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Poly(Alkyl Cyanoacrylate) Nanoparticles for Delivery of Anti-Cancer Drugs
Published in Mansoor M. Amiji, Nanotechnology for Cancer Therapy, 2006
R. S. R. Murthy, L. Harivardhan Reddy
The potential of transarterial permanent embolization with the use of a mixture of cyanoacrylate and lipiodol for treatment of unresectable primary HCC was also assessed by Loewe et al.185 The study included 36 patients with histologically proven HCC who were treated with transarterial embolization of the hepatic arteries. The study indicated that TAE with use of cyanoacrylate and lipiodol for unresectable HCC is a feasible treatment modality. A similar study conducted by Berghammer et al.190 confirmed the safety of the procedure with minimum side effects. Thus, it constitutes a valuable therapeutic option for patients with Okuda stage I and II HCC.
Miscellaneous procedures
Published in A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha, Clark’s Procedures in Diagnostic Imaging: A System-Based Approach, 2020
A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha
Lymphography is the radiographic examination of the lymphatic system following the introduction of an oily based radio-opaque contrast agent (Lipiodol®). Traditionally this was undertaken by direct cannulation of the lymphatic vessels known as pedal lymphangiography. However, the examination has been largely superseded in favour of CT investigation, MR lymphangiography and lymphoscintigraphy. The procedure does however have the advantage of demonstrating the lymphatic vessels to detect structural changes in normal-sized nodes.
Detection and Description of Tissue Disease: Advances in the Use of Nanomedicine for Medical Imaging
Published in Dan Peer, Handbook of Harnessing Biomaterials in Nanomedicine, 2021
Jason L. J. Dearling, Alan B. Packard
Current methods of encapsulating small-molecule, water-soluble, iodinated compounds in the liposome core still leave a significant amount of contrast agent in the bulk formulation medium resulting in uptake of the non-encapsulated material in the kidney shortly after injection. This can confound quantitative studies as it suggests a triphasic clearance of the nanoparticle or a faster initial clearance phase than is actually the case. However, the presence of this excess material in the bulk formulation solution has the advantage of reducing the rate of loss of the contrast agent from the core of the nanoparticle in vitro, which results in a longer shelf life and more consistent imaging results [13]. This problem arises because the rate of loss of the iodinated contrast agent from the liposome core is related to the concentration difference across the lipid bilayer and also to the osmotic pressure difference. This can be avoided by using the iodinated-polymer method where the iodine is covalently bound to the lipid itself, effectively precluding loss of the iodine from the liposome. Another approach to avoiding this problem was discussed by Wei et al. [14] who developed a multilamellar (rather than unilamellar) liposomal construct. This had the advantage of entrapping high concentrations of iodohexol (50 mg/ml) within the liposomal core while reducing the loss of the iodine by diffusion through the bilayer. A further development of this approach was reported by Kweon et al. [15], who used a mixture of water-soluble and oil-based iodinated compounds. The water-soluble material is trapped in the hydrophilic core while the oil-based material is trapped in the hydrophobic bilayer, resulting in a significant increase in radioopacity in the target organ. Encapsulating iopamidol, a water-soluble iodine contrast agent, in liposomes (giving an iodine concentration of 13.8 mg/ml in the formulation) resulted in a relatively small improvement in contrast. However, loading the liposomes with both iopamidol and lipiodol, an iodinated oil, resulted in iodine concentrations as high as 49.2 mg/ml in the combined formulation, and the lipiodol did not disrupt the liposomal structure. A limitation of this approach is that increasing the amount of lipiodol in the liposome resulted in a mixture that was too viscous to produce a liposomal dispersion. This formulation included cholesterol in addition to 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), which increased the rigidity of the liposomal structure, reducing leakage of entrapped iopamidol and increasing its concentration within the liposomes by 1.6-fold. The in vivo performance of these liposomes was encouraging, with an increase of 30 HU, and the material also showed delayed clearance from the circulation. For comparison, iopamidol, which is commonly used as a contrast agent by itself, produces an increase of <7 HU when used at the same iodine concentration.
Biodegradable poly(lactide-co-glycolide) microspheres encapsulating hydrophobic contrast agents for transarterial chemoembolization
Published in Journal of Biomaterials Science, Polymer Edition, 2022
Seong Ik Jeon, Moo Song Kim, Hyung Jun Kim, Young Il Kim, Hwan Jun Jae, Cheol-Hee Ahn
For constructing radiopaque embolic MSs, the most appropriate type of X-ray contrast agent to be loaded should be chosen. Two clinically available contrast agents, Lipiodol and iodixanol, were examined for MS formation. Figure 1A shows a schematic display of a contrast agent-loaded PLGA MS. Lipiodol is composed of iodinated fatty acid ester based on poppyseed oil, which shows hydrophobic and liquid properties under physiological conditions. When Lipiodol was loaded in PLGA MSs, it could not be entrapped entirely within MSs, and a portion of it escaped to the surface. Lipiodol positioned on the surface of the MS resulted in the MSs sticking to each other when they were dispersed in the aqueous phase, thus making it arduous for them to be delivered through the microcatheter (Figure S1). It is considered that Lipiodol cannot be used as a contrast agent for PLGA MS unless it is tightly encapsulated with a core-shell structure [11], which cannot be implemented through a simple emulsion method.