Leflunomide is a leading drug for the treatment of rheumatoid arthritis. The principle aim of this study was to develop and validate an RP-HPLC method for the determination of leflunomide in bulk and pharmaceutical do...Leflunomide is a leading drug for the treatment of rheumatoid arthritis. The principle aim of this study was to develop and validate an RP-HPLC method for the determination of leflunomide in bulk and pharmaceutical dosage form using diclofenac sodium as an internal standard. For this purpose, chromatography was accomplished on a Purospher Start, C18 （5 μm, 12.5 cm×0.46 cm） column at ambient temperature. Methanol ： water （80 ： 20, V/V） solvent system was selected as mobile phase, the pH of which was adjusted to 3.4 by ortho-phosphoric acid and de- livered at a flow rate of 1.2 mLomin-1. Seperation of leflunomide and diclofenac sodium was carried out on a Purospher Start, C18 equipped with a UV-visible detector at 248 nm. The suitability of the method for the quantita- tive determination of the drugs is proven by validation in accordance with the requirements laid down by the Inter- national Conference on Harmonization （ICH） guidelines. The method was accurate （99.55%--100.03%）, specific, linear （R2〉0.999） and precise （intra-day precision 0.023%--0.93% and inter-day precision 0.26%--0.944%） in the range of 0.5--20 μg·mL^-1. The minimum limit of detection and quantification in pharmaceutical formulation were 0.05 and 0.15 μg.mL^-1, respectively. Thus the proposed method is simple, accurate, reproducible and suitable for the routine analysis of leflunomide in pharmaceutical formulations and was applied to study in vitro drug-metal interactions.展开更多
文摘Leflunomide is a leading drug for the treatment of rheumatoid arthritis. The principle aim of this study was to develop and validate an RP-HPLC method for the determination of leflunomide in bulk and pharmaceutical dosage form using diclofenac sodium as an internal standard. For this purpose, chromatography was accomplished on a Purospher Start, C18 （5 μm, 12.5 cm×0.46 cm） column at ambient temperature. Methanol ： water （80 ： 20, V/V） solvent system was selected as mobile phase, the pH of which was adjusted to 3.4 by ortho-phosphoric acid and de- livered at a flow rate of 1.2 mLomin-1. Seperation of leflunomide and diclofenac sodium was carried out on a Purospher Start, C18 equipped with a UV-visible detector at 248 nm. The suitability of the method for the quantita- tive determination of the drugs is proven by validation in accordance with the requirements laid down by the Inter- national Conference on Harmonization （ICH） guidelines. The method was accurate （99.55%--100.03%）, specific, linear （R2〉0.999） and precise （intra-day precision 0.023%--0.93% and inter-day precision 0.26%--0.944%） in the range of 0.5--20 μg·mL^-1. The minimum limit of detection and quantification in pharmaceutical formulation were 0.05 and 0.15 μg.mL^-1, respectively. Thus the proposed method is simple, accurate, reproducible and suitable for the routine analysis of leflunomide in pharmaceutical formulations and was applied to study in vitro drug-metal interactions.
