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Magnetic hyperthermia controlled drug release in the GI tract: solving the problem of detection

View Article: PubMed Central - PubMed

ABSTRACT

Drug delivery to the gastrointestinal (GI) tract is highly challenging due to the harsh environments any drug- delivery vehicle must experience before it releases it’s drug payload. Effective targeted drug delivery systems often rely on external stimuli to effect release, therefore knowing the exact location of the capsule and when to apply an external stimulus is paramount. We present a drug delivery system for the GI tract based on coating standard gelatin drug capsules with a model eicosane- superparamagnetic iron oxide nanoparticle composite coating, which is activated using magnetic hyperthermia as an on-demand release mechanism to heat and melt the coating. We also show that the capsules can be readily detected via rapid X-ray computed tomography (CT) and magnetic resonance imaging (MRI), vital for progressing such a system towards clinical applications. This also offers the opportunity to image the dispersion of the drug payload post release. These imaging techniques also influenced capsule content and design and the delivered dosage form. The ability to easily change design demonstrates the versatility of this system, a vital advantage for modern, patient-specific medicine.

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(a) TEM micrograph of 8.5 nm iron oxide nanoparticles showing polydispersity, with an average core size of about 8.5 nm, (b) SQUID magnetometry measurement showing a saturation magnetisation of 84.7 emu g−1 at 300 K and the absence of hysteretic behaviour indicating superparamagnetism, (c) an XRD pattern of iron oxide nanoparticles (compared with a magnetite standard below) and (d) an average DLS size (by number, 15.3 ± 3.61 nm).
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f2: (a) TEM micrograph of 8.5 nm iron oxide nanoparticles showing polydispersity, with an average core size of about 8.5 nm, (b) SQUID magnetometry measurement showing a saturation magnetisation of 84.7 emu g−1 at 300 K and the absence of hysteretic behaviour indicating superparamagnetism, (c) an XRD pattern of iron oxide nanoparticles (compared with a magnetite standard below) and (d) an average DLS size (by number, 15.3 ± 3.61 nm).

Mentions: TEM analysis of the nanoparticles obtained by co-precipitation demonstrates a polydisperse sample with an average size of 8.5 nm and a standard deviation of 3.6 nm. This is supported by the solvodynamic radius of 15.3 ± 3.61 nm obtained by DLS (Fig. 2d), after washing and re-dispersion in n-hexane. This is a larger value than that obtained for the core size by TEM as this includes the oleic acid ligand corona. High resolution TEM analysis (Figure S2) gave lattice d-spacings of 0.90 nm and 0.248 nm, which are assigned to the <220> and <311> planes of magnetite.


Magnetic hyperthermia controlled drug release in the GI tract: solving the problem of detection
(a) TEM micrograph of 8.5 nm iron oxide nanoparticles showing polydispersity, with an average core size of about 8.5 nm, (b) SQUID magnetometry measurement showing a saturation magnetisation of 84.7 emu g−1 at 300 K and the absence of hysteretic behaviour indicating superparamagnetism, (c) an XRD pattern of iron oxide nanoparticles (compared with a magnetite standard below) and (d) an average DLS size (by number, 15.3 ± 3.61 nm).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5037467&req=5

f2: (a) TEM micrograph of 8.5 nm iron oxide nanoparticles showing polydispersity, with an average core size of about 8.5 nm, (b) SQUID magnetometry measurement showing a saturation magnetisation of 84.7 emu g−1 at 300 K and the absence of hysteretic behaviour indicating superparamagnetism, (c) an XRD pattern of iron oxide nanoparticles (compared with a magnetite standard below) and (d) an average DLS size (by number, 15.3 ± 3.61 nm).
Mentions: TEM analysis of the nanoparticles obtained by co-precipitation demonstrates a polydisperse sample with an average size of 8.5 nm and a standard deviation of 3.6 nm. This is supported by the solvodynamic radius of 15.3 ± 3.61 nm obtained by DLS (Fig. 2d), after washing and re-dispersion in n-hexane. This is a larger value than that obtained for the core size by TEM as this includes the oleic acid ligand corona. High resolution TEM analysis (Figure S2) gave lattice d-spacings of 0.90 nm and 0.248 nm, which are assigned to the <220> and <311> planes of magnetite.

View Article: PubMed Central - PubMed

ABSTRACT

Drug delivery to the gastrointestinal (GI) tract is highly challenging due to the harsh environments any drug- delivery vehicle must experience before it releases it&rsquo;s drug payload. Effective targeted drug delivery systems often rely on external stimuli to effect release, therefore knowing the exact location of the capsule and when to apply an external stimulus is paramount. We present a drug delivery system for the GI tract based on coating standard gelatin drug capsules with a model eicosane- superparamagnetic iron oxide nanoparticle composite coating, which is activated using magnetic hyperthermia as an on-demand release mechanism to heat and melt the coating. We also show that the capsules can be readily detected via rapid X-ray computed tomography (CT) and magnetic resonance imaging (MRI), vital for progressing such a system towards clinical applications. This also offers the opportunity to image the dispersion of the drug payload post release. These imaging techniques also influenced capsule content and design and the delivered dosage form. The ability to easily change design demonstrates the versatility of this system, a vital advantage for modern, patient-specific medicine.

No MeSH data available.


Related in: MedlinePlus