Improvement and Study for Dissolution Test of Leflunomide Tablets

OBJECTIVE To improve the current method of dissolution test of leflunomide tablets. METHODS After a series of study on the dissolution meidium, rotate speed and samplingtime, the paddle method was used with 0.5% sodium laurysulfate as the dissolution medium at a rotate speed of 75 r·min^-1, dissolution time was 45 min. Then it was determined by HPLC with detection wavelength of 210 nm, calculated dissolution with peak area according to the external standard, finally carried out the methodology validation for the established method. RESULTS The validation result showed that the linear range of leflunomide was 0.57-14.3 μg·mL^-1, Y=72.157X+2.7486, R²=1, The average recovery was 98.7%. The established method can distinguish one company's product form another while the product from the same company have a good uniformity dissolution. CONCLUSION This method can be useful and convenient without using the organic solvent as dissolution medium in the pharmaceutical method, it can be applied to determine dissolution of leflunomide tablets.