A Possible Infinite Number of Components in a Single Crystalline Phase: On the Isomorphism of Brivaracetam–Guest Molecules

This article highlights the unusual behavior of brivaracetam (BRV: an active pharmaceutical ingredient against epilepsy), which leads to a unique phaseranging from clathrate to solvate to cocrystalformed with an impressive number of apolar guest molecules (any linear alkanes to esters of fatty acids/alcohols, or waxes). Moreover, the investigation of binary systems between linear alkanes and BRV displayed the systematic existence of a syntectic invariant (one solid melts into two nonmiscible liquids) for C_nH_2n+2 with n > 7.