5-Fluorouracil
(5-FU) being a mainstream anticancer drug is under
keen and detailed investigation for prodrugs formulations in order
to minimize the associated side effects. Cocrystallization of 5-FU
is an innovative technique for the synthesis of 5-FU prodrugs to improve
its anticancer effectiveness. The present study is based on the synthesis
of 5-FU supramolecular synthons with four coformers: succinic acid,
cinnamic acid, malic acid, and benzoic acid utilizing acetone as a
solvent. Solid state grinding followed by a slow evaporation solution
method was applied. Colorless clear crystals were obtained in all
the cases. The cocrystal formation was supported with the help of
Fourier transform infrared (FTIR) spectroscopy and powder X-ray diffraction
(PXRD). Through FTIR, the main peaks of interest in the spectrum of
5-FU were N–H (3409.02 cm–1) and carbonyl
group (1647.80 cm–1), which were prominently shifted
in all spectra of the cocrystals demonstrating the replacement as
well as the development of already present interactions with the new
ones. For 5-FU–cinnamic acid cocrystals, the anticipated peaks
were observed at 1673.13 cm–1 (−CO)
and 3566.89 cm–1 (N–H) manifesting a significant
change in comparison to 5-FU. Furthermore, with the help of PXRD characterization,
the representative peak of 5-FU was recorded at 2θ = 28.80°.
The shifting of this specific peak and development of many new ones
in the spectra of cocrystals proved the development of new structural
entities. Finally, the anticancer activity of all cocrystals was evaluated
in comparison to that of API. All cocrystals manifest significantly
greater growth inhibition potential than the main active pharmaceutical
ingredient. 5-FU–Cinnamic acid (3C) was the one that proved
to be the most potent anticancer agent at all four concentrations:
4.82% (12 μg/mL), 34.21% (25 μg/mL), 55.08% (50 μg/mL),
and 67.29% (100 μg/mL). In short, this study proved to be a
true example to enhance the anticancer potential of 5-FU following
fairly easy fabrication requirements of the cocrystallization phenomenon.
After the successful synthesis of these supramolecular synthons and
subsequent enhancement of growth inhibition potential of 5-FU, these
cocrystals can further be evaluated for in vivo trials
and membrane crossing potentials in the future.