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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.


Process of capsule synthesis and mechanism of drug release.(a) demonstrates a SPION-wax coated drug capsule which, when at the desired point of release, is then irradiated with radiofrequency, heating the SPIONs and melting the wax coating, (b). Water ingress then dissolves the gelatin drug capsule template, (c) before release of the drug payload, (d). In order to prevent wax melting during incorporation into an agar phantom for MRI/CT imaging, a thin layer of pure octacosane (m.p. 57–62 °C) was added via dip-coating, (e). The octacosane-SPION-wax coated capsule was then incorporated into an agar phantom at ~40 °C, (f).
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f1: Process of capsule synthesis and mechanism of drug release.(a) demonstrates a SPION-wax coated drug capsule which, when at the desired point of release, is then irradiated with radiofrequency, heating the SPIONs and melting the wax coating, (b). Water ingress then dissolves the gelatin drug capsule template, (c) before release of the drug payload, (d). In order to prevent wax melting during incorporation into an agar phantom for MRI/CT imaging, a thin layer of pure octacosane (m.p. 57–62 °C) was added via dip-coating, (e). The octacosane-SPION-wax coated capsule was then incorporated into an agar phantom at ~40 °C, (f).

Mentions: We have found in our previous work that the heat generated from the stimulation of superparamagnetic iron oxide nanoparticles (SPIONs) embedded in an hydrocarbon waxy matrix by radiofrequency was sufficient to melt the matrix in air and water rapidly2223. A gelatin drug capsule, loaded with a desired drug payload, was then coated in the nanoparticle-wax composite, forming the drug delivery vehicle (Fig. 1). The observed rapid release on application of an alternating radiofrequency field is highly desirable as the drug payload is released directly to the site of action, without the need of further, molecular or protein-aided targeting.


Magnetic hyperthermia controlled drug release in the GI tract: solving the problem of detection
Process of capsule synthesis and mechanism of drug release.(a) demonstrates a SPION-wax coated drug capsule which, when at the desired point of release, is then irradiated with radiofrequency, heating the SPIONs and melting the wax coating, (b). Water ingress then dissolves the gelatin drug capsule template, (c) before release of the drug payload, (d). In order to prevent wax melting during incorporation into an agar phantom for MRI/CT imaging, a thin layer of pure octacosane (m.p. 57–62 °C) was added via dip-coating, (e). The octacosane-SPION-wax coated capsule was then incorporated into an agar phantom at ~40 °C, (f).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f1: Process of capsule synthesis and mechanism of drug release.(a) demonstrates a SPION-wax coated drug capsule which, when at the desired point of release, is then irradiated with radiofrequency, heating the SPIONs and melting the wax coating, (b). Water ingress then dissolves the gelatin drug capsule template, (c) before release of the drug payload, (d). In order to prevent wax melting during incorporation into an agar phantom for MRI/CT imaging, a thin layer of pure octacosane (m.p. 57–62 °C) was added via dip-coating, (e). The octacosane-SPION-wax coated capsule was then incorporated into an agar phantom at ~40 °C, (f).
Mentions: We have found in our previous work that the heat generated from the stimulation of superparamagnetic iron oxide nanoparticles (SPIONs) embedded in an hydrocarbon waxy matrix by radiofrequency was sufficient to melt the matrix in air and water rapidly2223. A gelatin drug capsule, loaded with a desired drug payload, was then coated in the nanoparticle-wax composite, forming the drug delivery vehicle (Fig. 1). The observed rapid release on application of an alternating radiofrequency field is highly desirable as the drug payload is released directly to the site of action, without the need of further, molecular or protein-aided targeting.

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.