RESUMEN
Objective:To establish the method for determining nimesulide in thermo-sensitive hydrogels and study the stability of the preparation. Methods:An HPLC method was adopted with a Shim-Pack C18-ODS (150 mm × 4. 6 mm,5 μm) column, the mobile phase was composed of menthol-water-acetic acid (65∶35∶0. 8) with the flow rate of 1. 0 ml·min-1 at 30℃, the detection wavelength was at 299 nm, and the injection volume was 10 μl. Results:The separation of nimesulide, impurities and degradation products was good. The linear range of nimesulide was 2. 43-24. 37μg·ml-1(r=0. 999 8), the average recovery was 100. 02%(RSD=1. 12%, n=5). The lowest detectable limit and the lowest quantitation limit was 0. 098μg·ml-1 and 0. 25μg·ml-1, respectively. The stabil-ity results of hard-light exposure, destructive testing and long-term testing showed that the preparation was basically stable at room tem-perature, while under high temperature with hard light, strong basicity, acidicity or oxidation solution, the preparation was unstable. Conclusion:The method is accurate and reliable in the determination and stability study of nimesulide thermo-sensitive hydrogels. The hydrogels should be stored in shady, cool and dark place.