Two ortho­rhom­bic polymorphs of hydro­morphone

Conditions to obtain two polymorphic forms by crystallization from solution were determined for the analgesic drug hydro­morphone [C(17)H(19)NO(3); systematic name: (4R,4aR,7aR,12bS)-9-hy­droxy-3-methyl-1,2,4,4a,5,6,7a,13-octa­hydro-4,12-methano­benzofuro[3,2-e]iso­quinolin-7-one]. These two crystalline forms, designated as I and II, belong to the P2(1)2(1)2(1) ortho­rhom­bic space group. In both polymorphs, the hydro­morphone mol­ecules adopt very similar conformations with some small differences observed only in the N-methyl amine part of the mol­ecule. The crystal structures of both polymorphs feature chains of mol­ecules connected by hydrogen bonds; however, in form I this inter­action occurs between the hydroxyl group and the tertiary amine N atom whereas in form II the hydroxyl group acts as a donor of a hydrogen bond to the O atom from the cyclic ether part.