Analysis of active substance and degradation products/impurities in nimesulide tablets by reversed-phase high-performance liquid chromatography
Today, research has largely focused on examining impurities in pharmaceutical compounds and monitoring the stability of drug substances in pharmaceutical formulations in a given time interval. Recently, emphasis has been placed on impurities, especially degradation products and their limits within specifications. Stress testing/accelerated storage conditions testing can assist in the identification of potential degradation products. This type of testing should include effects of temperature and humidity. In this research, stability of nimesulide tablets from five different manufacturers was tested by using accelerated storage conditions, in which samples were stored in a chamber under the following conditions: temperature 40oC ± 2oC and relative humidity 75 % ± 5 %. The content of nimesulide and impurities formed as a consequence of its degradation was observed within precisely defined time intervals (0,3 and 6 months) by using RP-HPLC method. Test results indicate the appropriate stability of nimesulide in all analyzed tablets. Content of nimesulide ranged between 95,38% - 104,45% of the Recovery value, whilst individual and total impurities were within acceptable limits. It is also worth noting appearance of 3 unknown impurities which are detected in all analyzed products after the period of 6 months at the following relative retention times: 1,75, 2,08 and 2,97.