A study on the impact of HPMC viscosity grade and proportion on the functional properties of co-freeze-dried mannitol-HPMC cushioning excipients for compacted MUPS

Impact of HPMC viscosity grade and proportion on the functional properties of co-freeze-dried mannitol-HPMC cushioning excipients for compacted MUPS

The co-processing of multiple excipients is driven by the potential of diversifying the properties and functionality of excipients when they are combined. Bulk freeze-drying-milling is a novel secondary processing approach to develop co-processed excipients. It offers a significant advantage of formulation flexibility.

This study was designed to systematically investigate the impact of 3 factors, hydroxylpropyl methyl cellulose (HPMC) viscosity grade, mannitol to HPMC ratio and particle size fraction on the functional properties of freeze-dried (FD) mannitol-HPMC cushioning excipients produced for multi-unit pellet system tableting. Based on the results, the investigated formulation variables were significant in determining the functional properties of the FD-mannitol-HPMC cushioning excipients.

Among the formulations, FD-mannitol-HPMC F4M (3:1 ratio) excipients exhibited the best cushioning performance. It was postulated that the protective effects of the cushioning excipient were brought about by its propensity for rearrangement around the coated pellets to reduce detrimental pellet-pellet contact and ability to absorb damaging compressive forces. Conversely, FD-mannitol-HPMC vLV (3:1 ratio) had cushioning effects but showed short disintegration time while maintaining adequate tablet tensile strength. Overall, the results of this study highlighted the impact of formulation variables on the functional properties of the cushioning excipients, arising from an interplay of the freeze-dried particle properties.