Solid-state characterization of an NR2B selective N-methyl d-aspartate (NMDA) antagonist polymorphs.

(-)-6-[2-[4-(3-Fluorophenyl)-4-hydroxy-piperidin-1-yl]-1-hydroxyethyl]-3,4-dihydro-quinolin-2(1H)-one (compound A) is an NR2B selective N-methyl d-aspartate (NMDA) antagonist that has shown at least two polymorphs, forms I and II. In this report, we prepared two polymorphs, forms I and II and their crystal forms were identified and characterized by single crystal X-ray diffractometry, differential scanning calorimetry (DSC) and variable temperature powder X-ray diffractometry (VT-PXRD). The results of DSC and VT-PXRD suggested that compound A has at least three polymorphic forms: I, II and a new form III, and that forms II and III showed an enantiotropic relationship.

Solid form selection of zwitterionic 5-HT4 receptor agonist.

From discovery synthesis of a zwitterionic pharmaceutical compound, 4-{[4-({[(3-isopropyl-2-oxo-2,3-dihydro-1H-benzimidazol-1-yl)carbonyl]amino}methyl)piperidin-1-yl]methyl}tetrahydro-2H-pyran-4-carboxylic acid (compound A), two anhydrous ZW-I and ZW-II and two hydrate forms ZW-III and ZW-IV were identified. Although stable form ZW-I was chemically stable at 70 degrees C/75% RH for 10 days, it was transformed to hydrate form ZW-IV under ambient conditions within a few days, taking up water from atmospheric moisture. In order to select a solid form for further investigation, solid-state characterization, salt screening on 96-well plate, stable polymorph and hydrate screening and physical stability were performed.