Page 10 - ARNM-2-4

Advances in Radiotherapy
& Nuclear Medicine Radionuclide-carrying liposomes

®
®
®
®
®
from the promotion of wound healing to the delivery DepoCyt , Doxil , Lipodox , Myocet , Marqibo ,
of cancer therapies. An example of how drug delivery Vyxeos , Onivyde , Mepact , Ambisome , Arkayce ,
®
®
®
®
®
improves medicine is the use of nanofibers to deliver Inflexal V, Epaxel, DepoDur™, Exparel, and Visudyne .
®
®
treatment to wounds while reducing the chance of bacteria Nine of these drugs are intended for cancer treatment.
7
developing resistance to treatment. This method creates an Since 1992, more than 1000 articles mentioning liposomes
environment around the damaged tissue that promotes cell have been published the National Library of Medicine each
healing. 1,2 year, with over 3,500 articles published in 2023. Liposomes
are capsules composed of a lipid bilayer of phospholipids
The use of nanocapsules for targeted drug delivery first with hydrophilic heads and hydrophobic tails, which allow
became a field of focus for researchers back in the early for encapsulation of various compounds in different parts
1950s. Drug delivery using nanocapsules involves the of the liposome. Compounds that are soluble in water
3
8
encapsulation of a chosen drug or radionuclide in a specific can be carried by the aqueous core of the liposome and
material that can efficiently deliver the therapeutic agent compounds that dissolve in lipids can be carried by the
to a targeted site. Encapsulated drugs can be delivered lipid bilayer as shown in Figure 1.
through a multitude of sites, including gastrointestinal,
oral, rectal, parenteral, subcutaneous, intramuscular, 2. Use of liposomes in radiology
intravenous, intra-arterial, transmucosal, transnasal,
pulmonary, transdermal, and intraosseous anatomic Liposomes can be used to assist in medical imaging based
routes. To achieve the most benefit, the material used on the detection of radionuclides. Using radionuclides for
4
nuclear imaging is fundamental for identifying countless
for encapsulation must be carefully considered, especially
with nanocapsules that carry potentially toxic agents such biological disorders including both cancerous and benign
as chemotherapeutic drugs or radionuclides. tumors, heart disease, and abnormalities in the brain
related to neurodegenerative disorders. Positron emission
The use of liposomes for drug delivery has significantly tomography (PET) and single photon emission computed
increased in the past few decades. Liposomes were first tomography (SPECT) are two imaging modalities used
created in 1961 at the Babraham Institute of the University for the detection of radionuclides within the body. Both
of Cambridge by Alex Bangham. As of February 2023, PET and SPECT are highly regarded for producing a
5
16 drugs using liposomes as drug-carrying capsules have precise location of radionuclides due to their emission of
been approved by the Food and Drug Administration photons, which emit energy that easily penetrate tissue.
(FDA) for clinical use. These drugs include DaunoXome , Detection of radionuclides with these forms of imaging
®
6

Figure 1. Illustration of an encapsulated liposome. Figure created by the authors.

Volume 2 Issue 4 (2024) 2 doi: 10.36922/arnm.4373