Thermal stability of mefruside-polyvinylpyrrolidone solid dispersions.

The stability of mefruside-polyvinylpyrrolidone (PVP) 30 solid dispersions at ratios of mefruside/PVP 30 of 9/1, 7/3, and 5/5 (g/g) after mechanical (tableting) and allothermic stressing (50, 60, and 70°C up to 240 hr) was investigated. Only the 5/5 (g/g) solid dispersion showed no recrystallization of mefruside, whereas a slight increase in crystallinity in the 7/3 (g/g) solid dispersion and a strong increase in the 9/1 (g/g) product were detected. The mechanisms of drug recrystallization in such "high-energy products" are discussed.