Wrinkle formation in a polymeric drug coating deposited via initiated chemical vapor deposition

Christian, Paul; Ehmann, Heike; Werzer, Oliver; Coclite, Anna Maria

doi:10.1039/c6sm01919f

Cited by 18 publications

(28 citation statements)

References 38 publications

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“…Intensities are plotted in a pseudo-color representation as a function of the specular ( q z ) and the in-plane component ( q xy ) of the scattering vector. For the sake of clarity and comparability, all intensity data were plotted in square root representation and are reported using the same color scales [55].…”

Section: Methodsmentioning

confidence: 99%

On the transformation of “zincone”-like into porous ZnO thin films from sub-saturated plasma enhanced atomic layer deposition

Perrotta¹,

Pilz²,

Pachmajer³

et al. 2019

Beilstein J. Nanotechnol.

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The synthesis of nanoporous ZnO thin films is achieved through annealing of zinc-alkoxide (“zincone”-like) layers obtained by plasma-enhanced atomic layer deposition (PE-ALD). The zincone-like layers are deposited through sub-saturated PE-ALD adopting diethylzinc and O2 plasma with doses below self-limiting values. Nanoporous ZnO thin films were subsequently obtained by calcination of the zincone-like layers between 100–600 °C. Spectroscopic ellipsometry (SE) and X-ray diffraction (XRD) were adopted in situ during calcination to investigate the removal of carbon impurities, development of controlled porosity, and formation and growth of ZnO crystallites. The layers developed controlled nanoporosity in the range of 1–5%, with pore sizes between 0.27 and 2.00 nm as measured with ellipsometric porosimetry (EP), as a function of the plasma dose and post-annealing temperature. Moreover, the crystallinity and crystallite orientation could be tuned, ranging from a powder-like to a (100) preferential growth in the out-of-plane direction, as measured by synchrotron-radiation grazing incidence XRD. Calcination temperature ranges were identified in which pore formation and subsequent crystal growth occurred, giving insights in the manufacturing of nanoporous ZnO from Zn-based hybrid materials.

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Section: Methodsmentioning

confidence: 99%

On the transformation of “zincone”-like into porous ZnO thin films from sub-saturated plasma enhanced atomic layer deposition

Perrotta¹,

Pilz²,

Pachmajer³

et al. 2019

Beilstein J. Nanotechnol.

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“…While amorphous drug formulations can be desirable in applications where enhanced drug release is favorable, this will often result in additional polymer-drug interactions. For instance, polymeric coatings exhibit strong wrinkling when deposited on amorphous API films while such behavior is absent on crystalline films due to a smaller difference in elastic modulus 30 . Also, polymeric coatings can influence solid state transitions of drug layers, both enhancing or retarding crystallization kinetics depending on the drug-polymer interactions 31 .…”

Section: Introductionmentioning

confidence: 99%

Controlling Indomethacin Release through Vapor-Phase Deposited Hydrogel Films by Adjusting the Cross-linker Density

Christian

Tumphart

Ehmann

et al. 2018

Sci Rep

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Vapor-phase deposited polymer coatings are applied on thin indomethacin films to modify the drug release. Hydrogel-forming co-polymers of 2-hydroxyethyl methacrylate and ethylene glycol dimethacrylate were prepared directly on top of solution cast indomethacin thin films by initiated Chemical Vapor Deposition (iCVD). This technique allows for solvent-free processing under mild conditions, thus minimizing a potential impact on the pharmaceutical. The drug release behavior, among other properties, was evaluated for polymers of different compositions and at different temperatures. The data show that the release kinetics can be tuned by several orders of magnitude as the cross-linker fraction is varied in the polymer coating. While uncoated indomethacin films were fully released within an hour, polymer coatings showed gradual liberation over several hours to days. Additional insight is gained from evaluating the experimental dissolution data in the framework of diffusive transport. The results of this study show that the iCVD technique has some promises for pharmaceutical technology, potentially allowing for tailored release behavior also for other drug systems.

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“…Encapsulation of amorphous drugs has been investigated in details also with iCVD polymers by Christian et al Three different polymer compositions were deposited by iCVD on top of amorphous clotrimazole films to study the stability of the drug solid state: two different stimuli‐responsive polymers, poly(2‐hydroxyethyl methacrylate) [p‐HEMA], hydrogel, and poly‐(methacrylic acid) [p‐MAA], pH‐responsive, and a non‐responsive hydrophobic fluorinated polymer, poly(perfluorodecyl acrylate) [p‐PFDA] . In their study, the authors compare the effect of different polymer chemistries on the stability of the amorphous clotrimazole by means of optical microscopy and X‐ray diffraction (Figure a).…”

Section: Strategies For Drug Encapsulation and Controlled Deliverymentioning

confidence: 90%

“…As afore‐mentioned, such an encapsulating shell often acts then as diffusion membrane in order to have a timed release and/or as protective barrier, which allows the drug release to occur when specific conditions are met (e.g., barrier disintegration at a specific site in the body). Several vapor phase techniques have been employed for the direct encapsulation of drugs or drug loaded media, taking into account the possibility to treat a vast variety of substrates, such as solid surfaces, nanostructured/engineered surfaces, particles, but also on delicate substrates like amorphous drug films or liquid thin films …”

Section: Strategies For Drug Encapsulation and Controlled Deliverymentioning

confidence: 99%

“…Finally, wrinkle formation upon the deposition of the iCVD polymers has been reported in this work, due to differences in elastic behavior of the drug layer and the polymer. An extended study has been reported in a follow‐up work (Figure c) . Such wrinkles are very promising as these might allow the construction of surface layers of significantly larger surface area, which often helps faster drug release.…”

Section: Strategies For Drug Encapsulation and Controlled Deliverymentioning

confidence: 99%

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Strategies for Drug Encapsulation and Controlled Delivery Based on Vapor‐Phase Deposited Thin Films

2017

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Vapor-phase deposition methods allow the synthesis and engineering of organic and inorganic thin films, with high control on the chemical composition, physical properties, and conformality. In this review, the recent applications of vapor-phase deposition methods such as initiated chemical vapor deposition (iCVD), plasma enhanced chemical vapor deposition (PE-CVD), and atomic layer deposition (ALD), for the encapsulation of active pharmaceutical drugs are reported. The strategies and emergent routes for the application of vapor-deposited thin films on the drug controlled release and for the engineering of advanced release nanostructured devices are presented.

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Wrinkle formation in a polymeric drug coating deposited via initiated chemical vapor deposition

Abstract: Polymeric encapsulation by initiated chemical vapor deposition of clotrimazole in an amorphous state results in the formation of surface wrinkles. The characteristic wrinkle length scales vary thereby as a function of the drug layer's thickness.

Cited by 18 publications

References 38 publications

On the transformation of “zincone”-like into porous ZnO thin films from sub-saturated plasma enhanced atomic layer deposition

On the transformation of “zincone”-like into porous ZnO thin films from sub-saturated plasma enhanced atomic layer deposition

Controlling Indomethacin Release through Vapor-Phase Deposited Hydrogel Films by Adjusting the Cross-linker Density

Strategies for Drug Encapsulation and Controlled Delivery Based on Vapor‐Phase Deposited Thin Films

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