STABLE POLYMORPH OF R-MDMA HCL

1 - 23 . (canceled)

24 . A pharmaceutical composition comprising crystalline (R)-3,4-methylenedioxymethamphetamine ((R)-MDMA) HCl characterized by X-ray Powder Diffraction (XRPD) peaks at 7.9±0.2, 14.0±0.2, and 15.8±0.2° 2θ.

25 . The pharmaceutical composition of claim 24 , wherein the crystalline (R)-MDMA HCl is characterized by an XPRD pattern substantially similar to 204 in FIG. 2 A .

26 . The pharmaceutical composition of claim 24 , wherein the crystalline (R)-MDMA HCl is further characterized by XRPD peaks at 17.5±0.2, 24.8±0.2, and 15.8±0.2° 2θ.

27 . The pharmaceutical composition of claim 24 , wherein the crystalline (R)-MDMA HCl is further characterized by XRPD peaks at 17.5±0.2, 24.8±0.2, 20.5±0.2, 26.7±0.2, 29.0±0.2, and 37.9±0.2° 2θ.

28 . The pharmaceutical composition of claim 24 , wherein the crystalline (R)-MDMA HCl exhibits a monoclinic crystal system with cell parameters of a=7.17±0.05 Å, b=7.61±0.05 Å, c=11.75±0.05 Å, α=90±1°, β=107±1°, γ=90±1°, V=612±5 Å 3 /cell.

29 . The pharmaceutical composition of claim 24 , wherein the crystalline (R)-MDMA HCl exhibits a solubility of >110 mg/mL in water.

30 . The pharmaceutical composition of claim 24 , wherein the crystalline (R)-MDMA HCl exhibits a Differential Scanning calorimetry (DSC) thermogram comprising an endotherm peak with an onset at 185° C.

31 . The pharmaceutical composition of claim 24 , wherein the crystalline (R)-MDMA HCl exhibits a DSC thermogram comprising an endothermic peak at 186° C.

32 . The pharmaceutical composition of claim 24 , wherein the crystalline (R)-MDMA HCl exhibits 0.2±0.1% weight loss between 52-231° C. as measured by thermogravimetric (TGA) analysis.

33 . The pharmaceutical composition of claim 24 , wherein the crystalline (R)-MDMA HCl exhibits 5.28±0.02% weight gain from 5-95% relative humidity (RH) and a 5.35±0.02% weight loss from 95-5% RH at 10% RH increments under a nitrogen purge as measured by Dynamic Vapor Sorption (DVS).

34 . The pharmaceutical composition of claim 24 , wherein the crystalline (R)-MDMA HCl exhibits physical stability upon storage at 97% RH for 6 days.

35 . The pharmaceutical composition of claim 24 , wherein the pharmaceutical composition is an oral dosage form.

36 . The pharmaceutical composition of claim 24 , where the pharmaceutical composition further comprises a pharmaceutically acceptable excipient.

37 . The pharmaceutical composition of claim 24 , wherein the enantiomeric excess of (R)-MDMA in the pharmaceutical composition is least about 95%.

38 . The pharmaceutical composition of claim 24 , wherein the enantiomeric excess of (R)-MDMA in the pharmaceutical composition is least about 98%.