The polymorphism of azaperone and clotrimazole
Borka, L.; Valdimarsdottir, S.
Acta Pharmaceutica Suecica 12(5-6): 479-484
1975
ISSN/ISBN: 0001-6675 PMID: 1217501 Document Number: 576
The sedative drug azaperone and the antimycotic drug clotrimazole were investigated for the possible existence of polymorphism. Azaperone melts at 92-94.degree. C in its stable form; a new, unstable modification was prepared with m.p. 74.degree. C. The stability of this Form II is low, within 24 h it transforms into Form I. The addition of 11 common solvents to azaperone was investigated. Glacial acetic acid was strongest bound, but after a few weeks even this solvent was released from the crystals. Clotrimazole melts at 143-144.degree. C in its stable modification, Form I. A new, metastable modification, Form II with m.p. 106.degree. C has been isolated. The stability of this form is sufficient for the necessary manipulation for recording the IR spectrum. Heavy mechanical stress, leads to transformation into Form I. The IR spectra of Forms I and II differ in several details. Again, none of the 11 common solvents were bound to clotrimazole in stoichiometric ratios, but glacial acetic acid was released very slowly.
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