Abstract
Six metastable polymorphs (V, VII−XI) of phenobarbital (Pbtl) were produced by melt crystallization via seeding with corresponding isomorphic barbiturate homologues, following the teachings of earlier thermoanalytical studies of isopolymorphic relationships and utilizing the melting phase diagrams of Pbtl admixtures with various 5,5-substituted barbituric acid derivatives. The Pbtl forms and their solid solutions were analyzed with hot-stage microscopy, powder X-ray diffraction, and infrared spectroscopy. The crystal structures of several isomorphic homologues were determined to assess the structural features of the metastable Pbtl polymorphs. In contrast to Pbtl-V, VIII, and IX, which could be isolated as a single component phase, Pbtl-VII, X, and XI could only be stabilized in the presence of one of the isomorphic additives. Form Pbtl-V, the most stable form among the six metastable polymorphs, is structurally similar to Pbtl-IV and was crystallized by seeding with co-crystals of Pbtl/rutonal (3:1). Pbt...
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.