We present a systematic and automatic approach for integrating tableting reduced-order models with upstream unit operations. The approach not only identifies the upstream critical material attributes and process parameters that describe the coupling to the first order and, possibly, the second order, but it also selects the mathematical form of such coupling and estimates its parameters. Specifically, we propose that the coupling can be generally described by normalized bivariate rational functions. We demonstrate this approach for dry granulation, a unit operation commonly used to enhance the flowability of pharmaceutical powders by increasing granule size distribution, which, inevitably, negatively impacts tabletability by reducing the particle porosity and imparting plastic work. Granules of different densities and size distributions are made with a 10% w/w acetaminophen and 90% w/w microcrystalline cellulose formulation, and tablets with a wide range of relative densities are fabricated. This approach is based on product and process understanding, and, in turn, it is not only essential to enabling the end-to-end integration, control, and optimization of dry granulation and tableting processes, but it also offers insight into the granule properties that have a dominant effect on each of the four stages of powder compaction, namely die filling, compaction, unloading, and ejection.
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Tabletability Flip in Dry Granulated Systems
Abstract PurposesThe tabletability flip phenomenon (TFP), where an active pharmaceutical ingredient (API) with poorer tabletability exhibits better tabletability when formulated with excipients, has been well documented in direct compression systems. However, the impact of granulation on TFP remains unexplored. Hence, the purpose of this work was to investigate the occurrence and underlying mechanisms of TFP in dry-granulated formulations. MethodsAcetaminophen (APAP) and ibuprofen (IBU) were used as model APIs since they exhibit TFP in non-granulated blends. Granules of each API were prepared at two porosity levels (9% and 19%) by controlling compaction pressure. Granules with and without varying levels of extragranular magnesium stearate (MgSt) were evaluated for tabletability, bonding area (BA), and bonding strength (BS). ResultsFor the more porous granules (19% porosity), extensive fragmentation during compaction preserved TFP through the same mechanism observed in the pre-blends. In contrast, the less porous granules (9% porosity) remained largely unfragmented during compaction, allowing their intrinsic mechanical properties to govern the BA–BS interplay. Although APAP granules showed smaller BA due to lower deformability, the higher BS led to superior tabletability, thus maintaining TFP. The incorporation of ≥ 1% MgSt minimized BS difference between formulations, effectively eliminating TFP, since the softer IBU granules exhibited higher tabletability due to larger BA. ConclusionThese results demonstrated the applicability of the BA–BS framework in explaining TFP in granulated systems and highlight the importance of controlling granule porosity and MgSt levels to optimize tabletability in dry granulation processes.
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- Award ID(s):
- 2137264
- PAR ID:
- 10671509
- Publisher / Repository:
- Springer Nature
- Date Published:
- Journal Name:
- Pharmaceutical Research
- ISSN:
- 0724-8741
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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