Structure of 3-{2-[4-(6-fluoro-1,2-benzisoxazol-3-yl)piperidino]ethyl}-6,7,8,9-tetrahydro-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one (risperidone)

Thermodynamics of risperidone and solubility in pure organic solvents

“…In all solutions, the solid material was verified to be form I. All experimental peaks match those in the theoretical pattern generated from the known structure of risperidone form I [2] (refcode WASTEP). The theoretical pattern of form II [3] (refcode WASTEP01) contains a dominant peak at 21.78 ° and a distinctive region around 17-18 ° distinguishing it from form I, both of which are completely absent from all XRPD patterns collected.…”

“…1. There are two reported polymorphs with crystal structures available in the Cambridge Structural Database (CSD) [2,3]. However, very limited data is available on the solid-liquid solubility of risperidone.…”

Risperidone chloride 2.5-hydrate: a new crystalline form

“…For this reason, well documented characteristics of its crystalline form are required. To date, four solid forms of risperidone have been reported (Krochmal et al, 2004;Reddy et al, 2004) and characterized by X-ray powder diffraction patterns, but only one of their crystal structures has been determined (Peeters et al, 1993). In the course of our studies, we report here the crystal structure of a new 2.5-hydrate, (I).…”

Paliperidone: 3-{2-[4-(6-fluoro-1,2-benzoxazol-3-yl)piperidin-1-yl]ethyl}-9-hydroxy-2-methyl-1,6,7,8,9,9a-hexahydropyrido[1,2-a]pyrimidin-4-one

“…For pharmacological background, see: de Leon et al (2010); Spina & Crupi (2011). For related structures, see: Peeters et al (1993); Ravikumar et al (2005); Sun & Zhang (2009); Wang & Pan (2006). For graph-set analysis of hydrogen bonds, see: Etter et al (1990); Bernstein et al (1995).…”

“…It is a benzisoxazole derivative and the major active metabolite of risperidone, a widely used atypical antipsychotic approved for the treatment of schizophrenia and other psychiatric disorders. The pharmacokinetics of paliperidone versus risperidone have been published (de Leon et al, 2010) (Peeters et al, 1993), risperidone N-oxide hydrogen peroxide methanol solvate (Ravikumar et al, 2005), risperidone chloride 2.5 hydrate (Wang & Pan, 2006) (Sun & Zhang, 2009) have been reported. In view of the importance of the title compound we herein report its molecular and crystal structure.…”