Ann-Sofie Persson^a and Göran Alderborna^a
Department of Pharmaceutical Biosciences, Uppsala University, Box 591, SE-751 24 Uppsala, Sweden

Purpose. To study the applicability of coupling a three-stage tableting model [1], i.e. the relationship between tablet tensile strength and compaction pressure, to a compression profile in order to predict both tabletability and compactibility of α-lactose monohydrate powders ranging in particle size from ~3.5-203 µm.

Methods. Tabletability relationships were predicted based on the Kawakita 𝑏−1 and the Heckel parameters in combination with a reference tablet tensile strength value, all parameters derived from a single compression experiment. Compactibility relationships were predicted based on in-die porosity data corrected for viscoelastic recovery and coupled to the predicted tablet tensile strength values.

Results. The experimental tabletability relationships followed in general the three-stage model well and the predicted tabletability relationship using this model resulted in a good resemblance to the experimental data with regard to both slope and plateau values (Fig. 1a). The compactibility was described with the Ryshkewitch-Duckworth equation. At high porosities the experimental profiles deviated from linearity and for some powders a plateau was evident at low porosities. The predicted compactibility profiles followed the experimental profiles well (Fig. 1b) and the predicted curves captured the curved regions at high porosities. Moreover, the predicted and experimental extrapolated tablet tensile strength corresponded well.

Conclusions. The hybrid approach using the three-stage tableting model could be used to predict tabletability and compactibility relationships. Thus, the approach can be used to assess comprehensive information about the tablet forming ability of a powder without the need of a large number of experiments.

References:

[1] Alderborn, G., A novel approach to derive a compression parameter indicating effective particledeformability, Pharm. Dev. Technol., 2003, 8 (4), 367-377