Absorption Band Profile of the Origin Region of the b Polarized 4000 Å Anthracene Crystal Transition

<div><div>Scattering-mode Scanning Near-Field Optical Microscopy (sSNOM) allows one to obtain absorption spectra in the mid-IR region for samples as small as 20 nm in size. This configuration has made it possible to measure FTIR spectra of the protein complement of membranes. (Amenabar 2013) We now show that mid-IR sSNOM has the sensitivity required to measure spectra of phospholipids in individual bilayers in the spectral range 800 cm<sup>-1</sup>–1400 cm<sup>-1</sup>. We have observed the main absorption bands of the dipalmitoylphosphatidylcholine headgroups in this spectral region above noise level. We have also mapped the phosphate absorption band at 1070 cm<sup>-1</sup> simultaneously with the AFM topography. We have shown that we could achieve sufficient contrast to discriminate between single and multiple phospholipid bilayers and other structures, such as liposomes. This work opens the way to further research that uses nano-IR spectroscopy to describe the biochemistry of cell membranes and model systems.</div></div><div></div>

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CHARGE-TRANSFER COMPLEXES OF NITRODERIVATIVE OF 9,10- PHENANTHRENEQUINONE WITH ANTHRACENE. CRYSTAL AND MOLECULAR STRUCTURE OF THE COMPLEX (1: 1) 2,4,7-TRINITRO-9,10- PHENANTHRENEQUINONE AND ANTHRACENE

Журнал структурной химии ◽

10.26902/jsc_id66742 ◽

2021 ◽

Vol 62 (1) ◽

Keyword(s):

Molecular Structure ◽

Charge Transfer ◽

Crystal And Molecular Structure ◽

Charge Transfer Complexes ◽

Anthracene Crystal

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Crystal Transition and Drug-excipient Compatibility of Clarithromycin in Sustained Release Tablets

Current Pharmaceutical Analysis ◽

10.2174/1573412915666190328234326 ◽

2020 ◽

Vol 16 (7) ◽

pp. 950-959

Author(s):

Yu Li ◽

Xiangwen Kong ◽

Fan Hu

Keyword(s):

Sustained Release ◽

Powder Diffraction ◽

Magnesium Stearate ◽

Influential Factor ◽

High Concentration ◽

Scanning Calorimetry ◽

X Ray ◽

Sustained Release Tablets ◽

Crystal Transition ◽

Excipient Compatibility

Background: Clarithromycin is widely used for infections of helicobacter pylori. Clarithromycin belongs to polymorphic drug. Crystalline state changes of clarithromycin in sustained release tablets were found. Objective: The aim of this study was to find the influential factor of the crystal transition of clarithromycin in preparation process of sustained-release tablets and to investigate the possible interactions between the clarithromycin and pharmaceutical excipients. Methods and Results: The crystal transition of active pharmaceuticals ingredients from form II to form I in portion in clarithromycin sustained release tablets were confirmed by x-ray powder diffraction. The techniques including differential scanning calorimetry and infrared spectroscopy, x-ray powder diffraction were used for assessing the compatibility between clarithromycin and several excipients as magnesium stearate, lactose, sodium carboxymethyl cellulose, polyvinyl-pyrrolidone K-30 and microcrystalline cellulose. All of these methods showed compatibilities between clarithromycin and the selected excipients. Alcohol prescription simulation was also done, which showed incompatibility between clarithromycin and concentration alcohol. Conclusion: It was confirmed that the reason for the incompatibility of clarithromycin with high concentration of alcohol was crystal transition.

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