title: Liposome-encapsulated superparamagnetic iron oxide particles as markers in an MRI-guided search for tumor-specific drug carriers.
abstract: Three different types of liposomes containing superparamagnetic iron oxide particles (SPIOs) as the contrast agent were tested for intratumoral enrichment by magnetic resonance imaging (MRI). The liposome-encapsulated SPIOs were investigated in comparison with AMI-227, dextran-coated SPIOs in two different dosages using the CC531 adenocarcinoma in the liver of WAG/RIJ rats as a model. Reduction of the relative signal intensity (SI) in the tumor in T2-weighted MR images was assumed as a measure of the liposome enrichment in the tumor or adjacent tissue. The samples were tested at dosages with isomolar iron content and at dosages producing the same MR relaxivity R2. For reverse phase evaporation vesicles and small unilamellar vesicles behavior differed remarkably according to the applied dosage. A steady, strong reduction in SI, starting immediately after injection and extending up to 48 h, was observed for small unilamellar vesicles sterically stabilized with polyethylene glycol.
authors.affiliation: Department of Radiology, Universitätsklinikum 'Benjamin Franklin', Freie Universität Berlin, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Päuser
authors.forename: R
authors.initials: R
authors.lastname: Reszka
authors.forename: S
authors.initials: S
authors.lastname: Wagner
authors.forename: K J
authors.initials: KJ
authors.lastname: Wolf
authors.forename: H J
authors.initials: HJ
authors.lastname: Buhr
authors.forename: G
authors.initials: G
authors.lastname: Berger
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis* / Q000378:metabolism*; D000818:Animals; D003287:Contrast Media / Q000008:administration & dosage* / Q000493:pharmacokinetics; D003911:Dextrans / Q000008:administration & dosage; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004337:Drug Carriers; D005290:Ferric Compounds / Q000008:administration & dosage* / Q000493:pharmacokinetics; D008081:Liposomes; D008114:Liver Neoplasms, Experimental / Q000175:diagnosis* / Q000378:metabolism*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D051381:Rats; D011919:Rats, Inbred Strains; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D003911:Dextrans; D004337:Drug Carriers; D005290:Ferric Compounds; D008081:Liposomes; C000499:ferric oxide