High-Molecular-Weight Hypromellose from Three Different Suppliers: Effects of Compression Speed, Tableting Equipment, and Moisture on the Compaction

Use of higher tableting speeds is gaining increasing importance for pharmaceutical industry. There is a profound lack of new studies of mechanical properties of hypromellose, and none of them evaluate different suppliers. Thus, the objective of this study was to investigate flow and compaction properties of different grades of hypromellose (type 2208) from three different suppliers, with particular focus on the effect of the compression speed. The flow properties were determined using flow time, shear cell, Carr index, and constant B from initial part of Heckel profile. Compaction properties were quantified using "out-of-die" Heckel, Walker, and Kuentz-Leuenberger models; two tensile strength profiles (tabletability and compactibility); and elastic recovery. Compaction was performed by both an instrumented single-punch press and a high-speed rotary press simulator. Due to larger, rounder, and smoother particles, both Methocel™ DC grades together with Benecel™ K4M showed better flow properties compared with other materials, with Metolose® K100M having the worst flow. Overall, Benecel™ K100M and Metolose® K100M showed the best compaction properties, closely followed by Metolose® K4M. Heckel analysis showed the highest compressibility of Benecel™ K100M, followed by both Methocel™ DC grades. Kuentz-Leuenberger model showed to have no practical superiority in comparison with Heckel model in the compression pressure range used. Results of strain rate sensitivity showed that Methocel™ K4M DC was the least susceptible to change of tableting speed, followed by Methocel™ K100M DC and both grades of Benecel™, and in contrast, both grades of Metolose® were the most sensitive. Effect of moisture on compaction was also studied.

High-shear granulation of high-molecular weight hypromellose: effects of scale-up and process parameters on flow and compaction properties

CONTEXT

Knowledge of the effects of high-shear granulation process parameters and scale-up on the properties of the produced granules is essential for formulators who face challenges regarding poor flow and compaction during development of modified release tablets based on high-molecular weight hypromellose (hydroxypropylmethylcellulose (HPMC)) polymers. Almost none of the existing studies deal with realistic industrial formulation.

OBJECTIVE

The aim was to investigate the effects of scale-up and critical process parameters (CPPs) of high-shear granulation on the quality attributes of the granules, particularly in terms of the flow and compaction, using a realistic industrial formulation based on HPMC K100M polymer.

METHODS

The flow properties were determined using flow time, Carr index, tablet mass, and crushing strength variations. The compaction properties were quantified using the 'out-of-die' Heckel and modified Walker models, as well as the tensile strength profile and elastic recovery. High-shear granulation was performed at different scales: 4 L, 300 L, and 600 L.

RESULTS AND CONCLUSION

The scale itself had larger effects on the granule properties than the CPPs, which demonstrated high robustness of formulation on the individual scale level. Nevertheless, to achieve the desired flow and compaction, the values of the CPPs need to be precisely selected to fine-tune the process conditions. The best flow was achieved at high volumes of water addition, where larger and more spherical granules were obtained. The CPPs showed negligible influence on the compaction with no practical implications, however, the volume of water addition volume was identified as having the largest effects on compaction.