TY - JOUR
T1 - Manganese-based liposomes comparative approaches
AU - Unger, Evan
AU - Fritz, Thomas
AU - Shen, De Kang
AU - Wu, Guanli
PY - 1993/10
Y1 - 1993/10
N2 - RATIONALE AND OBJECTIVES. The purpose of this study was to further develop and compare manganese-based liposomes prepared by two different approaches wherein a manganese ion was entrapped within the internal aqueous space of the vesicles or into the bilayer surface via membrane bound complexes. METHODS. Small unilamellar liposomes (SUVs) were prepared entrapping manganese chloride. Alkylated complexes of manganese were prepared and also incorporated into SUVs. The two different manganese-based liposomes were compared for in-vitro relaxivity, stability, toxicity, and in-vivo imaging in rats with liver tumors. RESULTS. Liposomes entrapping manganese had a concentration-dependent change in relaxivity that was maximal at a several-fold molar excess of phospholipid relative to manganese ion. Liposomes bearing membrane-bound complexes showed relaxivity inversely proportional to vesicle size. In-vivo imaging showed greater and more specific hepatic enhancement with manganese liposomes bearing alkylated complexes than those entrapping manganese ion. CONCLUSIONS. Correlation effects likely explain the increased relaxivity of manganese entrapped in phospholipid vesicles. Greater efficacy, however, is afforded by liposomes bearing alkylated complexes.
AB - RATIONALE AND OBJECTIVES. The purpose of this study was to further develop and compare manganese-based liposomes prepared by two different approaches wherein a manganese ion was entrapped within the internal aqueous space of the vesicles or into the bilayer surface via membrane bound complexes. METHODS. Small unilamellar liposomes (SUVs) were prepared entrapping manganese chloride. Alkylated complexes of manganese were prepared and also incorporated into SUVs. The two different manganese-based liposomes were compared for in-vitro relaxivity, stability, toxicity, and in-vivo imaging in rats with liver tumors. RESULTS. Liposomes entrapping manganese had a concentration-dependent change in relaxivity that was maximal at a several-fold molar excess of phospholipid relative to manganese ion. Liposomes bearing membrane-bound complexes showed relaxivity inversely proportional to vesicle size. In-vivo imaging showed greater and more specific hepatic enhancement with manganese liposomes bearing alkylated complexes than those entrapping manganese ion. CONCLUSIONS. Correlation effects likely explain the increased relaxivity of manganese entrapped in phospholipid vesicles. Greater efficacy, however, is afforded by liposomes bearing alkylated complexes.
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U2 - 10.1097/00004424-199310000-00014
DO - 10.1097/00004424-199310000-00014
M3 - Article
C2 - 8262748
AN - SCOPUS:0027860371
SN - 0020-9996
VL - 28
SP - 933
EP - 938
JO - Investigative Radiology
JF - Investigative Radiology
IS - 10
ER -