Raman spectroscopy: Recent advancements, techniques and applications

Das, Ruchita S.; Agrawal, Y. K.

doi:10.1016/j.vibspec.2011.08.003

“…[ [25][26][27][28][29] A spectral region between 500-1800 cm −1 and 2500-3500 cm −1 was selected for raman analysis of aceclofenac in crystalline and solution forms as shown in Figures 8 and 9.…”

Section: Raman Spectroscopic Analysismentioning

confidence: 99%

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Solanki

¹

2017

AJP

0

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Context: Water solubility is an important molecular property for successful drug development as it is a key factor governing drug access to biological membranes. The solubilization of poorly water soluble drug by facilitated mixed solvency is presented. Aim: The aim was to develop the injection formulations of the model poorly water-soluble drug. Settings and Design: Trial and error based experimental study. Materials and Methods: Mixed solvency approach was used to solubilize the hydrophobic drug. Mixed solvent system prepared using water-soluble hydrotropes (such as sodium citrate and urea) and water-miscible cosolvents, such as polyethylene glycol (PEG) 200, PEG 300, PEG 400, PEG 600, glycerin, propylene glycol, and ethanol. Drug was characterized using ultraviolet, Fourier Transform infrared (FT-IR), and Raman spectroscopy. Solubilizing power (Φ) and the Gibbs free energy of transfer (ΔG 0 tr) were determined. Various properties of solution such as pH, viscosity, specific gravity, and refractive index were also studied. Results: Desired solubility of drug achieved in a mixed solvent blend AF5, which was more than 200 fold as compared to the solubility in distilled water 0.152 mg/ml. Drug content was found to be more than 98%. FT-IR and Raman spectroscopy results may support intermolecular hydrogen bonding between drug and mixed solvent system. Developed formulation was physically and chemically stable. Conclusion: This technique proved a synergistic enhancement in solubility of a poorly water soluble drug due to mixed solvent effect and produces a stable formulation. Mixed solvency concept may reduce the individual concentration of solubilizers and so reduce their toxicity associated with them.

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“…where the elements of f (4) r are identified with the three distinct isomers of the rank-4 isotropic tensor in the laboratory frame (denoted by Latin indices), m (4) r s is the collective numerical coefficients, and g (4) s denotes the three analogous rank-4 isotropic tensor isomers that are in the molecular frame (Greek indices). The polarizations associated with the incident and scattered light are identical in each term, and hence, the relevant part of the 45 terms determined from Equation (5) is treated similarly; the following common factor is thus obtained 31…”

Section: (4)mentioning

confidence: 99%

“…4(a) and 4(b), respectively), as often employed in measuring a depolarization ratio. 32 By adopting these two polarization schemes, numerical results can be obtained from Equation (30) and contracted with the numerical matrix, m (4) r s , in Equation (29). Therefore, the parallel configuration produces the expression P = 1 15…”

Section: (4)mentioning

confidence: 99%

“…These expressions are to be contracted with the molecular response tensors formed out of g (4) s seen in Equation (29) along with the molecular response tensors {α, α ′ , α ′′ , β, χ, χ ′ } from the product of the appropriate matrix elements, to form a new complementary tensor now defined as T w , to appear in the following final result…”

Section: (4)mentioning

confidence: 99%

“…Raman scattering involving individual optical centers is a well-established molecular process used as a spectroscopic [1][2][3] and microscopic tool 4,5 with an ever-increasing range of applications, including surface-enhanced spectroscopy, [6][7][8][9][10][11] sensing, [12][13][14] the detection of environmental pollutants, 15,16 and identification of disease. 17 The theoretical basis for the underlying phenomenon is well-known and established with quantum electrodynamical techniques offering a particularly insightful means of formulation.…”

Section: Introductionmentioning

confidence: 99%

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Raman scattering mediated by neighboring molecules

Williams

¹

,

Andrews

²

2016

The Journal of Chemical Physics

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Raman scattering is most commonly associated with a change in vibrational state within individual molecules, the corresponding frequency shift in the scattered light affording a key way of identifying material structures. In theories where both matter and light are treated quantum mechanically, the fundamental scattering process is represented as the concurrent annihilation of a photon from one radiation mode and creation of another in a different mode. Developing this quantum electrodynamical formulation, the focus of the present work is on the spectroscopic consequences of electrodynamic coupling between neighboring molecules or other kinds of optical center. To encompass these nanoscale interactions, through which the molecular states evolve under the dual influence of the input light and local fields, this work identifies and determines two major mechanisms for each of which different selection rules apply. The constituent optical centers are considered to be chemically different and held in a fixed orientation with respect to each other, either as two components of a larger molecule or a molecular assembly that can undergo free rotation in a fluid medium or as parts of a larger, solid material. The two centers are considered to be separated beyond wavefunction overlap but close enough together to fall within an optical near-field limit, which leads to high inverse power dependences on their local separation. In this investigation, individual centers undergo a Stokes transition, whilst each neighbor of a different species remains in its original electronic and vibrational state. Analogous principles are applicable for the anti-Stokes case. The analysis concludes by considering the experimental consequences of applying this spectroscopic interpretation to fluid media; explicitly, the selection rules and the impact of pressure on the radiant intensity of this process

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Visualization Techniques in Process Engineering

Mewes¹

2013

Ullmann's Encyclopedia of Industrial Chemistry

1

0

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The article contains sections titled: 1. Introduction 2. Optical Visualization Techniques 3. Tomographic Visualization Techniques 3.1. Tomographic Measurements and Data Analysis 3.2. Conductive Tomography 3.3. Capacitance Tomography 3.4. Optical Tomography 3.5. X‐Ray Tomography 3.6. Nuclear Magnetic Resonance (NMR) 4. Applications of Tomography 5. Future Perspectives

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Raman spectroscopy: Recent advancements, techniques and applications

Cited by 524 publications

References 188 publications

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Raman scattering mediated by neighboring molecules

Visualization Techniques in Process Engineering

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