Preparation and Properties of Citric and Tartaric Acid Salts of Piperazine

The following salts of piperazine with tartaric and citric acids were prepared: piperazine monotartrate, piperazine ditartrate, piperazine monocitrate, piperazine dicitrate, and tripiperazine dicitrate. There are indications that dipiperazine monotartrate and tripiperazine monocitrate exist in solution, but attempts to isolate these salts were not successful. The tartaric and citric acid salts of piperazine are odorless white crystalline solids with relatively high water solubility. The tartrate salts are nonhygroscopic whereas the citrate salts occur as a variety of hydrates, some of which are quite stable. All the salts are relatively stable at elevated temperatures and are suitable for incorporation in common pharmaceutical forms; however, there are characteristic differences which should be considered in their use.