Solid state NMR characterization of zeolite beta based drug formulations containing Ag and sulfadiazine

Shestakova, Pavletta; Martineau, Charlotte; Mavrodinova, V.; Popova, Margarita

doi:10.1039/c5ra15097c

Cited by 14 publications

(7 citation statements)

References 52 publications

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“…The 27 Al spectra in Figure shows HZ25 to have only 4‐coordinated Al species present, but when Mg is added there is a mix of both 4‐ and 6‐coordinated species. The change in the Al species denoted by 27 Al MAS NMR after addition of Mg indicates that the structure of the zeolite has changed and the lattice has been disrupted . 4‐coordinated Al is found within the zeolite framework (Framework Al, FAL), whereas the 6‐coordinated species belong to extra framework Al species (Extra Framework Al, EFAL) .…”

Section: Resultsmentioning

confidence: 99%

Insights into the production of upgraded biofuels using Mg‐loaded mesoporous ZSM‐5 zeolites

et al. 2020

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Bio-oil catalytic upgrading has been performed using mesoporous Mg-loaded ZSM-5. The presence of Mg modifies both textural and acidic properties, which do not only depend on the Mg content (1 and 5 wt. %) but also on the Si/Al ratio of the parent zeolite (25 and 40). Mg impregnation over mesoporous acidic zeolites has been shown to be essential for further deoxygenation of the raw bio-oil. Thus, remarkable deoxygenation rates have been achieved, exceeding 68 % for a 5 wt. % Mgloaded ZSM-5 (Si/Al = 25). For this catalyst, decarboxylation reactions at MgO active sites seem to be predominant, promoting the upgrading of phenols towards the formation of phenolic compounds with lower oxygen content. As in the case of acidic mesoporous ZSM-5, the formation of aromatics for Mgloaded mesoporous ZSM-5 samples could be mainly related to the promotion of decarbonylation reactions of phenolic compounds over Brønsted acidic sites at the external surface. Interestingly, the presence of strong Lewis acidic sites created by the interaction between (Mg 2 + OH À) + species and extra framework alumina jointly with the remaining Brønsted acidic sites at the external surface could enhance the formation of aromatics through cascade reactions involving ketonization and further aldol condensation and dehydration reactions.

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Section: Resultsmentioning

confidence: 99%

Insights into the production of upgraded biofuels using Mg‐loaded mesoporous ZSM‐5 zeolites

et al. 2020

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“…The strong correlation peak detected between the Si(OAl) sites and SD aromatic and NH protons evidences the localization of the drug near the Q 4 structures. A second correlation peak with lower intensity, is observed between the aromatic protons of SD and the signal, corresponding to [Si(1OH) + Si(1Al)] sites, at 103 ppm [ 44 ].…”

Section: 1 H-x Nmrmentioning

confidence: 99%

Solid-State NMR Spectroscopy: A Key Tool to Unravel the Supramolecular Structure of Drug Delivery Systems

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et al. 2021

Molecules

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In the past decades, nanosized drug delivery systems (DDS) have been extensively developed and studied as a promising way to improve the performance of a drug and reduce its undesirable side effects. DDSs are usually very complex supramolecular assemblies made of a core that contains the active substance(s) and ensures a controlled release, which is surrounded by a corona that stabilizes the particles and ensures the delivery to the targeted cells. To optimize the design of engineered DDSs, it is essential to gain a comprehensive understanding of these core–shell assemblies at the atomic level. In this review, we illustrate how solid-state nuclear magnetic resonance (ssNMR) spectroscopy has become an essential tool in DDS design.

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“…In addition, VCM self-association in the aqueous compartments should also contribute to the formation of bulky structures, favoring their loading. Solid state NMR spectroscopy was used to provide further information about the mechanism of the VCM encapsulation since it allows a deep characterization of the structure and interactions between the drug and the polymer carrier at an atomic level [57]. At first, 1 H and 13 C MAS NMR spectra of empty and VCM-loaded PLGA15C NPs were recorded (Figure S2).…”

Section: Drug Loading and Mechanismmentioning

confidence: 99%

Compartmentalized Polymeric Nanoparticles Deliver Vancomycin in a pH-Responsive Manner

et al. 2021

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Vancomycin (VCM) is a last resort antibiotic in the treatment of severe Gram-positive infections. However, its administration is limited by several drawbacks such as: strong pH-dependent charge, tendency to aggregate, low bioavailability, and poor cellular uptake. These drawbacks were circumvented by engineering pH-responsive nanoparticles (NPs) capable to incorporate high VCM payload and deliver it specifically at slightly acidic pH corresponding to infection sites. Taking advantage of peculiar physicochemical properties of VCM, here we show how to incorporate VCM efficiently in biodegradable NPs made of poly(lactic-co-glycolic acid) and polylactic acid (co)polymers. The NPs were prepared by a simple and reproducible method, establishing strong electrostatic interactions between VCM and the (co)polymers’ end groups. VCM payloads reached up to 25 wt%. The drug loading mechanism was investigated by solid state nuclear magnetic resonance spectroscopy. The engineered NPs were characterized by a set of advanced physicochemical methods, which allowed examining their morphology, internal structures, and chemical composition on an individual NP basis. The compartmentalized structure of NPs was evidenced by cryogenic transmission electronic microscopy, whereas the chemical composition of the NPs’ top layers and core was obtained by electron microscopies associated with energy-dispersive X-ray spectroscopy. Noteworthy, atomic force microscopy coupled to infrared spectroscopy allowed mapping the drug location and gave semiquantitative information about the loadings of individual NPs. In addition, the NPs were stable upon storage and did not release the incorporated drug at neutral pH. Interestingly, a slight acidification of the medium induced a rapid VCM release. The compartmentalized NPs could find potential applications for controlled VCM release at an infected site with local acidic pH.

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Solid state NMR characterization of zeolite beta based drug formulations containing Ag and sulfadiazine

Abstract: The paper presents an investigation of structural changes of zeolite carrier, drug–matrix interactions and localization of drug molecules within the zeolite framework in dual drug formulations with antibacterial properties.

Cited by 14 publications

References 52 publications

Insights into the production of upgraded biofuels using Mg‐loaded mesoporous ZSM‐5 zeolites

Insights into the production of upgraded biofuels using Mg‐loaded mesoporous ZSM‐5 zeolites

Solid-State NMR Spectroscopy: A Key Tool to Unravel the Supramolecular Structure of Drug Delivery Systems

Compartmentalized Polymeric Nanoparticles Deliver Vancomycin in a pH-Responsive Manner

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