Belinostat
(PXD101), a biopharmaceutical classification system
II (BCSII) drug approved for treating refractory T-cell lymphoma,
is currently administered by intravenous injection. To improve patient
compliance, the development of oral formulations of PXD101 has attracted
attention. Because the solubility and dissolution rate of active pharmaceutical
ingredients can affect the therapeutic effect of the oral formulations,
this work explores solid-state form modification of PXD101 by co-crystallization
with four coformers, namely, theophylline, isonicotinamide (INA),
isoniazid (INH), and l-proline (l-Pro) to solve
the problem of poor water solubility. The four cocrystals were obtained
on the basis of N–H···O, O–H···O,
and O–H···N synthons. All the four obtained
multicomponent crystals were characterized by powder X-ray diffraction
(PXRD) and thermal analysis, meanwhile, crystal structure determination
was performed by single-crystal XRD. The results of CrystalCMP show
the similar packing patterns of PXD101-INA and PXD101-INH cocrystals.
The data analysis from powder dissolution experiments suggested that
the apparent solubility of the obtained multicomponent crystals is
1.14–2.22 times more than that of PXD101, and PXD101-l-Pro shows a completely different dissolution behavior from that
of the other three cocrystals. Finally, 3-(4, 5-dimethylthiazol-2-yl)-2,
5-diphenyltetrazolium bromide (MTT) assay experiments demonstrated
that the PXD101-INA cocrystal can significantly inhibit the proliferation
of Michigan Cancer Foundation-7 (MCF-7) cells even at a low concentration
(0.01 μM). Such results shed light on the potential value of
multicomponent crystals in the further development of pharmaceutical
products.