Method of monitoring the release from liposomes of a product of interest using superparamagnetic nanoparticles

A liposome comprising a thermosensitive lipidic membrane encapsulating superparamagnetic nanoparticles the electrostatic surface charge of which is below −20 mV or above +20 mV when measured in an aqueous medium between pH 6 and 8, for use in a method of monitoring the liposome membrane permeabilization and the incidental release of a product of interest, the method comprising:

• a) measuring T2*,
• b) heating the liposome at Tm or above Tm,
• c) measuring T2* after step b),
• d) obtaining the r2* values from the T2* values obtained from step a) and step c),
• e) determining the ratio of r2* before the heating step at Tm or above Tm/r2* after the heating step at Tm or above Tin, a ratio above 1.5 being indicative of the liposome membrane permeabilization and of the incidental release of the product of interest, thereby monitoring the liposome membrane permeabilization.

A liposome comprising a thermosensitive lipidic membrane encapsulating superparamagnetic nanoparticles the electrostatic surface charge of which is below −20 mV or above +20 mV measured in an aqueous medium between pH 6 and 8, for use in a method of monitoring the liposome membrane permeabilization and the incidental release of a product of interest, the method comprising:

• a) measuring T2* and T1,
• b) heating the liposome at Tm or above Tm,
• c) measuring T2* and T1 after step b),
• d) obtaining r2* and r1 values from the T2* and T1 values obtained from steps a) and c),
• e) determining the ratio of r2*/r1 before and after the heating step at Tm or above Tm, a ratio of r2*/r1 before the heating step b) and of r2*/r1 after the heating step b) above 2 being indicative of the liposome membrane permeabilization and of the incidental release of the product of interest, thereby monitoring the liposome membrane permeabilization.