Biomedical Engineering Reference
In-Depth Information
much higher than that of gemcitabine, mainly because cisplatin (hydrophobic) is
highly soluble in the oil phase and is encapsulated more easily inside nanoparticles
than is gemcitabine (hydrophilic).
In vitro
experiments of drug release and mag-
netic mobility under an external magnetic fi eld showed that these magnetic
poly(ethyl - 2 - cyanoacrylate) ( PECA ) nanoparticles could serve as a highly versatile
magnetic drug carrier, with sustained release behavior and suffi cient magnetic
susceptibility.
Magnetic nanoparticles containing 5 - fl uorouracil ( 5 - FU ) were tested against
HCC induced in nude mice [146]. Following treatment of the mice with the 5-FU-
linked MNPs, the tumor volume was seen to be markedly reduced and the expres-
sion of protein and mRNA of bcl-2 markedly lowered, while the expression of bax
and caspase 3 was signifi cantly increased. Overall, the study results showed that
targeted magnetic nanoparticles containing 5-FU could improve the chemothera-
peutic effect of 5-FU against hepatocellular carcinoma by decreasing expression
of the
bcl- 2
gene, and increasing the expression of
bax
and
caspase 3
genes.
MNPs with poly(
- caprolactone) ( PCL ) nanoparticles linked to an anticancer
drug (gemcitabine) were developed using an emulsion-diffusion method to
increase the effi ciency of drug delivery for cancer treatment [147]. These particles
were injected into nude mice bearing subcutaneous human pancreatic adenocar-
cinoma cells ( HPAC )
in vivo
. The antitumor effect was demonstrated 15-fold
higher dose when compared to free gemcitabine. The study results indicated that
the magnetic PCL nanoparticles could provide a therapeutic benefi t by delivering
drugs effi ciently to magnetically targeted tumor tissues, thus providing safe and
successful antitumor effects, with low toxicity.
ε
6.3.7
Lymph Node - Targeting MNP s
Sentinel node imaging is commonly performed prior to surgery for breast cancer
and melanoma. While current methods are based on radionuclide lymphoscintig-
raphy, MR lymphangiography (MRL) offers the benefi ts of a better spatial resolu-
tion, without the use of ionizing radiation, if specifi city can be developed. For this,
Kobayashi
et al.
studied a series of dendrimer-based MNPs; the G6 Gd dendrimer
provided the lymphatic system and lymph nodes with peak concentrations, at
24-36 min after injection [148]. Based on
ex vivo
concentration phantoms, high
levels of Gd(III) ions were seen to accumulate within lymph nodes (1.7- 4.4 m
M
Gd; 270- 680 ppm Gd), with high target - to - background ratios (
100). The authors
concluded that the PAMAM-G6 Gd dendrimer might represent a potential agent
for the imaging and targeted therapy of sentinel lymph nodes.
>
6.3.8
Other Novel MNP s for Cancer Targeting
Arsenic trioxide (ATO) is a potent drug in the treatment of acute promyelocytic
leukemia (APL), and has been shown to induce differentiation and apoptosis of
