Raman Spectroscopy in Disordered Molecular Compounds: Application to Pharmaceuticals

Hédoux, Alain

doi:10.1002/9783527652693.ch12

Cited by 3 publications

(2 citation statements)

References 72 publications

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“…This conclusion is based on the general shape of the spectral features (weak and broad features), where the positions of these features seem to be a combination of the known anhydrate forms I, II and III [26]. As a consequence of random short-to mid-range order in the non-crystalline state, a Raman spectrum of an amorphous drug will consist of weak and broadened shifts at the same positions as the crystalline forms of the drug [28]. The combination of shifts is especially evident in the region of 1500-1650 cm −1 , where 6 peaks are visible for the form resolved in component 3.…”

Section: Solid Forms Detected In the Molten Polymer Mixturesmentioning

confidence: 99%

Exploring the Complexity of Processing-Induced Dehydration during Hot Melt Extrusion Using In-Line Raman Spectroscopy

et al. 2020

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The specific aim in this study was to understand the effect of critical process parameters on the solid form composition of model drug compounds during hot melt extrusion using in-line Raman spectroscopy combined with Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) modeling for semi-quantitative kinetic profiling. It was observed that the hydrate and anhydrate solid forms of two model drugs in the melts of nitrofurantoin (NF):polyethylene oxide (PEO) and piroxicam (PRX):PEO could be resolved from a MCR-ALS model without an external calibration dataset. Based on this model, the influence of two critical process parameters (shear and temperature) on the solid form composition could be evaluated in a real-time mode and the kinetics of complex transformation pathways could be explored. Additionally, the dehydration pathways of NF monohydrate and PRX monohydrate in molten PEO could be derived. It can be concluded that dehydration of both hydrates in PEO occurs via competing mechanisms—a solution-mediated transformation pathway and a solid–solid transformation, and that the balance between these mechanisms is determined by the combined effect of both temperature and shear. Another important observation was that the water released from these hydrate compounds has a detectable effect on the rheological characteristics of this mixture.

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Section: Solid Forms Detected In the Molten Polymer Mixturesmentioning

confidence: 99%

Exploring the Complexity of Processing-Induced Dehydration during Hot Melt Extrusion Using In-Line Raman Spectroscopy

et al. 2020

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“…The majority of these methods characterize a solid at the surface or particulate level such as isothermal micro-calorimetry, dynamic vapor sorption, , atomic force microscopy, , and transmission electron microscopy . The characterization of disorder at the molecular level in the bulk is currently limited to powder XRD , and some spectroscopic methods such as solid-state NMR, − Raman, and dielectric spectroscopy . Single crystal XRD is a fundamental method in crystallography that provides detailed information about the internal lattice of a crystalline material and the nature of the disorder; − however, it is not a bulk analysis method .…”

Section: Introductionmentioning

confidence: 99%

Combining X-ray and NMR Crystallography to Explore the Crystallographic Disorder in Salbutamol Oxalate

Al-Ani

Szell

Rehman

et al. 2022

Crystal Growth & Design

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Salbutamol is an active pharmaceutical ingredient commonly used to treat respiratory distress and is listed by the World Health Organization as an essential medicine. Here, we establish the crystal structure of its oxalate form, salbutamol oxalate, and explore the nature of its crystallographic disorder by combined X-ray crystallography and 13 C cross-polarization (CP) magic-angle spinning (MAS) solid-state NMR. The *C−OH chiral center of salbutamol (note that the crystal structures are a racemic mixture of the two enantiomers of salbutamol) is disordered over two positions, and the tert-butyl group is rotating rapidly, as revealed by 13 C solid-state NMR. The impact of crystallization conditions on the disorder was investigated, finding variations in the occupancy ratio of the *C−OH chiral center between single crystals and a consistency across samples in the bulk powder. Overall, this work highlights the contrast between investigating crystallographic disorder by X-ray diffraction and solid-state NMR experiment, and gauge-including projector-augmented-wave (GIPAW) density functional theory (DFT) calculations, with their combined use, yielding an improved understanding of the nature of the crystallographic disorder between the local (i.e., as viewed by NMR) and longer-range periodic (i.e., as viewed by diffraction) scale.

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Reduced Graphene Oxide Loaded with ZCF Magnetic Nanoparticles as a Promising Photocatalyst and Antibacterial Agent

Abuzeyad,

El-Khawaga,

Tantawy

et al. 2024

J Clust Sci

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Due to waste, pollution, and unequal distribution of the world’s finite freshwater resources, there is currently a problem of water scarcity. Therefore, developing novel, affordable, and efficient techniques for water purification is essential. Here, the photo-assisted degradation of Methyl Orange dye (MO) under visible light and UV was achieved by using reduced graphene oxide (RGO) photocatalyst loaded with Zn0.5Cu0.5Fe2O4 (ZCF) called MRGO 20. Furthermore, all prepared samples were characterized by X-ray diffraction (XRD), fourier transformation infrared (FTIR), transmission electron microscope (TEM), vibrating sample magnetometer (VSM) and Raman analysis. After 40 minutes, the high photocatalytic efficacy effectively eliminated about 96 % of the 10 ppm MO using 20 mg of MRGO 20 NPs at pH 5 under Visible light irradiation. From the results, MRGO 20 demonstrated good performance stability after five cycles of photocatalytic degradation of MO dye. The shown performance of the generated samples in both visible and UV light may motivate further investigation into more potent photocatalysts for water filtering. MRGO 20 NPs nanocomposite displayed great activity against Gram-negative (E. coli) bacteria with a zone of inhibition (ZOI) mm value of 24.0 mm, and high biofilm inhibition of 94.3%. The produced samples’ observed efficacy in both UV and visible light may encourage continued research into more effective photocatalysts for the filtration of water and for biological applications.

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Raman Spectroscopy in Disordered Molecular Compounds: Application to Pharmaceuticals

Cited by 3 publications

References 72 publications

Exploring the Complexity of Processing-Induced Dehydration during Hot Melt Extrusion Using In-Line Raman Spectroscopy

Exploring the Complexity of Processing-Induced Dehydration during Hot Melt Extrusion Using In-Line Raman Spectroscopy

Combining X-ray and NMR Crystallography to Explore the Crystallographic Disorder in Salbutamol Oxalate

Reduced Graphene Oxide Loaded with ZCF Magnetic Nanoparticles as a Promising Photocatalyst and Antibacterial Agent

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