This technology includes two new salt forms for (2R,6R)-hydroxynorketamine (2R,6R-HNK), which is the lead molecule being developed for treatment-resistant depression. Currently, 2R,6R-HNK is being developed as the HCl salt. The HCl salt is slightly hygroscopic at high RH. This is a potential liability, especially in an oral pill form. Recently the malonate and salicylate salt have been discovered and found to have excellent crystalline behavior while also not having the hygroscopic liability the HCl salt holds. This represents a clear advantage.
This can form the basis of a solid oral formulation for 2R,6R-HNK, as the malonate or salicylate salt.
Two new salt forms have been discovered which have good crystallinity and do not have the hygrocopicity that the HCl salt possesses.