Analysis of flucytosine dosage forms by derivative UV spectroscopy and liquid chromatography.

A simple second-order derivative spectrophotometric method was developed for the selective determination of flucytosine (an antimycotic drug) in the presence of 5-fluorouracil (a cytotoxic agent), its synthetic precursor and degradation product. Traces of 5-fluorouracil in flucytosine were also determined by derivative UV spectroscopy; flucytosine was removed by a selective solid-phase extraction (SPE) procedure using a strong cation-exchange sorbent. The spectrophotometric methods were applied successfully to the quality control of commercial dosage forms of flucytosine and the results were compared with those obtained by a HPLC procedure (cyano column) developed as a reference method.