High intensity focused ultrasound hyperthermia for enhanced macromolecular delivery.

Abstract

Mild hyperthermia has been used in combination with polymer therapeutics to further increase delivery to solid tumors and enhance efficacy. An attractive method for generating heat is through non-invasive high intensity focused ultrasound (HIFU). HIFU is often used for ablative therapies and must be adapted to produce uniform mild hyperthermia in a solid tumor. In this work a magnetic resonance imaging guided HIFU (MRgHIFU) controlled feedback system was developed to produce a spatially uniform 43°C heating pattern in a subcutaneous mouse tumor. MRgHIFU was employed to create hyperthermic conditions that enhance macromolecular delivery. Using a mouse model with two subcutaneous tumors, it was demonstrated that MRgHIFU enhanced delivery of both Evans blue dye (EBD) and Gadolinium-chelated N-(2-hydroxypropyl)methacrylamide (HPMA) copolymers. The EBD accumulation in the heated tumors increased by nearly 2-fold compared to unheated tumors. The Gadolinium-chelated HPMA copolymers also showed significant enhancement in accumulation over control as evaluated through MRI T1-mapping measurements. Results show the potential of HIFU-mediated hyperthermia for enhanced delivery of polymer therapeutics.

• Authors: Nick Frazier, Allison Payne, Joshua de Bever, Christopher Dillon, Apoorva Panda, Nithya Subrahmanyam, Hamidreza Ghandehari
• Journal: Journal of controlled release : official journal of the Controlled Release Society (J Control Release) Vol. 241 Pg. 186-193 (11 10 2016) ISSN: 1873-4995 [Electronic] Netherlands
• PMID: 27686583 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2016 Elsevier B.V. All rights reserved.

Chemical References

• Acrylamides
• Macromolecular Substances
• Organometallic Compounds
• Evans Blue
• Gadolinium
• N-(2-hydroxypropyl)methacrylamide

Topics

• Acrylamides (administration & dosage, metabolism)
• Animals
• Drug Delivery Systems (methods)
• Evans Blue (administration & dosage, metabolism)
• Gadolinium (administration & dosage, metabolism)
• High-Intensity Focused Ultrasound Ablation (methods)
• Hyperthermia, Induced (methods)
• Macromolecular Substances (administration & dosage, metabolism)
• Magnetic Resonance Imaging
• Mice, Inbred Strains
• Neoplasms, Experimental (diagnostic imaging, metabolism)
• Organometallic Compounds (administration & dosage, metabolism)
• Xenograft Model Antitumor Assays