PROPERTIES OF SOLID DISPERSIONS OF NAPROXEN IN VARIOUS POLYETHYLENE GLYCOLS

Solid dispersions of naproxen in polyethylene glycol 4000, 6000, and 2 0000, aimed at improving the drug dissolution characteristics, were pr epared by both the solvent and melting methods, The drug-polymer inter action in the solid state was investigated using differential scanning calorimetry, hot-stage microscopy, fourier-transform infrared spectro scopy, and x-ray diffraction analysis. Interaction in solution was stu died by phase solubility analysis and dissolution experiments. Compute r-aided molecular modeling was used to supplement the results from pha se solubility studies. No important chemical interaction was found bet ween naproxen and polyethylene glycol, either in solution or in the so lid state, apart from the formation of weak drug-polymer hydrogen bond s. The increase of naproxen dissolution rate from its binary systems w ith polyethylene glycol could be attributed to several factors such as improved wettability, local solubilization, and drug particle size re duction. No influence of polymer molecular weight or of the solid disp ersion preparation method on drug dissolution properties was found.