Characterization of Polymorphs of a Novel Quinolinone Derivative, TA-270 (4-Hydroxy-1-methyl-3-octyloxy-7-sinapinoylamino-2(1H)-quinolinone)

The polymorphic forms and amorphous form of TA-270 (4-hydroxy-1-methyl-3-octyloxy-7-sinapinoylamino-2(1H)-quinolinone), a newly developed antiallergenic compound, were characterized by powder X-ray diffractometry, thermal analysis, infrared spectroscopy and solid state 13C-NMR. The intrinsic dissolution rates of polymorphic forms were measured using the rotating disk method at 37 °C. The dissolution rates correlated well with the thermodynamic stability of each polymorphic form. These dissolution properties were clearly reflected in the oral bioavailability of TA-270 in rats. The transition behavior for each polymorph and for the amorphous form was studied under the high temperature and humidity conditions. The β- and δ-forms were transformed into the α-form by heating. The amorphous form was also easily crystallized into α-form by heating, however it was relatively stable under humidified conditions. The internal molecular packing of each polymorph was estimated from IR and solid state NMR spectral analysis.