MPI can also be implemented for in vivo drug release monitoring to guide drug

dosing on the desired location. This approach will enable the physicians to track drug

doses along with real-time adjustments of doses in order to keep them within

permissible limit. Basically, the integration of MPI with drug delivery will aid in

visualization and quantitative spatial distribution of drug in the human system. The

similar strategy was adopted by Zhu et al. for the monitoring of doxorubicin drug

release in a murine breast cancer model. For this purpose, doxorubicin, a chemo-

therapy drug, was loaded on core-shell superparamagnetic Fe3O4 nanocluster@ poly

(lactide-co-glycolide acid) (Fe3O4@PLGA) nanocomposite which can be degraded

under mild acidic conditions, thereby releasing the doxorubicin. After the release of

the drug, Fe3O4 core disassembles allowing the quantification of the drug via MPI.

Employment of MNPs aids in significant enhancement of MPI signals as presented

in Fig. 24.3 (Zhu et al. 2019).

MPI has been extensively explored in the blood pool imaging as MPI detects only

the superparamagnetic moiety in the blood and the surrounding tissues which do not

possess MNPs do not contribute any signal in MPI. Thus, MPI generates images that

assist in distinguishing blood and the surrounding tissue. Khandhar et al. developed

a MPI tracer LS-008 based on the coating of polyethylene glycol (PEG) onto the

Fig. 24.3 Schematic representation for drug release using Fe3O4@PLGA and its MPI-based

monitoring in tumor-bearing mice. MPI signal intensity within the tumor gradually increased

with time after injection of drug-loaded Fe3O4@PLGA into mice. (Reproduced with permission

from Zhu et al. (2019))

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