Far-Infrared Spectroscopy as a Probe for Polymorph Discrimination

Pharmaceutical crystalline polymorph and amorphous form detection and quantification is a standard requirement in the pharmaceutical industry. Infrared (IR) spectroscopy provides an important probe for the characterization of polymorphs. Nonetheless, characterization and discrimination among polymorphs using mid-IR spectroscopy is not always possible in part because the technique mainly probes vibrational modes arising from functional groups in the sample. In the present work, far-IR spectroscopy is demonstrated for the discrimination of polymorphs. This region is influenced by delocalized lattice vibrational modes derived from intermolecular forces and packing arrangements in the crystal structure. A total of 10 polymorphic pharmaceuticals were prepared to conduct a critical evaluation of the question, does this far-IR region add value for polymorph differentiation? It is demonstrated that the far-IR region offers high discriminating power for polymorphs compared to the mid-IR spectral region. In addition, structural similarity and dissimilarity in polymorphic packing arrangements can be derived from this analysis.

Techniques for dissecting adult aleocharine beetles (Coleoptera: Staphylinidae)

Methodology for detailed dissections of the phylogenetically most informative structures from adult aleocharine staphylinid beetles is provided. These methods include specimen preparation, relaxation, clearing, bleaching, dehydration and full dissection. A detailed summary of mouthpart and male and female genitalic dissections is provided. Recently described character systems, including those of the mouthparts and the thoracic regions, have been successfully used in phylogenetic studies of aleocharine staphylinids. This paper provides the first thorough description of the techniques necessary to reveal these character systems.