Epitaxial 2D nucleation of the stable polymorphic form of the steroid 7alphaMNa on the metastable form: implications for Ostwald's rule of stages

C Stoica; P Verwer; H Meekes; E Vlieg; P J C M van Hoof; F M Kaspersen

doi:10.1016/j.ijpharm.2005.10.041

Epitaxial 2D nucleation of the stable polymorphic form of the steroid 7alphaMNa on the metastable form: implications for Ostwald's rule of stages

Int J Pharm. 2006 Feb 17;309(1-2):16-24. doi: 10.1016/j.ijpharm.2005.10.041. Epub 2005 Dec 27.

Authors

C Stoica¹, P Verwer, H Meekes, E Vlieg, P J C M van Hoof, F M Kaspersen

Affiliation

¹ IMM Department of Solid State Chemistry, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands.

PMID: 16384675
DOI: 10.1016/j.ijpharm.2005.10.041

Abstract

This paper presents in situ observations of the epitaxial nucleation and growth of the stable polymorph of a steroid, 7alphaMna, on a specific face of the metastable form at low supersaturation, using optical microscopy and in situ Raman spectroscopy. The presence of the metastable polymorph is essential for the nucleation and growth of the stable one. The order of the metastable zones of the stable and metastable polymorphs is reversed for the epitaxial growth process as compared to the case of 3D nucleation. The rate of transformation of the metastable polymorph to the stable one can be controlled by the supersaturation.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Acetone / chemistry
Crystallization
Ethanol / chemistry
Kinetics
Microscopy, Electron, Scanning
Models, Molecular*
Molecular Structure
Pregnenes / chemistry*
Solubility
Solvents / chemistry
Spectrum Analysis, Raman
Technology, Pharmaceutical
Temperature

Substances

(7alpha,17alpha)-17-hydroxy-7-methyl-19-nor-17-pergen-5(10)-en-20-yn-3-one steroid
Pregnenes
Solvents
Acetone
Ethanol