Investigation into the subambient behavior of aqueous mannitol solutions using temperature-controlled Raman microscopy

Beattie, J. Renwick; Barrett, Lindsay J.; Malone, John F.; McGarvey, John J.; Nieuwenhuyzen, Mark; Kett, Vicky L.

doi:10.1016/j.ejpb.2007.03.015

Cited by 19 publications

(14 citation statements)

References 25 publications

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“…From these observations and the HPLC and 1 H-NMR data, we propose that these two spectra correspond to two distinct crystal solid-state forms of THCa. Large variations in the vibrational spectra between multiple crystal forms of the same compound are not unheard-of, as has been shown with spontaneous Raman for mannitol 21 and lactose. 22 …”

Section: δ 9 -Tetrahydrocannabinolic Acidmentioning

confidence: 73%

In plantaimaging of Δ9-tetrahydrocannabinolic acid inCannabis sativa L.with hyperspectral coherent anti-Stokes Raman scattering microscopy

et al. 2013

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Abstract. Nature has developed many pathways to produce medicinal products of extraordinary potency and specificity with significantly higher efficiencies than current synthetic methods can achieve. Identification of these mechanisms and their precise locations within plants could substantially increase the yield of a number of natural pharmaceutics. We report label-free imaging of Δ 9 -tetrahydrocannabinolic acid (THCa) in Cannabis sativa L. using coherent anti-Stokes Raman scattering microscopy. In line with previous observations we find high concentrations of THCa in pistillate flowering bodies and relatively low amounts within flowering bracts. Surprisingly, we find differences in the local morphologies of the THCa-containing bodies: organelles within bracts are large, diffuse, and spheroidal, whereas in pistillate flowers they are generally compact, dense, and have heterogeneous structures. We have also identified two distinct vibrational signatures associated with THCa, both in pure crystalline form and within Cannabis plants; at present the exact natures of these spectra remain an open question. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Section: δ 9 -Tetrahydrocannabinolic Acidmentioning

confidence: 73%

In plantaimaging of Δ9-tetrahydrocannabinolic acid inCannabis sativa L.with hyperspectral coherent anti-Stokes Raman scattering microscopy

et al. 2013

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“…[22][23][24] The technique has seen routine use in recent decades in the pharmaceutical industry for investigation of composition heterogeneity in tablets and polymorph screening of excipients. [25][26][27] However, except for a recent feasibility study from this laboratory, [28] the Raman technique has not been exploited in the characterization of amorphous phase behavior in freeze-dried systems. Additionally, to our knowledge, there are no studies investigating the use of this technique for the investigation of amorphous phase separation during the freezing process.…”

Section: Introductionmentioning

confidence: 99%

The Study of Amorphous Phase Separation in a Model Polymer Phase-Separating System Using Raman Microscopy and a Low-Temperature Stage: Effect of Cooling Rate and Nucleation Temperature

Padilla

Chou

Luthra

et al. 2011

Journal of Pharmaceutical Sciences

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“…4. We note that diprophylline and mannitol are known to exhibit variations in their vibrational spectra as functions of crystal orientation [31,32], and we have selected a region of the sample to image that contains few of these variations.…”

mentioning

confidence: 99%

Epi-detection of vibrational phase contrast coherent anti-Stokes Raman scattering

et al. 2014

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We demonstrate a system for the phase-resolved epi-detection of coherent anti-Stokes Raman scattering (CARS) signals in highly scattering and/or thick samples. With this setup, we measure the complex vibrational responses of multiple components in a thick, highly-scattering pharmaceutical tablet in real time and verify that the epi-and forward-detected information are in very good agreement. Coherent anti-Stokes Raman scattering (CARS) has matured in recent years into an imaging and spectroscopy technique that is finding applications in a range of disciplines including biology [1][2][3][4], remote sensing [5,6], and pharmaceutics [7,8]. The high spatial and spectral resolutions of CARS, combined with its capabilities for imaging in both transmission and reflection [9,10] at speeds up to video rate [11], have led to work specifically aimed at bringing down costs and complexity [12] to enable its use by non-specialists. However, this technique is not without problems. In particular, a strong, frequencyindependent non-resonant background interferes with the resonant signal of interest, reducing contrast and creating imaging and spectral artifacts that can be difficult to interpret. In order to remove, suppress, or extract this non-resonant background, a number of specialized methods have been developed that exploit polarization [9,13,14], spectral [15], time [16][17][18], and/or phase [19][20][21] dependencies of the CARS process. This last feature is of particular interest because it can be used to determine the full complex vibrational response of an arbitrary sample [22]. We previously introduced a method known as vibrational phase contrast CARS (VPC-CARS) to measure the pure vibrational phase of a sample [23], and used it to measure the full vibrational responses of multiple materials in both heterogeneous and homogeneous mixtures [24]. Heterodyne CARS measurements, in which an external local oscillator is interfered with the CARS emission, contain information about both the vibrational phase of the molecular oscillators and the relative local phases of the optical excitation fields. The local excitation phase is subject to disturbances from the variations in the relative phases of the pump, Stokes, and local oscillator beams, which can come from refractive index differences in the sample, interferometric instabilities, and field-of-view curvature resulting from dispersion in the focusing objective lens. To remove these effects a separate measurement is made in which only the local excitation phase is detected. The difference of the heterodyne and local excitation phases is the pure vibrational phase of the molecular oscillators. In previous experiments, heterodyne and local excitation phase measurements were performed in series on a pixel-by-pixel basis, with the local oscillator at nanowatt levels for the heterodyne process and at multi-millwatt powers for the local excitation phase detection. The exact power of the heterodyne local oscillator was a critical parameter for obtaining shot-noise-limited measurem...

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Investigation into the subambient behavior of aqueous mannitol solutions using temperature-controlled Raman microscopy

Cited by 19 publications

References 25 publications

In plantaimaging of Δ9-tetrahydrocannabinolic acid inCannabis sativa L.with hyperspectral coherent anti-Stokes Raman scattering microscopy

In plantaimaging of Δ9-tetrahydrocannabinolic acid inCannabis sativa L.with hyperspectral coherent anti-Stokes Raman scattering microscopy

The Study of Amorphous Phase Separation in a Model Polymer Phase-Separating System Using Raman Microscopy and a Low-Temperature Stage: Effect of Cooling Rate and Nucleation Temperature

Epi-detection of vibrational phase contrast coherent anti-Stokes Raman scattering

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