Spontaneous foaming during vacuum drying of polyvinylpyrrolidone- and sugar-alcohol mixtures and enhancement of water-dissolution of water insoluble drug

We experimentally investigate the foamability of PVP 2.5k/ethanol and amorphous α-maltose/methanol solution under moderate vacuum. We investigate the influence of the solution concentration and the impact of the container shape on the foamability. We show that spontaneous foaming is strongly influenced by the container’s shape. The concentration of the solution is another important parameter, and our results suggest that, for a given solution, there seems to be only a narrow concentration window that enables the formation of a stable foam. When loaded with a model hydrophobic drug (ibuprofen), the spontaneous foaming enhances the dispersion of the drug molecules, by acting as an additional mixing force through extensive shear of the solution.