Influence of tableting on the enzymatic activity of different alpha-amylases using various excipients

The purpose of the study was to show the influence of compression pressure on the enzymatic activity of different types of alpha-amylases and to analyze the loss of activity of alpha-amylase in mixtures with different excipients. Following that, the properties of excipients used for tableting enzymes were evaluated. Tablets were produced on an instrumented single punch tableting machine. The pure amylases were tableted with increasing graded compaction pressures. Mixtures were tableted to different maximum relative densities, rho(rel,max). The remaining enzymatic activity of the alpha-amylase in the tablets was determined by the starch iodine reaction. The results show a difference between different types of alpha-amylase depending on their origin and additives. Enzymatic inactivation occurs for the pure materials at all pressures used. It is initiated during and continues after compaction. It can be inhibited by freezing the tablets. Another possibility is to tablet the enzyme in a mixture with excipients, which prevent inactivation by softly embedding the enzyme. One example which even stabilizes alpha-amylase at high volume reduction is kappa-carrageenan. In conclusion, enzymatic inactivation can be markedly reduced when excipients are used for tableting, which require little compaction pressure and are able to release the mechanical stress in the form of expansion.