Glass transition dynamics of enantiomer (+)-ibuprofen

Acoustic and thermal anomalies in a liquid–glass transition of racemic S(+)–R(−) ketoprofen

“…The smaller value of water is related to the intermolecular force, such as formation of hydrogen bonded tetrahedral network of water molecules. In ketoprofen, the value of β is slightly larger than that of S-(+)-ibuprofen ( = 6.049 × 10 −4 (K −1 )) [18], so it seems that intermolecular force of ketoprofen is slightly weaker than that of S-(+)-ibuprofen. Figure 5 shows the real and imaginary parts of the complex heat capacity of ketoprofen for some investigated frequencies.…”

“…The frequency shift and the linewidth provide the sound velocity and the acoustic attenuation of acoustic waves thermally excited in a material, respectively. Recently, acoustic properties of pharmaceutical aspirin and ibuprofen in their crystalline, glassy and liquid states were investigated by Brillouin scattering, from which acoustic anomaly across a glass transition was clearly observed [16][17][18]. In addition, Brilloun scattering is sensitive to the existence of intramolecular secondary relaxation which couples with acoustic phonon in a GHz range [19][20][21].…”