TY - JOUR
T1 - Solution mediated polymorphic transformation
T2 - Form II to lIII piracetam in ethanol
AU - Maher, Anthony
AU - Croker, Denise M.
AU - Rasmuson, Åke C.
AU - Hodnett, Benjamin K.
PY - 2012/12/5
Y1 - 2012/12/5
N2 - The polymorphic transformation of the Piracetam (2-oxo-1-pyrrolidine acetamide) metastable form II to the stable form III has been investigated in ethanol, by ex-situ X-ray diffraction analysis of the solid phase combined with in situ infrared analysis of solution concentrations. The main factors studied were temperature, mass of solids loading, and pretreatment of the loaded solids. At increasing temperature, the solubility ratio decreases and, hence, the transformation driving force decreases. In spite of this, the nucleation induction time of the stable form and the time for completion of the transformation decrease with increasing temperature. The transformation rate is governed by the nucleation and growth of the stable form, with nucleation likely to take place on the faces of the metastable form crystals and the rate increasing with surface area of the metastable form.
AB - The polymorphic transformation of the Piracetam (2-oxo-1-pyrrolidine acetamide) metastable form II to the stable form III has been investigated in ethanol, by ex-situ X-ray diffraction analysis of the solid phase combined with in situ infrared analysis of solution concentrations. The main factors studied were temperature, mass of solids loading, and pretreatment of the loaded solids. At increasing temperature, the solubility ratio decreases and, hence, the transformation driving force decreases. In spite of this, the nucleation induction time of the stable form and the time for completion of the transformation decrease with increasing temperature. The transformation rate is governed by the nucleation and growth of the stable form, with nucleation likely to take place on the faces of the metastable form crystals and the rate increasing with surface area of the metastable form.
UR - http://www.scopus.com/inward/record.url?scp=84870812391&partnerID=8YFLogxK
U2 - 10.1021/cg301290z
DO - 10.1021/cg301290z
M3 - Article
AN - SCOPUS:84870812391
SN - 1528-7483
VL - 12
SP - 6151
EP - 6157
JO - Crystal Growth and Design
JF - Crystal Growth and Design
IS - 12
ER -