In this article, we investigated aripiprazole + Kollidon VA64 (ARP/KVA) and aripiprazole + Soluplus (ARP/SOP) amorphous solid dispersions. Thermal properties of all prepared systems have been examined by means of differential scanning calorimetry (DSC). Compositions revealing the recrystallization tendency were subsequently investigated by means of broadband dielectric spectroscopy (BDS). On the basis of dielectric data, the physically stable drug-polymer concentrations have been found. Finally, these systems have been investigated by rheology, which enables us to determine the minimal temperature required for dissolving the drug in the polymeric matrix, as well as the temperature dependence of the sample viscosity. Our investigations have shown that the amorphous form of the investigated antipsychotic drug might be effectively stabilized by both employed polymers. However, due to the better stabilization effect and the more favorable rheological properties, KVA proved to be a better polymeric excipient for extrusion of amorphous aripiprazole.
Keywords: BDS; amorphous aripiprazole; amorphous pharmaceuticals; amorphous solid dispersions; dielectric spectroscopy; hot melt extrusion; improvement stability; physical stability; rheological properties; rheology.