A new stability indicating RP-HPLC method for the estimation of flucytosine in presence of an internal standard

Flucytosine is fungicidal acting against Candida species but not against other common fungi. Flucytosine is structurally related to the cytostatic fluorouracil and to floxuridine. Flucytosine is chemically 6-amino-5-fluoro-1H-pyrimidin-2-one with molecular formula C4H4FN3O and molecular weight 129.09 g/mol. A new RP-HPLC method has been proposed for the quantification of Flucytosine in presence of internal standard Linezolid in pharmaceutical formulations and the method was validated as per ICH guidelines. Mobile phase consisting of a mixture of Tetra butyl ammonium hydrogen sulphate: Methanol (50: 50, v/v) with a flow rate 1 mL/min and UV detection at 254 nm was used for the assay of Flucytosine in presence of internal standard Linezolid. Flucytosine was exposed to different stress conditions such as acidic, alkaline, oxidation and thermal degradation. Linearity was observed over the concentration range 1.0–100 μg/mL with linear regression equation y = 0.0238x-0.0024 (R² = 0.9998). The LOQ was found to be 0.8937 μg/mL and the LOD was found to be 0.2938 μg/mL. The present method can be successfully applied for the pharmaceutical formulations, kinetics study and bioanalytical studies.