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Solid-Phase and Oscillating Solution Crystallization Behavior of (+)- and (-)-N-Methylephedrine.

Samuel Kofi Tulashie1, Daniel Polenske2, Andreas Seidel-Morgenstern3

  • 1University of Cape Coast, College of Agriculture and Natural Sciences, School of Physical Sciences, Department of Chemistry, Industrial Chemistry Unit, Cape Coast, Ghana; Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany.

Journal of Pharmaceutical Sciences
|September 24, 2016
PubMed
Summary

This study investigated N-methylephedrine enantiomer crystallization, identifying two solid-phase modifications and detailing solubility in different solvents. Successful preferential crystallization was achieved, offering insights into enantiomeric separation. Keywords: N-methylephedrine enantiomers, crystallization, solubility, preferential crystallization.

Keywords:
chiral resolutioninduction timepolymorphismpreferential crystallizationpreferential nucleationresolution by entrainmentsolubility data

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Area of Science:

  • Pharmaceutical Chemistry
  • Physical Chemistry
  • Crystallography

Background:

  • Understanding enantiomer crystallization is crucial for chiral drug development and separation.
  • N-methylephedrine enantiomers present complex crystallization behaviors influenced by solid-phase and solution conditions.

Purpose of the Study:

  • To systematically investigate the melt phase diagram and polymorphism of N-methylephedrine enantiomers.
  • To determine the solubility and ternary solubility phase diagrams in specific solvent systems.
  • To explore preferential nucleation and crystallization phenomena, including oscillatory behavior.

Main Methods:

  • Phase diagram analysis of the enantiomeric N-methylephedrine system, including melt crystallization.
  • Solubility measurements and ternary phase diagram construction in isopropanol:water and diethyl tartrate solvents.
  • Preferential nucleation and crystallization experiments under varying supersaturation levels.

Main Results:

  • Identification of two monotropically related polymorphic modifications of N-methylephedrine enantiomers.
  • Determination of solubility data and ternary solubility phase diagrams in the specified solvent systems and temperature ranges.
  • Observation of unusual oscillatory crystallization behavior at high supersaturation and successful preferential crystallization at lower supersaturation.

Conclusions:

  • The study elucidates the complex solid-phase and solution crystallization behavior of N-methylephedrine enantiomers.
  • The findings contribute to the understanding of polymorphism and solubility relevant to chiral compound crystallization.
  • Successful preferential crystallization demonstrates a viable method for enantiomeric separation of N-methylephedrine.