EXPO software for solving crystal structures by powder diffraction data: methods and application

Altomare, Angela; Corriero, Nicola; Cuocci, Corrado; Falcicchio, Aurelia; Moliterni, Anna; Rizzi, Rosanna

doi:10.1002/crat.201500024

Cited by 41 publications

(24 citation statements)

References 14 publications

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“…8. The Bragg angles, the inter-reticular distances and the Miller indices of the eutectic mixture, as well as the pure compounds, were evaluated by the EXPO 2014 software [54].…”

Section: X-ray Diffraction Analysis (Xrd)mentioning

confidence: 99%

Solid + liquid equilibria and molecular structure studies of binary mixtures for nitrate ester’s stabilizers: Measurement and modeling

et al. 2018

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A B S T R A C TSolid-liquid equilibria (SLE) data for two binary organic mixtures of N-(2-methoxyethyl)-p-nitroaniline + Nethyl-4-nitroaniline (S1) and N-(2-ethanol)-p-nitroaniline + N-ethyl-4-nitroaniline (S2) have been measured using differential scanning calorimeter to build the corresponding solid-liquid phase diagrams. The quality of the SLE data has been checked by consistency tests, presenting good quality factors for both systems. Simple eutectic behavior has been observed for these systems with the presence of a solid-solid transition for S2. The SLE data have been correlated by means of Wilson, NRTL, and UNIQUAC equations. The used models calculate the equilibrium temperatures very satisfactorily. The best modeling results were obtained using the Wilson equation with a root mean square deviation between experimental and calculated values for S1 and S2 of 1.15 and 1.99, respectively. The Wilson, NRTL, and UNIQUAC equations have also been used to compute excess thermodynamic functions viz. excess Gibbs energy, enthalpy, and entropy. The obtained results demonstrated a moderate positive deviation to ideality for S1, and a strong positive deviation for S2, unveiling the nature of the interactions between the compounds forming each mixture. In addition, microstructural studies have been carried out by FTIR, XRD and optical microscopy. Weak molecular interactions have been shown for the eutectic compositions. Jackson's roughness parameter was calculated and found to be greater than 2, suggesting the faceted morphology with irregular structures.

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“…8. The Bragg angles, the inter-reticular distances and the Miller indices of the eutectic mixture, as well as the pure compounds, were evaluated by the EXPO 2014 software [54].…”

Section: X-ray Diffraction Analysis (Xrd)mentioning

confidence: 99%

Solid + liquid equilibria and molecular structure studies of binary mixtures for nitrate ester’s stabilizers: Measurement and modeling

et al. 2018

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“…7. The Bragg angles, the inter-reticular distances and the Miller indices of the eutectic mixture, as well as those of the pure compounds, were evaluated by the EXPO 2014 software [38].…”

Section: X-ray Diffraction Analysis (Xrd)mentioning

confidence: 99%

Solid–Liquid Phase Equilibria, Molecular Interaction and Microstructural Studies on (N-(2-ethanol)-p-nitroaniline + N-(2-acetoxyethyl)-p-nitroaniline) Binary Mixtures

et al. 2018

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Differential scanning calorimetry (DSC) is used to investigate the thermal properties of N-(2-ethanol)-p-nitroaniline + N-(2-acetoxyethyl)-p-nitroaniline, and their binary systems. The experimental results demonstrate that the studied binary system presents a simple eutectic behavior and the corresponding mole fraction (x eu) of N-(2-ethanol)p-nitroaniline at the eutectic point is 0.5486, whereas the temperature (T eu) is found to be equal to 363.6 K. The quality of the solid-liquid equilibria (SLE) data has been checked by thermodynamic consistency tests, presenting good quality factor. The SLE data have been correlated by means of Wilson, NRTL, and UNIQUAC equations. The three models describe satisfactorily the phase diagram as the root-mean-square deviations for the equilibrium temperatures vary from 1.25 K to 2.07 K. Nevertheless, the Wilson model provides the best correlation results. The three equations have also been used to compute excess thermodynamic functions viz. excess Gibbs energy, enthalpy and entropy. The obtained results revealed a sensitive positive deviation to ideality thus demonstrating the nature of the interactions between the compounds forming the mixture. Microstructural studies have been carried out by FTIR, XRD and optical microscopy showing weak molecular interactions for the eutectic mixture.

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“…While SCXRD provides detailed structural information including the lattice parameters, space group, miller indices, crystal system, unit cell volume, inter and intramolecular interactions, the PXRD provides information about the crystallinity of the solid phase. However, when the crystals produced by solution crystallization are not of good quality to conduct SCXRD analysis, one can possibly extract the structural data from PXRD data using indexing programs such as TREOR90 [ 200 ], ITO [ 201 ] and AUTOX [ 202 ], DASH [ 203 ], Rex.Cell [ 204 ] and Rietveld refinement programs such as TOPAS [ 205 ] and EXPO [ 206 ]. International Union of Crystallography (IUCr) serves as a valuable resource, containing information about different crystallographic software used for determining single crystal data of cocrystals from their corresponding PXRD data [ 207 ].…”

Section: Characterization Of Cocrystalsmentioning

confidence: 99%

Engineering Cocrystals of Poorly Water-Soluble Drugs to Enhance Dissolution in Aqueous Medium

2018

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Biopharmaceutics Classification System (BCS) Class II and IV drugs suffer from poor aqueous solubility and hence low bioavailability. Most of these drugs are hydrophobic and cannot be developed into a pharmaceutical formulation due to their poor aqueous solubility. One of the ways to enhance the aqueous solubility of poorlywater-soluble drugs is to use the principles of crystal engineering to formulate cocrystals of these molecules with water-soluble molecules (which are generally called coformers). Many researchers have shown that the cocrystals significantly enhance the aqueous solubility of poorly water-soluble drugs. In this review, we present a consolidated account of reports available in the literature related to the cocrystallization of poorly water-soluble drugs. The current practice to formulate new drug cocrystals with enhanced solubility involves a lot of empiricism. Therefore, in this work, attempts have been made to understand a general framework involved in successful (and unsuccessful) cocrystallization events which can yield different solid forms such as cocrystals, cocrystal polymorphs, cocrystal hydrates/solvates, salts, coamorphous solids, eutectics and solid solutions. The rationale behind screening suitable coformers for cocrystallization has been explained based on the rules of five i.e., hydrogen bonding, halogen bonding (and in general non-covalent bonding), length of carbon chain, molecular recognition points and coformer aqueous solubility. Different techniques to screen coformers for effective cocrystallization and methods to synthesize cocrystals have been discussed. Recent advances in technologies for continuous and solvent-free production of cocrystals have also been discussed. Furthermore, mechanisms involved in solubilization of these solid forms and the parameters influencing dissolution and stability of specific solid forms have been discussed. Overall, this review provides a consolidated account of the rationale for design of cocrystals, past efforts, recent developments and future perspectives for cocrystallization research which will be extremely useful for researchers working in pharmaceutical formulation development.

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EXPO software for solving crystal structures by powder diffraction data: methods and application

Cited by 41 publications

References 14 publications

Solid + liquid equilibria and molecular structure studies of binary mixtures for nitrate ester’s stabilizers: Measurement and modeling

Solid + liquid equilibria and molecular structure studies of binary mixtures for nitrate ester’s stabilizers: Measurement and modeling

Solid–Liquid Phase Equilibria, Molecular Interaction and Microstructural Studies on (N-(2-ethanol)-p-nitroaniline + N-(2-acetoxyethyl)-p-nitroaniline) Binary Mixtures

Engineering Cocrystals of Poorly Water-Soluble Drugs to Enhance Dissolution in Aqueous Medium

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