Pharmaceutical salt of tetrahydroberberine with sulfamic acid prepared via CAHBs

In order to further explore the role of Charge-assisted hydrogen bonds (CAHBs) recognition in the formation of tetrahydroberberine (THB) pharmaceutical salt/cocrystal, based on the analysis of the molecular interactions in forming unit pharmaceutical salts/cocrystal of THB and sulfophenyl acids, we speculate that hydroxyl group of sulfamic acid (SA) may cocrystallize with N atom on the quinoline ring of THB via CAHBs. Consequently, an unreported pharmaceutical salt (C20H22NO4·NH2SO3, THB-SA) of the THB was designed and synthesized. The THB-SA was characterized by single crystal X-ray diffraction, XRPD and TG methods. As expected, structure analysis of the THB-SA revealed that the THB molecule binds to the SA molecule precisely through CAHBs (N+-H···O−) between the N atom on the quinoline ring and sulfonic acid group of SA in asymmetric unit of THB-SA. This successfully implemented work implies that in the preparation of THB pharmaceutical salts/cocrystals, cocrystal formers (CCFs) that can form CAHBs with THB should be selected, which will provide a facilitate way to prepare THB pharmaceutical salts/cocrystals.