Comparison of HPMCAS Chemical Grades (L, M, and H) for Amorphous Solid Dispersion by Hot-Melt Extrusion. I: Rheology and Extrudability with Itraconazole as a Model Drug

Hydroxypropyl methylcellulose acetate succinate (HPMCAS) is widely used as a polymeric carrier for preparing amorphous solid dispersions (ASDs) of poorly water-soluble drugs due to its ability to maintain drug supersaturation in aqueous media. However, most marketed ASDs with HPMCAS are prepared by spray drying. Hot melt extrusion (HME), an environmentally friendly, solvent-free, and continuous process for preparing ASDs, is rarely used for HPMCAS because it requires processing temperatures of at least 170°C, which can degrade the polymer, the drug, or both. HPMCAS is available in three chemical grades (L, M, and H), but there is no comparative evaluation of their suitability for HME.