Prediction and experimental validation of solid solutions and isopolymorphs of cytosine/5-flucytosine

Abstract

A computational search for polymorphs of cytosine, 5-flucytosine and a 1:1 mixture of the two substances not only rationalised the preferred packing arrangements but also enabled the finding and characterisation of cytosine/5-flucytosine solid solutions. The structures of the new solid forms were determined by combining laboratory powder X-ray diffraction data and computational modelling.