Investigation on bonding and disintegration properties of pharmaceutical materials

Abstract The disintegration properties of differing pharmaceutical materials having well-known bonding mechanisms were investigated in various media. The materials were sodium chloride, lactose monohydrate and microcrystalline cellulose. They bind mainly with intermolecular bonds and are therefore supposed to loose bonding strength in media with a suitable dielectric constant. The media used were water, methanol and isopropanol. The tablets were prepared under controlled conditions and checked for disintegration time, liquid penetration and disintegration force development. Whenever disintegration did not occur, the crushing strength after soaking in the various media was measured. For microcrystalline cellulose, the swelling properties of the powder material were also measured. The results obtained show that the annihilation/weakening of intermolecular bonds, which are due to the environmental changes in dielectric constant, may play a role in the disintegration of tablets. However, it has to be taken in consideration that the medium must be capable of penetrating into the tablet, that the extent of bond weakening depends on the dielectric constant of the media and that the mechanical stress is likely to be decisive in provoking tablet disintegration. The type of disintegration that is caused by the annihilation/weakening of intermolecular bonds is not accompanied by any force development, therefore it may be referred to as a passive mechanism of disintegration. Whenever disintegration is accompanied by force development, this may be referred to as an active mechanism of disintegration. Swelling is always present in this mechanism .