granulation liquid was use d. Even when compressed with a high force, the pore volume size distri butions of mannitol tablets with a low amount of granulation liquid we re broader and the maxima were at larger pore diameters. It was conclu ded that each porosity parameter measured characterised the pore struc ture of compressed tablets from a different aspect. Thus, the use of a ll porosity parameters proved to be useful.