Powder flowability as a functionality parameter of the excipient GalenIQ 720

Objective: The purpose of the work was the assessment of the GalenIQ 720 flowability as a functionality parameter of the excipient, comparing two different methods.

Methods: The evaluated parameters were the powder flow through different size orifices and the compressibility index, as absolute values and as values relative to Helmcel 200. The parameters determined with pure excipients and in mixtures with a model drug, metronidazole.

Results: The compressibility index is a specific measurement for each powders blend that allows the assessment of its overall flow properties. Flowability, expressed as the flow rate, shows so many different results as orifices are being tested. Both methods exhibit comparable results only by wide orifice sizes where the interaction with de orifice walls is minimized. The flow rate increases progressively, mostly in a potential relationship, with an increasing orifice diameter. The flow rate of GalenIQ 720 attains a maximum with 0.4-0.8% magnesium stearate.

Formulations containing GalenIQ 720 show about 2.8 times greater flowability than those containing Helmcel 200 while the flowability of GalenIQ 720 is about 8.7 times greater than that of Helmcel. The presence of metronidazole attenuates the differences observed by the flowability of pure excipients and its spread.

Conclusion: Both methods consistently show a comparable improvement of metronidazole flowability with GalenIQ 720 and a deterioration of the same with Helmcel 200. The knowledge of the individual materials flowability allows the inference of their effect on the flowability of their mixtures but not the magnitude of this effect.