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Crystallization and polymorphic transitions of chlorpropamide in aqueous 2-hydroxybutyl-beta-cyclodextrin solution.

Takako Ishiguro¹, Fumitoshi Hirayama, Daisuke Iohara

¹Faculty of Pharmaceutical Sciences, Sojo University, 4-22-1 Ikeda, Kumamoto 860-0082, Japan; Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Kumamoto 862-0973, Japan.

European Journal of Pharmaceutical Sciences : Official Journal of the European Federation for Pharmaceutical Sciences

|December 29, 2009

Summary

2-hydroxybutyl-beta-cyclodextrin selectively controls chlorpropamide crystallization, yielding metastable polymorphs. This cyclodextrin derivative offers a novel method for preparing specific crystal forms during drug development.

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Area of Science:

Pharmaceutical Sciences
Physical Chemistry
Materials Science

Background:

Chlorpropamide exhibits polymorphism, with different crystal forms impacting drug properties.
Understanding crystallization mechanisms is crucial for controlling drug product quality and efficacy.

Purpose of the Study:

To investigate the effects of 2-hydroxybutyl-beta-cyclodextrin on chlorpropamide crystallization.
To elucidate the polymorphic transition mechanism of chlorpropamide in aqueous solution.

Main Methods:

Crystallization experiments of chlorpropamide in aqueous solution with varying concentrations of 2-hydroxybutyl-beta-cyclodextrin.
Analysis of polymorph formation and transitions under different temperature and concentration conditions.

Main Results:

2-hydroxybutyl-beta-cyclodextrin directed crystallization towards metastable Form II and III polymorphs at 4°C.
The specific metastable polymorph (II or III) was dependent on the cyclodextrin concentration.
The cyclodextrin inhibited polymorphic transitions, including Form II to Form III and Form III to Form A.

Conclusions:

2-hydroxybutyl-beta-cyclodextrin enables selective preparation of metastable chlorpropamide polymorphs.
The study provides insights into controlling crystallization pathways based on Ostwald's Rule of Stages.
This finding has implications for the targeted synthesis of specific drug crystal forms.