The role of fluids in high-pressure polymorphism of drugs: different behaviour of beta-chlorpropamide in different inert gas and liquid media

The hydrostatic compression of beta-chlorpropamide gives different high-pressure phases, depending on the choice of pressure-transmitting fluid (paraffin, neon and helium). This is particularly surprising as none of these fluids interact obviously with the solid at ambient pressure. This phenomenon is not related to dissolution and recrystallization, in contrast to what has been previously observed for b-chlorpropamide in a 1 : 1 pentane-isopentane mixture.