Roll Compaction and Tableting of High Loaded Metformin Formulations Using Efficient Binders
Metformin has a poor tabletability and flowability. Therefore, metformin is typically wet granulated with a binder before tableting. To save production costs, it would be desirable to implement a roll compaction/dry granulation (RCDG) process for metformin instead of using wet granulation. In order to implement RCDG, the efficiency of dry binders is crucial to ensure a high drug load and suitable properties of dry granules and tablets. This study evaluates dry granules manufactured by RCDG and subsequently tableting of high metformin content formulations (≥ 87.5%). Based on previous results, fine particle grades of hydroxypropylcellulose and copovidone in different fractions were compared as dry binders. The formulations are suitable for RCDG and tableting. Furthermore, results can be connected to in-die and out-of-die compressibility analysis. The addition of 7% of dry binder is a good compromise to generate sufficient mechanical properties on the one hand, but also to save resources and ensure a high metformin content on the other hand. Hydroxypropylcellulose was more efficient in terms of granule size, tensile strength and friability. Three percent croscarmellose was added to reach the specifications of the US Pharmacopeia regarding dissolution. The final formulation has a metformin content of 87.5%. A loss in tabletability does not occur for granules compressed at different specific compaction forces, which displays a robust tensile strength of tablets independent of the granulation process.