Drug Nanocrystals: theoretical background of solubility increase and dissolution rate enhancement

The peculiar higher solubility of drug nanocrystals compared to macrocrystals appeals to the pharmaceutical field. Indeed, until now, about 70 % of the potential drug candidates are discarded due to low bioavailability related with poor solubility in water. Since a modern and efficient design strategy for nanocrystal-based delivery systems requires the knowledge of the theoretical relation between nanocrystal size and solubility, the aim of this paper is to build up a physically-oriented thermodynamic model relating to nanocrystal dimensions with their melting temperature, enthalpy, solubility and dissolution rate. In particular, the developed model will be applied to vinpocetine, a poorly soluble drug used in the treatment of various types of cerebrovascular circulatory disorder