Delivery of contrasting agents for magnetic resonance imaging

A method for the treatment of a condition wherein the erythrocytes are localisable by external magnetic force in the vicinity of an area to be treated, said method comprising:

• administering a preparation comprising a plurality of erythrocytes to a subject in need thereof, and thereafter
• exposing said subject to an external magnetic force in the vicinity of the area to be treated,
• wherein the plurality of erythrocytes comprises viable erythrocytes that contain superparamagnetic nanoparticulate iron oxide (SPIO),
• wherein the SPIO is substantially encapsulated within the cytosol of the erythrocytes such the erythrocytes are not recognized by macrophages unless they are at the end of their physiological life,
• wherein the amount of SPIO present in the preparation is sufficient that the preparation is useful as a magnetic resonance imaging contrast agent,
• wherein the erythrocytes that contain superparamagnetic nanoparticulate iron oxide are viable in vivo having a half-life similar to the half-life of native erythrocytes, and
• wherein the SPIO is coated with carboxydextran.

A method of resonance imaging, comprising:

• administering viable erythrocytes that contain superparamagnetic nanoparticulate iron oxide (SPIO) to a subject in need thereof, and thereafter
• subjecting said subject to magnetic resonance imaging,
• wherein the SPIO is substantially encapsulated within the cytosol of the erythrocytes such that the erythrocytes are not recognized by macrophages unless they are at the end of their physiological life,
• wherein the erythrocytes that contain superparamagnetic nanoparticulate iron oxide are viable in vivo having a half-life similar to the half-life of native erythrocytes, and
• wherein the SPIO is coated with carboxydextran.

A method of increasing the resonance imaging resolution of superparamagnetic iron oxide, comprising:

• substantially encapsulating said superparamagnetic iron oxide within the cytosol of the erythrocytes as to produce viable erythrocytes that are not recognizable by macrophages unless they are at the end of their physiological life, and
• resonance imaging said erythrocytes in vivo,
• wherein the erythrocytes that contain superparamagnetic nanoparticulate iron oxide are viable in vivo having a half-life similar to the half-life of native erythrocytes, and
• wherein the SPIO is coated with carboxydextran.

A method for magnetic resonance imaging, said method comprising:

• administering a preparation comprising a plurality of erythrocytes to a subject in need thereof, and thereafter
• subjecting said subject to magnetic resonance imaging,
• wherein the plurality of erythrocytes comprises viable erythrocytes that contain monodispersed superparamagnetic nanoparticulate iron oxide (SPIO),
• wherein the SPIO is substantially encapsulated within the cytosol of the erythrocytes by dialysing a preparation of said erythrocytes against a hypotonic buffer having an osmolarity of between 60 and 120 mOsm,
• wherein the amount of SPIO present in the preparation is sufficient that the preparation is useful as a magnetic resonance imaging contrast agent, and
• wherein the SPIO is coated with carboxydextran.