Structural multiplicity in a solvated hydrate of the anti-retroviral protease inhibitor Lopinavir.

Lopinavir is a potent protease inhibitor that is used as a first-line pharmaceutical drug for the treatment of HIV. The multi-component solvated Lopinavir crystal, systematic name (2S)-N-[(2S,4S,5S)-5-[2-(2,6-di-methyl-phen-oxy)acetamido]-4-hy-droxy-1,6-di-phenyl-hexan-2-yl]-3-methyl-2-(2-oxo-1,3-diazinan-1-yl)butanamide-ethane-1,2-diol-water (8/3/7) 8C(37)H(48)N(4)O(5)·3C(2)H(6)O(2)·7H(2)O, was prepared using evaporative methods. The crystalline material obtained from this experimental synthesis was characterized and elucidated by single-crystal X-ray diffraction (SC-XRD). The crystal structure is unusual in that the unit cell contains 18 mol-ecules. The stoichiometric ratio of this crystal is eight Lopinavir mol-ecules [8(C(37)H(48)N(4)O(5))], three ethane-1,2-diol mol-ecules [3(C(2)H(6)O(2))] and seven water mol-ecules [7(H(2)O)]. The crystal packing features both bi- and trifurcated hydrogen bonds between atoms.