| 摘要 |
Crystalline NG-monomethyl-L-arginine hydrochloride is disclosed. At least three distinguishable isomorphic forms are present. The solid salt can be made by dissolving NG-monomethyl-L-arginine in hydrochloric acid and crystallising out NG-monomethyl-L-arginine hydrochloride. The crystallising step requires several months at low temperature. However, the process can be facilitated by seeding with crystals of NG-monomethyl-L-arginine hydrochloride. Alternatively, crystalline NG-monomethyl-L-arginine hydrochloride can be prepared by dissolving a salt of NG-monomethyl-L-arginine other than the hydrochloride salt with hydrochloric acid and removing the original salt forming ion by crystallising out the hydrochloride salt.
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