Influence of the porosity of cushioning excipients on the compaction of coated multi-particulates
July 1, 2020, midnight
Ramy N. Elsergany
Lai Wah Chan
Paul Wan Sia Heng
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Compacting tablets in a multiple unit-pellet system (MUPS) presents significant challenges due to potential damage to the functional polymer coat and the risk of pellet segregation during the tableting process. This study aims to explore the impact of porous pellets as cushioning agents, mitigating issues related to segregation during tableting. Various drying techniques were employed to produce microcrystalline cellulose (MCC) pellets with different porosities. Sodium chloride was incorporated into the pellet formulation as a pore-forming agent to create a porous skeleton post-production through aqueous extraction. The pellets were characterized for porosity, crushing strength, and yield pressure. Tablets were then prepared using unlubricated pellets, and their tensile strengths were determined. Blends containing polymer-coated pellets and cushioning pellets with varying porosities were compacted at different pressures.
The study revealed that pellet porosity was highest with freeze drying, followed by fluid bed drying, and least porous with oven drying. There existed an inverse relationship between pellet porosity and strength. The protective effect of cushioning pellets relied on their porosity, with pellets manufactured by leaching NaCl from MCC-NaCl (1:1) showing significantly higher porosities compared to MCC PH101 only pellets. Interestingly, the balance between porosity and bulk density was crucial for effective cushioning, as evidenced by MCC PH101-NaCl (1:3) pellets having higher porosity but exhibiting less cushioning effect than MCC PH101-NaCl (1:1). The study concluded that achieving a suitable balance between porosity and bulk density in cushioning pellets was essential for effective protection during compaction. Furthermore, MUPS tablets prepared with porous freeze-dried MCC PH101 (NaCl fraction leached) pellets demonstrated improved drug content uniformity and mechanical strength compared to tablets prepared with unprocessed MCC PH105.