Application of the solid dispersion method to the controlled release of medicine. IX. Difference in the release of flurbiprofen from solid dispersions with poly(ethylene oxide) and hydroxypropylcellulose and the interaction between medicine and polymers

Abstract

Solid dispersions were prepared with a slightly water-soluble flurbiprofen (FP) and water-soluble hydroxypropylcellulose (HPC) or poly(ethylene oxide) (PEO). The release of FP from the FP-HPC and the FP-PEO solid dispersion systems was studied. The state of FP and the interaction between FP and the polymers in the solid dispersions were analyzed by powder X-ray diffractometry, thermal analysis and IR spectrometry. The release rate of FP from the FP-PEO system was significantly larger than that from FP powder and the FP-HPC system that we have previously studied. The dissolution property of the polymer base greatly affected the release of FP from the solid dispersions. In the FP-PEO system, the release rate increased with the increasing percent of PEO. In FT-IR spectra, FP has the carbonyl stretching band at 1703 cm −1 because it is in dimer. The new band was observed at 1736 cm −1 which was attributed to hydrogen bonding between FP and PEO in the FP-PEO system. The peak height ratio (the peak height at 1736 cm −1/the sum of that at 1703 cm −1 and that at 1736 cm −1) was evaluated as the indication of interaction between FP and PEO on the basis of a base-line method. A linear relationship between the peak height ratio and the release rate of FP was observed. These results were probably due to an increase in the ratio of hydrogen bonding of FP with the increasing percent of PEO in the solid dispersion.