(631j) Study Effect of Hydroxypropyl Cellulose Grade and Foam Quality On Foam Granulation of a High Drug Load Formulation

Purpose: To investigate the influences of HPC grade and foam quality on foam granulation of a high drug load formulation.

Methods: Two grades of HPC (LF and EXF) with different viscosities were used to produce foam of varied quality (90%, 50%, and 0%). The foam quality is expressed as the ratio of the air to the liquid on volume basis. A pilot scale foam generator was employed to make foam of desired quality. The viscosities of the HPC solutions were determined using Brookfield^Ò viscometer. A high drug load (80.5% w/w) formulation was granulated in a Diosna^Ò granulator fitted with 4L bowl (batch size: 400 g, HPC solution delivered as foam: 25% w/w, foam addition rate: 75 g/min, impeller tip speed: 5.6 m/s, high chopper, 95 s granulation time, 30 s wet massing time). The power profiles were monitored during granulation. The granules were dried using a fluid bed dryer at 75°C and further milled by passing through a conical mill fitted with 0.045 inch round screen. Granule properties such as particle size, flow and bulk density were measured. The compactibility of the granules was assessed using Stylcam^Ò.

 

Results: The viscosities of HPC LF and EXF solutions used to prepare the foam were 282 and 141 cP. At similar foam qualities, HPC LF foam resulted in higher power consumption than HPC EXF foam. There was no clear trend on power consumption with decreasing foam quality during granulation. Granulations made with different HPC grade and foam quality did not exhibit any significant difference in drying behavior. The granulation prepared with HPC EXF 0% foam quality exhibited the highest % fines among all the granulations. Granulations prepared with 50% foam quality showed poorer flow compared to 90% and 0% foam quality, regardless of HPC grade. Bulk density was similar among the granulations. Compactibility of the granulations was similar, although there were some difference when dwell time was decreased.  

 

Conclusions: HPC grade or the foam quality did not have major effect during the foam granulation process and on the granulation properties when granulated at optimal foam level of 25% w/w. However, HPC grade and foam quality can be chosen to tailor the desired granulation properties.