Anomalous small-angle X-ray scattering study on the spatial distribution of hydrophobic molecules in polymer micelles

Nakanishi, Ryosuke; Machida, Ginpei; Kinoshita, Masaki; Sakurai, Kazuo; Akiba, Isamu

doi:10.1038/pj.2016.32

Cited by 12 publications

(9 citation statements)

References 31 publications

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“…This result means that a part of BrPh filtrates to hydrated shell layer of PEG- b -PtBMA micelles. This result is consistent with the spatial distribution of a phenol derivative incorporated in spherical polymer micelles reported by Sanada et al [ 14 ] and some of our previous studies [ 13 , 17 ]. BrPh can form hydrogen bonds with both PtBMA and PEG.…”

Section: Resultssupporting

confidence: 94%

“…The ASAXS method has been applied for hard materials containing high atomic number elements because the K edges of high atomic number elements are generally located within the energy range of available synchrotron X-ray. Recently, the ASAXS method has also been applied for structural analyses of soft materials, such as micelles and polymer nanoparticles [ 9 , 10 , 11 , 12 , 13 , 14 ]. ASAXS corresponds to the variation of the atomic scattering factor f of a targeted element near its X-ray absorption edge.…”

Section: Introductionmentioning

confidence: 99%

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Elucidation of Spatial Distribution of Hydrophobic Aromatic Compounds Encapsulated in Polymer Micelles by Anomalous Small-Angle X-ray Scattering

et al. 2018

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Spatial distribution of bromobenzene (BrBz) and 4-bromophenol (BrPh) as hydrophobic aromatic compounds incorporated in polymer micelles with vesicular structure consisting of poly(ethylene glycol)-b-poly(tert-butyl methacrylate) (PEG-b-PtBMA) in aqueous solution is investigated by anomalous small-angle X-ray scattering (ASAXS) analyses near Br K edge. Small-angle X-ray scattering (SAXS) intensities from PEG-b-PtBMA micelles containing BrBz and BrPh were decreased as the energy of incident X-ray approached to Br K edge corresponding to the energy dependence of anomalous scattering factor of Br. The analysis for the energy dependence of SAXS profiles from the PEG-b-PtBMA micelles containing BrBz revealed that BrBz molecules were located in hydrophobic layer of PEG-b-PtBMA micelles. On the contrary, it was found by ASAXS that BrPh existed not only in the hydrophobic layer but also in the shell layer. Since ASAXS analysis successfully accomplished to visualize the spatial distribution of hydrophobic molecules in polymer micelles, it should be expected to be a powerful tool for characterization of drug delivery vehicles.

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Section: Resultssupporting

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Elucidation of Spatial Distribution of Hydrophobic Aromatic Compounds Encapsulated in Polymer Micelles by Anomalous Small-Angle X-ray Scattering

et al. 2018

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“…The reason we selected PDMAEMA-b-PMMA is contrast matching between shell of micelle composed of PDMAEMA and solvent. We reported contract matching between PDMAEMA and water, previously [25]. ).…”

Section: Introductionmentioning

confidence: 77%

Spatial distribution of hydrophobic compounds in polymer micelles as explored by anomalous small-angle X-ray scattering near Br K-edge

Nakanishi

Kinoshita

Sasaki

et al. 2016

European Polymer Journal

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“…It can dramatically affect many characteristics, for instance, the extent of solubilization, the drug-loading stability, and the release kinetics of the encapsulated drugs in the delivery systems. 1,2 On the basis of many experimental methodologies, such as UV absorption spectroscopy, 3 nuclear magnetic resonance (NMR), 4 smallangle X-ray 5,6 or neutron scattering, 7 and theoretical considerations, 1 it has been proposed that the hydrophobic core of the micelles serves as a solubilization location of hydrophobic drugs most of the time, and sometimes the palisade region. However, it is noteworthy that all studies described above are focused on the single micellar system composed of a single polymer (PMs), which are not suitable for polymeric mixed micellar systems (PMMs), composed of amphiphilic polymers or polymer surfactants, which can realize functional synergism and higher solubilization capacity, improved stability, and better-controlled drug release performance, superior to the individual component.…”

Section: ■ Introductionmentioning

confidence: 99%

“…In recent years, there has been significant interest in the solubilization region within polymer micelles, which is expected to be of key importance. It can dramatically affect many characteristics, for instance, the extent of solubilization, the drug-loading stability, and the release kinetics of the encapsulated drugs in the delivery systems. , On the basis of many experimental methodologies, such as UV absorption spectroscopy, nuclear magnetic resonance (NMR), small-angle X-ray , or neutron scattering, and theoretical considerations, it has been proposed that the hydrophobic core of the micelles serves as a solubilization location of hydrophobic drugs most of the time, and sometimes the palisade region.…”

Section: Introductionmentioning

confidence: 99%

Understanding the Synergistic Correlation between the Spatial Distribution of Drug-Loaded Mixed Micellar Systems and In Vitro Behavior via Experimental and Computational Approaches

et al. 2021

Mol. Pharmaceutics

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To better promote the application of polymeric mixed micelles (PMMs), a coarse-grained molecular dynamics simulation (CGMD) has been employed to investigate the factors controlling the spatial distribution within the PMMs and predict their drug-loading properties, meanwhile, combined with experimental methods to validate and examine it. In this study, the snapshots obtained from CGMD and the results of proton nuclear magnetic resonance (1H NMR) and transmission electron microscopy (TEM) provide new insights into the distribution principle that the spatial distribution depends on the hydrophobic compatibility of drugs with the regions within PMMs. Docetaxel (DTX) is located within the interior or near the core–corona interface of the HS15 hydrophobic core inside FS/PMMs (PMMs fabricated from a nonionic triblock copolymer (F127)) and a nonionic surfactant (HS15), and therefore, the system with a high HS15 ratio, such as system I, is more suitable for loading DTX. In contrast, the more water-soluble puerarin (PUE) is more likely to be solubilized in the “secondary hydrophobic area,” mainly formed by the hydrophobic part of F127 within FS/PMMs. However, when the initial feeding concentration of the drug is increased or the FS mixing ratios are changed, an inappropriate distribution would occur and hence influence the drug-loading stability. Also, this impact was further elucidated by the calculated parameters (solvent-accessible surface area (SASA), the radius of gyration (R g), and energy landscape), and the analysis of the drug leakage, concluding that inappropriate distribution of the drug would lower the stability of the drug in the PMMs. These results combined together provide new insights into the distribution principle that the spatial distribution of drugs within PMMs depends on the hydrophobic compatibility of drugs with the regions formed by micellar materials. Additionally, in vitro drug release yielded a consistent picture with the above conclusions and provides evidence that both the location of the drug within the systems and the stability of the drug-loading system have a great influence on the drug release behavior. Accordingly, this work demonstrates that we can tune the drug-loading stability and drug release behavior via the drug–PMM interaction and drug location study, and CGMD technology would be a step forward in the search for suitable drug-delivery PMMs.

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Anomalous small-angle X-ray scattering study on the spatial distribution of hydrophobic molecules in polymer micelles

Cited by 12 publications

References 31 publications

Elucidation of Spatial Distribution of Hydrophobic Aromatic Compounds Encapsulated in Polymer Micelles by Anomalous Small-Angle X-ray Scattering

Elucidation of Spatial Distribution of Hydrophobic Aromatic Compounds Encapsulated in Polymer Micelles by Anomalous Small-Angle X-ray Scattering

Spatial distribution of hydrophobic compounds in polymer micelles as explored by anomalous small-angle X-ray scattering near Br K-edge

Understanding the Synergistic Correlation between the Spatial Distribution of Drug-Loaded Mixed Micellar Systems and In Vitro Behavior via Experimental and Computational Approaches

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