Crystallization Behavior of Carbamazepine

Tröbs, Lisa; Thi, Yen Nguyen; Rump, Doreen; Emmerling, Franziska

doi:10.1515/zpch-2013-0452

Cited by 4 publications

(5 citation statements)

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“…16,17 The type of acoustically levitation experiments highlighted here essentially relied on the monitorization of the droplet chemical composition, the droplet size, and the phases detected, as crystallization progresses. [16][17][18]28 The influence of surface cooling and the possible capture of atmospheric water by the droplet as the solvent evaporates have remained two unexplored issues. Previous experiments carried out with pure organic solvents suggest, however, that both these effects may be significant in an evaporative crystallization process.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Studies on acoustically levitated droplets with simultaneous real-time analysis using different techniques (synchrotron X-ray diffraction, Raman spectroscopy, and imaging) were also performed to investigate crystallization in a contactless environment and to identify intermediate stages preceding the final product. − A judicious choice of solvent enabled, for example, the selective isolation of metastable crystalline forms of ROY, 5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile . ROY is famous for its numerous colorful crystalline modifications that can be isolated in walled vessels. − Experiments with paracetamol showed that not only the container surface-free conditions, but specially the use of a specific solvent and the saturation degree during crystallization from solution, triggers and controls the selective formation of the thermodynamically stable form I and the metastable form II .…”

Section: Introductionmentioning

confidence: 99%

“…The type of acoustically levitation experiments highlighted here essentially relied on the monitorization of the droplet chemical composition, the droplet size, and the phases detected, as crystallization progresses. − , The influence of surface cooling and the possible capture of atmospheric water by the droplet as the solvent evaporates have remained two unexplored issues. Previous experiments carried out with pure organic solvents suggest, however, that both these effects may be significant in an evaporative crystallization process. − Their influence was, therefore, investigated in this work by adding thermographic analysis to the above mentioned techniques (X-ray diffraction, Raman spectroscopy, and imaging) and complementing the experimental information with MD simulation results.…”

Section: Introductionmentioning

confidence: 99%

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Real-Time In situ XRD Study of Simvastatin Crystallization in Levitated Droplets

Heilmann

Simões

Bernardes

et al. 2021

Crystal Growth & Design

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Simvastatin (SV) is an important active pharmaceutical ingredient (API) for treatment of hyperlipidemias, which is known to exist in different crystalline and amorphous phases. It is, therefore, an interesting model to investigate how the outcome of evaporative crystallization in the contactless environment of an acoustically levitated droplet may be influenced by key experimental conditions, such as temperature, solvent properties (e.g., polarity and hygroscopicity), and dynamics of the evaporation process. Here, we describe a real-time and in situ study of simvastatin evaporative crystallization from droplets of three solvents that differ in volatility, polarity, and protic character (acetone, ethanol, and ethyl acetate). The droplet monitorization relied on synchrotron X-ray diffraction (XRD), Raman spectroscopy, imaging, and thermographic analysis. A pronounced solvent-dependent behavior was observed. In ethanol, a simvastatin amorphous gel-like material was produced, which showed no tendency for crystallization over time; in ethyl acetate, a glassy material was formed, which crystallized on storage over a two-week period to yield simvastatin form I; and in acetone, form I crystallized upon solvent evaporation without any evident presence of a stable amorphous intermediate. The XRD and Raman results further suggested that the persistent amorphous phase obtained from ethanol and the amorphous precrystallization intermediate formed in ethyl acetate were similar. Thermographic analysis indicated that the evaporation process was accompanied by a considerable temperature decrease of the droplet surface, whose magnitude and rate correlated with the solvent volatility (acetone > ethyl acetate > ethanol). The combined thermographic and XRD results also suggested that, as the cooling effect increased, so did the amount of residual water (most likely captured from the atmosphere) remaining in the droplet after the organic solvent was lost. Finally, the interpretation of the water fingerprint in the XRD time profiles was aided by molecular dynamics simulations, which also provided insights into the possible role of H2O as an antisolvent that facilitates simvastatin crystallization.

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Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Real-Time In situ XRD Study of Simvastatin Crystallization in Levitated Droplets

Heilmann

Simões

Bernardes

et al. 2021

Crystal Growth & Design

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“…A further advantage of the contact-less sample environment offered by ultrasonic levitation is the ready application of different analytical techniques. It has been combined with methods such as FTIR, Raman spectroscopy, and microscopy as well as UV–visible spectroscopy. − There are few examples of the coupling of ultrasonic levitation with small-angle X-ray scattering (SAXS); it has been applied to the study of the growth mechanism of inorganic and organic crystals, , the agglomeration of soluble proteins, and the structures of glassy materials . It is reasonably straightforward to combine several techniques with ultrasonic levitation to analyze the same sample simultaneously.…”

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confidence: 99%

Control of Nanomaterial Self-Assembly in Ultrasonically Levitated Droplets

Seddon

Richardson

Rastogi

et al. 2016

J. Phys. Chem. Lett.

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We demonstrate that acoustic trapping can be used to levitate and manipulate droplets of soft matter, in particular, lyotropic mesophases formed from self-assembly of different surfactants and lipids, which can be analyzed in a contact-less manner by X-ray scattering in a controlled gas-phase environment. On the macroscopic length scale, the dimensions and the orientation of the particle are shaped by the ultrasonic field, while on the microscopic length scale the nanostructure can be controlled by varying the humidity of the atmosphere around the droplet. We demonstrate levitation and in situ phase transitions of micellar, hexagonal, bicontinuous cubic, and lamellar phases. The technique opens up a wide range of new experimental approaches of fundamental importance for environmental, biological, and chemical research.

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“…To access these levels of supersaturation any container walls which might act as heterogeneous nucleation sites have to be circumvented. In the past few years, acoustic levitators generating an ultrasonic standing wave for the containerless levitation of objects, such as droplets or solid samples, have gained considerable interest to study crystallization processes [15][16][17][18][19][20][21][22][23][24][25][26]. We briefly describe the experimental development up to the introduction of a climate unit for the control of the chemical potential of the surrounding vapor phase [27].…”

Section: Introductionmentioning

confidence: 99%

Control of organic polymorph formation: crystallization pathways in acoustically levitated droplets

Nguyen

Roessler

Rademann

et al. 2016

Zeitschrift Für Kristallographie - Crystalline Materials

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Abstract:Theoretical and experimental studies indicate that crystal nucleation can take more complex pathways than expected on the ground of the classical nucleation theory. Among these pathways are the formation of prenucleation clusters and amorphous precursor phases. A direct in situ observation of the different pathways of nucleation from solution is challenging since the paths can be influenced by heterogeneous nucleation sites, such as container walls. Here, we provide insights into the crystallization process using the in situ combination of an acoustic levitator, Raman spectroscopy, and X-ray scattering. The contactless sample holder enables the observation of homogeneous crystallization processes and the detection of intermediates and final crystalline forms. We provide evidence for the existence of multiple pathways of nucleation based on the investigation of the crystallization of organic molecules from different solvents. Starting from a diluted solution, a supersaturation is reached during the experiment due to the evaporation of the solvent. The highly supersaturated solution reveals different pathways of crystallization. Depending on the degree of supersaturation either the thermodynamically stable or the metastable crystal form is observed.

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Crystallization Behavior of Carbamazepine

Cited by 4 publications

References 0 publications

Real-Time In situ XRD Study of Simvastatin Crystallization in Levitated Droplets

Real-Time In situ XRD Study of Simvastatin Crystallization in Levitated Droplets

Control of Nanomaterial Self-Assembly in Ultrasonically Levitated Droplets

Control of organic polymorph formation: crystallization pathways in acoustically levitated droplets

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