Development of systems for targeting the regional lymph nodes for diagnostic imaging: In vivo behaviour of colloidal PEG-coated magnetite nanospheresin the rat following interstitial administration
L. Illum et al., Development of systems for targeting the regional lymph nodes for diagnostic imaging: In vivo behaviour of colloidal PEG-coated magnetite nanospheresin the rat following interstitial administration, PHARM RES, 18(5), 2001, pp. 640-645
Purpose. Nanoparticles can be utilised for targeting drugs to the regional
lymph nodes or as diagnostic agents. The surface modification of magnetite
nanospheres with poly(ethylene glycol) (PEG) has been assessed by in vitro
characterisation and in vivo studies following subcutaneous administration
to the rat.
Methods. Magnetite nanospheres were prepared with a grafted PEG layer using
various PEG lengths from 350 to 1000 Da. Thermogravimetric analysis was ut
ilised to measure the adsorbed amount of PEG. Colloid stability was confirm
ed by measurement of the particle size and electrophoretic mobility. The ki
netics of injection site drainage and lymph node retention were determined
2 hours after subcutaneous administration, for nanospheres coated with PEG
lengths of 350. 550, 750, and 1000 Da, For the 750 PEG coated nanospheres,
the kinetics of distribution was determined over a 18-hour time course.
Results. The distribution of the nanospheres was modified and the lymph nod
e localisation enhanced by altering the surface coverage of PEG on the magn
etic surface.
Conclusions. PEG-coated magnetite nanospherrs with different surface charac
teristics can be utilised to target a diagnostic agent to regional lymph no
des.