Compaction behavior of galenIQ 801 after roller compaction

Isomalt is frequently used in pharmaceutical formulations. This study is conducted to characterize the properties of galenIQ 801, a recently marketed isomalt grade, after roll compaction. Pure isomalt and a mixture of equal parts of isomalt and dibasic calciumphosphate are tested likewise. Different specific compactions forces from 2 to 14 kN/cm are used for roll compaction and the resulting granules are compressed to tablets with tableting forces from 3 to 15 kN. The granules are characterized in terms of flowability and particles size, whereas the tensile strength, porosity, disintegration time, and friability are used to define the tablets. FFC-values over 10 indicate excellent flowability for the granules prepared with specific compaction forces of 6 kN/cm and more for pure isomalt and at 10 kN/cm for the blend. This can be explained with the increasing particle size after roll compaction as the x50-values grow from around 10 µm to at least 440 µm. The tensile strength is calculated to evaluate the impact of roll compaction on the compactibility of the granules. The tensile strength of pure isomalt is higher compared to the mixture. At the highest tableting force, pure isomalt tablets display maximum tensile strengths of 1.4 MPa at specific compaction forces of 2 kN/cm and 6 kN/cm, which decrease to 1 MPa and even lower at higher specific compaction forces. In case of the mixture, the tensile strength at 15 kN tableting force is approximately 0.8 MPa for all specific compaction forces. With increasing tableting force, the porosity decreases from over 25 % to around 16 %, whereas the disintegration time increases. The friability test was only passed by some of the pure isomalt tablets (specific compaction force < 14 kN/cm and tableting force > 9 kN), none of the tablets prepared from the blend fulfilled the requirements. In conclusion, it can be stated, that galenIQ 801 is suitable for recompression after roller compaction. Regarding tensile strength, flowability, and friability, a specific compaction force of 6 kN/cm is most adequate.