Towards an accurate and precise determination of the solid–solid transition temperature of enantiotropic systems

Ternary and quaternary phase diagrams: key tools for chiral resolution through solution cocrystallization

“…All vials were hermetically sealed and heated up to 60 uC until complete dissolution. They were stored at constant temperature and seeded with all of the solid forms possibly occurring in the corresponding ternary phase diagram (for each diagram the appropriate selection was made from RS-1 form I, [34][35][36][37] S-1, S-2, and S-1:S-2 cocrystal). After two weeks, the system was assumed to have reached equilibrium.…”

Assessment of Recent Process Analytical Technology (PAT) Trends: A Multiauthor Review

“…During cooling, form II spontaneously nucleates. As this form nucleates above the transition temperature of 30.5 °C, this nucleation process is opposite to Ostwald’s rule of thumb. Further cooling is characterized by secondary nucleation and crystal growth of this form.…”

Detection of the II–I Etiracetam solvent-mediated polymorphic transformation through the online monitoring of the suspension apparent viscosity

“…Etiracetam can crystallize in two distinct crystallographic forms, hereafter referred as to form I and II, which are enantiotropically related. The solid-solid transition temperature delimiting the temperature ranges of stability of these two forms is equal to 30.5 1C: form I is the stable crystallographic form below 30.5 1C while form II is the stable crystallographic form beyond 30.5 1C [18]. The solubilities of the two forms of Etiracetam in methanol have been experimentally determined by the combination of five different experimental techniques [19].…”