Superparamagnetic Iron Oxide Particles as Marker Substances for Searching Tumor Specific Liposomes with Magnetic Resonance Imaging
Superparamagnetic iron oxide particles (SPIOs) encapsulated with oleic acid were incorporated within the lipid phase of different types of liposomes and served as markers in a search for tumor specific drug-carriers by noninvasive Magnetic Resonance Tomography (MRT). The experiments were performed on the model CC531 adenocarcinoma within the liver of WAG/RIJ rats. The reduction of the relative signal intensity (SI) in the tumor in T’2-weighted MR images was assumed as a measure of the liposome enrichment in the tumor or adjacent tissue. The liposome-encapsulated SPIOs were investigated and compared to AMI-227, dextran-coated SPIOs in two different doses, at isomolar doses regarding their iron content and at isodoses concerning their MR relaxivity R2. Reverse phase evaporation vesicles and small unilamellar vesicles showed a remarkably different behavior depending on the applied dose. A steadily strong SI-reduction, starting immediately after injection and extending up to 48 hours was observed for small unilamellar vesicles sterically stabilized with polyethylene glycol.
KeywordsSuperparamagnetic Iron Oxide Positron Emission Tomography4 Liposome Preparation Relative Signal Intensity Diisopropyl Ether
Unable to display preview. Download preview PDF.
- 3.Gregoriades G (Ed.) (1992). Liposome Technology. CRC Press: Florida.Google Scholar
- 5.van-Leengoed HL, Cuomo V, Versteeg AA et al (1994). In vivo fluorescence and photodynamic activity of zinc phtalocyanine administered in liposomes. British Journal of Cancer 65, 840–845.Google Scholar
- 6.Pouliquen D, Perroud H, Calza F et al (1992). Investigation of the Magnetic Properties of Iron Oxide Nanoparticles Used as Contrast Agents for MRL Magnetic Resonance in Medicine 24, 75–84.Google Scholar
- 7.Weissleder R, Elizondo G, Wittenberg J et al (1990). Ultrasmall superparamagnetic iron oxide: characterization of a new class of contrast agents for MR imaging. Radiology 175, 489–493.Google Scholar
- 8.Bach-Gansmo T, Fahlvik A, Ericsson A et al (1994). Superparamagnetic Iron Oxide for Liver Imaging, Comparison Among Three Different Preparations. Investigative Radiology 29, 339–344.Google Scholar
- 9.Marincek B (1996). Diagnostic improvement in MRI of gynecological neoplasms. Journal Belge Radiology 79 13–17.Google Scholar
- 10.Thomas C, Nijenhus AM, Timens W et al (1993). Liver metastasis model of colon cancer in the rat. Immunhistochemical characterization. Invasion-Metastasis 13, 102–112.Google Scholar
- 12.Chambon C, Clement O, LeBlanche A et al (1993). Superparamagnetic iron oxides as positive MR contrast agents: in vitro and in vivo evidence. Magnetic Resonance Imaging 11, 509–519.Google Scholar
- 13.Hennig J, Nauerth A, Friedburg H (1986). RARE imaging: A fast imaging method for clinical MR. Magnetic Resonance in Medicine 3, 823–833.Google Scholar
- 15.Allen TM (1994). Long-circulating (sterically stabilized) liposomes for targeted Drug delivery. Tips 15, 215–220.Google Scholar