Adriforant tartrate hydrate, also known as ZPL-3893787 tartrate hydrate, PF-3893787 tartrate hydrate and ZPL-389 tartrate hydrate, is a novel histamine H4 receptor antagonist. Adriforant tartrate hydrate shows an excellent in vitro profile that warrants their further investigation in relevant models of human disease. Histamine H4 receptor (H4R) has become a promising target for immuno-inflammatory diseases, such as allergic rhinitis, asthma or dermal allergies.