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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.

No MeSH data available.


(a) CT images showing coronal CT slices, a reconstructed maximum intensity projection, and 3D volume rendering of the Aspirin tablets coated with the iron wax composite, embedded in 2% agar. Addition of Iohexol or BaSO4 improved CT visibility. Post-release images showed the degradation of the coating completely and the partial dissolution of the aspirin template. (b) Quantification of radiopacity of aspirin tablet with iron wax coating, and aspirin table incorporating 25% w/w BaSO4 or 10% w/w Iohexol. Error bars represent the standard deviation in Hounsfield units of all pixels in the 3D region of interest shown segmented in the 3D volume render image in (a).
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f7: (a) CT images showing coronal CT slices, a reconstructed maximum intensity projection, and 3D volume rendering of the Aspirin tablets coated with the iron wax composite, embedded in 2% agar. Addition of Iohexol or BaSO4 improved CT visibility. Post-release images showed the degradation of the coating completely and the partial dissolution of the aspirin template. (b) Quantification of radiopacity of aspirin tablet with iron wax coating, and aspirin table incorporating 25% w/w BaSO4 or 10% w/w Iohexol. Error bars represent the standard deviation in Hounsfield units of all pixels in the 3D region of interest shown segmented in the 3D volume render image in (a).

Mentions: The preceding capsule designs used in Figs 3_6 have relied on a gelatin capsule template that is filled with the drug of interest and contrast agent, prior to coating with the waterproof iron-wax composite. However, to simplify the design of the system, a gelatin capsule-free approach was investigated, in which the drug and contrast agent were compacted into a solid tablet, then coated directly in the iron-wax composite. Using this approach, we successfully incorporated BaSO4 and Iohexol into a commercial aspirin formulation at 25 and 10% w/w respectively. CT images showed that these tablets also appeared bright on CT images (Fig. 7), again with much higher radiopacity than bone.


Magnetic hyperthermia controlled drug release in the GI tract: solving the problem of detection
(a) CT images showing coronal CT slices, a reconstructed maximum intensity projection, and 3D volume rendering of the Aspirin tablets coated with the iron wax composite, embedded in 2% agar. Addition of Iohexol or BaSO4 improved CT visibility. Post-release images showed the degradation of the coating completely and the partial dissolution of the aspirin template. (b) Quantification of radiopacity of aspirin tablet with iron wax coating, and aspirin table incorporating 25% w/w BaSO4 or 10% w/w Iohexol. Error bars represent the standard deviation in Hounsfield units of all pixels in the 3D region of interest shown segmented in the 3D volume render image in (a).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f7: (a) CT images showing coronal CT slices, a reconstructed maximum intensity projection, and 3D volume rendering of the Aspirin tablets coated with the iron wax composite, embedded in 2% agar. Addition of Iohexol or BaSO4 improved CT visibility. Post-release images showed the degradation of the coating completely and the partial dissolution of the aspirin template. (b) Quantification of radiopacity of aspirin tablet with iron wax coating, and aspirin table incorporating 25% w/w BaSO4 or 10% w/w Iohexol. Error bars represent the standard deviation in Hounsfield units of all pixels in the 3D region of interest shown segmented in the 3D volume render image in (a).
Mentions: The preceding capsule designs used in Figs 3_6 have relied on a gelatin capsule template that is filled with the drug of interest and contrast agent, prior to coating with the waterproof iron-wax composite. However, to simplify the design of the system, a gelatin capsule-free approach was investigated, in which the drug and contrast agent were compacted into a solid tablet, then coated directly in the iron-wax composite. Using this approach, we successfully incorporated BaSO4 and Iohexol into a commercial aspirin formulation at 25 and 10% w/w respectively. CT images showed that these tablets also appeared bright on CT images (Fig. 7), again with much higher radiopacity than bone.

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.

No MeSH data available.