scholarly journals Combined crystal structure prediction and high-pressure crystallization in rational pharmaceutical polymorph screening

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
M. A. Neumann ◽  
J. van de Streek ◽  
F. P. A. Fabbiani ◽  
P. Hidber ◽  
O. Grassmann
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Structure Prediction ◽  
Crystal Structure Prediction ◽  
Pressure Crystallization ◽  
Polymorph Screening

scholarly journals New high-pressure phases of Fe7N3 and Fe7C3 stable at Earth's core conditions: evidences for carbon–nitrogen isomorphism in Fe-compounds

RSC Advances ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 3577-3581 ◽  
Author(s):  
Nursultan Sagatov ◽  
Pavel N. Gavryushkin ◽  
Talgat M. Inerbaev ◽  
Konstantin D. Litasov
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Ab Initio ◽  
Structure Prediction ◽  
Harmonic Approximation ◽  
Crystal Structure Prediction ◽  
Earth’S Core ◽  
Earth's Core ◽  
Core Conditions

We carried out ab initio calculations on the crystal structure prediction and determination of P–T diagrams within the quasi-harmonic approximation for Fe7N3 and Fe7C3.

scholarly journals Minimizing Polymorphic Risk Through Cooperative Computational and Experimental Exploration

2020 ◽  
Author(s):  
Christopher R. Taylor ◽  
Matthew T. Mulvee ◽  
Domonkos S. Perenyi ◽  
Michael R. Probert ◽  
Graeme Day ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Structure Prediction ◽  
Experimental Approach ◽  
Significant Risk ◽  
Free Energy Calculations ◽  
Crystal Structure Prediction ◽  
Crystal Forms ◽  
Wide Range ◽  
Solid Form

<div> <p>We combine state-of-the-art computational crystal structure prediction (CSP) techniques with a wide range of experimental crystallization methods to understand and explore crystal structure in pharmaceuticals and minimize the risk of unanticipated late-appearing polymorphs. Initially, we demonstrate the power of CSP to rationalize the difficulty in obtaining polymorphs of the well-known pharmaceutical isoniazid and show that CSP provides the structure of the recently discovered, but unsolved, Form III of this drug despite there being only a single known form for almost 70 years. More dramatically, our blind CSP study predicts a significant risk of polymorphism for the related iproniazid. Employing a wide variety of experimental techniques, including high-pressure experiments, we experimentally obtained the first three known non-solvated crystal forms of iproniazid, all of which were successfully predicted in the CSP procedure. We demonstrate the power of CSP methods and free energy calculations to rationalize the observed elusiveness of the third form of iproniazid, the success of high-pressure experiments in obtaining it, and the ability of our synergistic computational-experimental approach to “de-risk” solid form landscapes.</p> </div>

Crystal structure prediction of ReN2 under high pressure

2019 ◽  
Vol 94 (11) ◽  
pp. 1711-1716
Author(s):  
H. Y. Wang ◽  
P. Yan ◽  
L. Xu ◽  
D. W. Zhou ◽  
D. Li
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Structure Prediction ◽  
Crystal Structure Prediction

scholarly journals Unbiased crystal structure prediction of NiSi under high pressure

2015 ◽  
Vol 48 (3) ◽  
pp. 906-908 ◽  
Author(s):  
Pavel N. Gavryushkin ◽  
Zakhar I. Popov ◽  
Konstantin D. Litasov ◽  
Alex Gavryushkin
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Structure Prediction ◽  
Type Structure ◽  
Stable Phase ◽  
Stable Form ◽  
Model Structure ◽  
Crystal Structure Prediction ◽  
Cscl Type ◽  
Pressure Phase

On the basis of an unbiased structure prediction, it is shown that the stable form of NiSi under pressures of 100 and 200 GPa is thePmmnstructure. Furthermore, a new stable phase has been discovered: the deformed tetragonal CsCl-type structure witha= 2.174 Å andc= 2.69 Å at 400 GPa. Specifically, the sequence of high-pressure phase transitions is the following: thePmmnstructure below 213 GPa, the tetragonal CsCl type in the range 213–522 GPa, and cubic CsCl higher than 522 GPa. As the CsCl-type structure is considered as the model structure of the FeSi compound at the conditions of the Earth's core, this result implies restrictions on the Fe–Ni isomorphic miscibility in FeSi.

Crystal structure prediction of uranium hydrides at high pressure: A new hydrogen-rich phase

2018 ◽  
Vol 382 (40) ◽  
pp. 2959-2964 ◽  
Author(s):  
Xiaohui Wang ◽  
Menglei Li ◽  
Fawei Zheng ◽  
Ping Zhang
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Structure Prediction ◽  
Crystal Structure Prediction ◽  
Rich Phase

scholarly journals CRYSTAL STRUCTURE PREDICTION IN THE CONTEXT OF PHARMACEUTICAL POLYMORPH SCREENING AND PUTATIVE POLYMORPHS OF CIPROFLOXACIN

2017 ◽  
Vol 9 (4) ◽  
pp. 1
Author(s):  
Pawanpreet Singh ◽  
Renu Chadha
Keyword(s):  
Crystal Structure ◽  
Pharmaceutical Industry ◽  
Structure Prediction ◽  
Active Pharmaceutical Ingredient ◽  
Crystal Form ◽  
Crystal Structure Prediction ◽  
Drug Polymorphism ◽  
Computational Aspects ◽  
Polymorph Screening

Molecular simulation is increasingly used by medicinal chemists in the process and product development. Reliable computational predictions are of great value not only for the design of an active pharmaceutical ingredient with novel properties but also for the avoidance of an undesirable change of form in the late stages of development of an industrially important molecule. In the pharmaceutical industry, drug polymorphism can be a critical problem and is the subject of various regulatory considerations. This contribution tried to review the fuzzy frontiers between the chemical structure of the molecule and its crystal energy landscape with a particular focus on the crystal structure prediction (csp) methodology to complement polymorph screening. A detailed application of csp in the pharmaceutical industry is illustrated on ciprofloxacin; describing its putative polymorphs. This approach successfully identifies the known crystal form within this class, as well as a large number of other low-energy structures. The performance of the approach is discussed in terms of both the quality of the results and computational aspects. csp methods are now being used as part of the interdisciplinary range of studies to establish the range of solid forms of a molecule. Moreover, further methodological improvements aimed at increasing the accuracy of the predictions and at broadening the range of molecules i.e. cocrystals, salts and solvates.

Mg2Si under Pressure: DFT Evolutionary Search Results

2016 ◽  
Vol 247 ◽  
pp. 9-16 ◽  
Author(s):  
Yuri V. Luniakov
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Structure Prediction ◽  
Pressure Range ◽  
Function Theory ◽  
Density Function Theory ◽  
Evolutionary Search ◽  
Crystal Structure Prediction ◽  
Search Results ◽  
Evolutionary Simulations

Using density function theory (DFT), evolutionary simulations for crystal structure prediction, the most stable compositions of Mg2Si in the pressure range 0–30 GPa were obtained. The DFT results reproduce experimentally observed pressure-induced phase transitions and predict a new high-pressure structure Cmcm (space group 63).

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