# Radiolabeled 5‑Fluorouracil-Loaded Solid Lipid Nanoparticles: A Potential Platform for Colorectal Cancer Imaging

## TL;DR

Researchers developed radiolabeled 5-fluorouracin-loaded nanoparticles that could be used for imaging colorectal cancer, showing good stability and strong cell association.

## Contribution

The novel contribution is the development of radiolabeled 5-FU-loaded solid lipid nanoparticles for targeted colorectal cancer imaging.

## Key findings

- The nanoparticles had a mean size below 150 nm and high radiolabeling efficiency (>90%).
- The radiolabeled nanoparticles showed strong and sustained cell association with HT-29 colorectal cancer cells.
- The formulations were biocompatible and exhibited hydrophilic characteristics suitable for systemic circulation.

## Abstract

Radiolabeled 5-fluorouracil (5-FU)-loaded solid lipid
nanoparticles
(SLNs) were successfully developed using high shear homogenization
and ultrasonication techniques. The SLNs were characterized for particle
size, polydispersity index, and zeta potential. The formulations exhibited
a mean particle size below 150 nm with narrow size distribution and
negative surface charge, indicating good colloidal stability. The
radiolabeling of SLNs with technetium-99m ([99mTc]­Tc) was
performed using stannous chloride as the reducing agent, achieving
a high radiolabeling efficiency (>90%). The in vitro radiochemical stability of [99mTc]­Tc-5-FU-SLNs was confirmed
in saline, serum, and cell culture medium, where the radiochemical
purity remained above 90% for up to 6 h. Partition coefficient studies
demonstrated that the radiolabeled formulations exhibited hydrophilic
characteristics, supporting their potential for systemic circulation
with reduced nonspecific tissue uptake. Cellular binding studies using
the HT-29 human colorectal adenocarcinoma cell line revealed that
[99mTc]­Tc-5-FU-SLNs demonstrated strong and sustained cell
association over time, significantly higher than free [99mTc]­Tc-5-FU and negative controls. The SLN formulations were found
to be biocompatible, showing no adverse effects on cell morphology
during the incubation period. These findings indicate that radiolabeled
5-FU-loaded SLNs represent a promising platform for potential use
in targeted colorectal cancer imaging, pending further in
vivo validation.