HPLC with Diode-Array Detection for Determination of Leflunomide in Tablets

We have developed and validated a simple HPLC method for analysis of leflunomide in tablets. Method conditions were determined by assay of a photodegraded sample of leflunomide. Optimum chromatographic performance was obtained with a C18 column and acetonitrile-water as mobile phase. Comparison of spectra recorded with a diode-array detector during elution of the leflunomide peak enabled determination of method specificity. The method is highly sensitive (detection limit 10 ng mL−1) and robust to deliberate variation of the conditions (RSD of peak area < 2.0%). Precision and accuracy were adequate over the concentration range 10 to 100 µg mL−1. These results show the proposed method is suitable for its intended use.