Doris E. Braun

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A fast and simple method for the quantitative analysis of monoclinic (form I) and orthorhombic (form II) paracetamol was developed, based on FT-Raman spectroscopy and PLS regression. Three different preprocessing algorithms, namely orthogonal signal correction (OSC), standard normal variate transformation (SNV) and multiplicative scatter correction (MSC),(More)
Morphine, codeine, and ethylmorphine are important drug compounds whose free bases and hydrochloride salts form stable hydrates. These compounds were used to systematically investigate the influence of the type of functional groups, the role of water molecules, and the Cl(-) counterion on molecular aggregation and solid state properties. Five new crystal(More)
Crystal structure prediction studies indicated the existence of an unknown high density monohydrate structure (Hy1B°) as global energy minimum for 4-aminoquinaldine (4-AQ). We thus performed an interdisciplinary experimental and computational study elucidating the crystal structures, solid form inter-relationships, kinetic and thermodynamic stabilities of(More)
Computational crystal structure prediction (CSP) methods can now be applied to the smaller pharmaceutical molecules currently in drug development. We review the recent uses of computed crystal energy landscapes for pharmaceuticals, concentrating on examples where they have been used in collaboration with industrial-style experimental solid form screening.(More)
BACKGROUND In solid state structures of organic molecules, identical sets of H-bond donor and acceptor functions can result in a range of distinct H-bond connectivity modes. Specifically, competing H-bond structures (HBSs) may differ in the quantitative proportion between one-point and multiple-point H-bond connections. For an assessment of such HBSs, the(More)
The crystal structure of the methanol hemisolvate of 5,5-dibromobarbituric acid (1MH) displays an H-bonded layer structure which is based on N-H⋯O=C, N-H⋯O(MeOH) and (MeOH)O-H⋯O interactions. The barbiturate molecules form an H-bonded substructure which has the fes topology. 5,5'-Methanediylbis(5-bromobarbituric acid) 2, obtained from a solution of(More)
We report the structure of the fifth monohydrate of gallic acid and two additional anhydrate polymorphs and evidence of at least 22 other solvates formed, many containing water and another solvent. This unprecedented number of monohydrate polymorphs and diversity of solid forms is consistent with the anhydrate and monohydrate crystal energy landscapes,(More)
A study of two dihydroxybenzoic acid isomers shows that computational methods can be used to predict hydrate formation, the compound:water ratio and hydrate crystal structures. The calculations also help identify a novel hydrate found in the solid form screening that validates this study.
New polymorphs of thymine emerged in an experimental search for solid forms, which was guided by the computationally generated crystal energy landscape. Three of the four anhydrates (AH) are homeoenergetic (A° - C) and their packing modes differ only in the location of oxygen and hydrogen atoms. AHs A° and B are ordered phases, whereas AH C shows disorder(More)
The complex interplay of temperature and water activity (aw) / relative humidity (RH) on the solid form stability and transformation pathways of three hydrates (HyA, HyB and HyC), an isostructural dehydrate (HyAdehy ), an anhydrate (AH) and amorphous brucine has been elucidated and the transformation enthalpies quantified. The dihydrate (HyA) shows a(More)