Background:
Solid Lipid Nanoparticles (SLNs) possess unique in vivo features such as high resistivity,
bioavailability, and habitation at the target site. Coating nanoparticles with polymers such as chitosan greatly affects
their pharmacokinetic behavior, stability, tissue uptake, and controlled drug delivery. The aim of this study was to
prepare and evaluate the biodistribution of 99mTc-labeled SLNs and chitosan modified SLNs in mice.
Methods:
99mTc-oxine was prepared and utilized to radiolabel pre-papered SLNs or chitosan coated SLNs. After
purification of radiolabeled SLNs (99mTc-SLNs) and radiolabeled chitosan-coated SLNs (99mTc-Chi-SLNs) using
Amicon filter, they were injected into BALB/c mice to evaluate their biodistribution patterns. In addition, nanoparticles
were characterized using Transmission Electron Microscopy (TEM), Fourier-transform Infrared Spectroscopy
(FTIR), Differential Scanning Calorimetry (DSC), X-ray Powder Diffraction (XRD) and Dynamic Light Scattering
(DLS).
Results:
99mTc-oxine with high radiochemical purity (RCP~100%) and stability (RCP > 97% at 24 h) was used to
provide 99mTc-SLNs and 99mTc-Chi-SLNs with high initial RCP (100%). TEM image and DLS data suggest 99mTc-
SLNs susceptibility to aggregation. To that end, the main portion of 99mTc-SLNs radioactivity accumulates in the
liver and intestines, while 99mTc-Chi-SLNs sequesters in the liver, intestines and kidneys. The blood radioactivity of
99mTc-Chi-SLNs was higher than that of 99mTc-SLNs by 7.5, 3.17 and 3.5 folds at 1, 4 and 8 h post-injection. 99mTc-
Chi-SLNs uptake in the kidneys in comparison with 99mTc-SLNs was higher by 37.48, 5.84 and 11 folds at 1, 4 and
8h.
Conclusion:
The chitosan layer on the surface of 99mTc-Chi-SLNs reduces lipophilicity in comparison with 99mTc-
SLNs. Therefore, 99mTc-Chi-SLNs are less susceptible to aggregation, which leads to their lower liver uptake and
higher kidney uptake and blood concentration.
Solid lipid nanoparticles for nose to brain delivery of donepezil: formulation, optimization by Box–Behnken design, in vitro and in vivo evaluation
