Organic solvent vapor effects on phase transition of α and β tegafur upon grinding with solvent additives.

Solvent effects on α tegafur (5-fluoro-1-(tetrahydro-2-furyl)uracil) phase transition to β tegafur during grinding with solvent additive, as well as phase transition in samples exposed to 95% relative solvent vapor pressure has been studied in this research. Samples containing 0.5% and 0.1% of β tegafur in α and β tegafur mixture, as well as samples of pure α tegafur were ground with different solvent additives, and conversion degrees depending on the solvent were determined using PXRD method. Samples with α and β tegafur weight fraction of 1:1 were exposed to 95% relative solvent vapor pressure, and phase transition rates were determined. Solubility of α tegafur, solvent sorption and desorption behavior on α and β tegafur have been examined. It was found that the conversion degree of α tegafur to β tegafur mainly depends on solubility of α tegafur in the relevant solvent, and the conversion degree to β tegafur is higher in such solvents, where solubility of α tegafur is higher. The samples ground in a ball mill with solvent additive had a trend of phase transition dynamics from α tegafur to β tegafur similar to the samples exposed to 95% relative solvent vapor pressure.