| Popis: |
In this study the relationship between the dissolution properties of different types of crystalline lactose and the disintegration of tablets, containing these lactoses, was investigated. Tablets, compressed from either α-lactose monohydrate or crystallized β-lactose disintegrated very quickly in water, as a result of rapid liquid uptake and fast dissolution of the bonds. Tablets compressed from anhydrous α-lactose did not disintegrate at all when brought into contact with water, but dissolved during the disintegration procedure. This effect, which was shown to be caused by poor water penetration into the tablets, is attributed to a combination of both small pore diameters and precipitation in the pores of dissolved anhydrous α-lactose as α-lactose monohydrate, in the course of the penetration process. This precipitation is an effect of the smaller initial solubility of α-lactose monohydrate compared with that of anhydrous α-lactose. The same phenomenon could be seen for tablets containing roller-dried β-lactose when they were compressed at high forces. In this case the poor disintegration of the tablets is attributed to the combination of the presence of about 20% anhydrous α-lactose in roller-dried β-lactose and the small pore diameters in the tablets. |
