The effect of spray drying on the compaction properties of hypromellose acetate succinate

The aim of this study was to evaluate the compaction behavior of a model two-component amorphous spray-dried dispersion system compared with the unprocessed excipients, using simulated rotary tablet press production conditions.

In this study, the stabilizing polymer, hypromellose acetate succinate (HPMCAS), was solubilized and spray dried with and without sodium lauryl sulfate (SLS). The impact of compression force and speed on the tabletting process was quantified by means of tablet tensile strength, compaction energy, and Heckel analysis.

Addition of the surfactant SLS, spray dried or as a physical mix, reduced the tablet strength. However, a lesser impact on the unprocessed excipients was observed in comparison with the spray-dried excipients. In the presence of 1% (w/w) SLS, tablets displayed a tendency to cap when compressed at higher speeds, supported by high elastic energy values indicating high uniaxial stress upon decompression. In the presence of 3% (w/w) SLS, tablets could not be produced at high speeds. Heckel analysis revealed a greater strain rate sensitivity of HPMCAS when spray dried in the presence of surfactant. Exposure of samples to a range of relative humidities before compaction had no effect on tablet strength.

This study has shown that spray drying of HPMCAS in the presence of a surfactant affects the compressibility of the material, resulting in decreased tablet strength, increased elastic deformation, and capping.