Development and Validation of RP-HPLC Method for the Identification of Process Related Impurities of Zolmitriptan

The study was focused toward synthesis, characterization and quantification of 3-Ethyl-indole impurity in Zolmitriptan formulations by Reverse Phase High Performance Liquid Chromatography method. The synthesis of a process related impurity of Zolmitriptan was successfully carried out by Fischer indole procedure. The impurity was purified by column chromatography. Characterization was done by I.R, 1H-NMR, 13C-NMR and GC-MS. Based on the spectral data, the structure of impurity was characterized as 3-Ethyl-indole. An efficient isocratic RP-HPLC was developed and validated according to ICH guidelines with respect to specificity, accuracy, linearity and precision. The validated HPLC method was used for detection and quantitation of 3-Ethyl-indole, a process related impurity of Zolmitriptan, from Zolmitriptan tablet formulations. The above method was found to be specific, accurate, precise, rugged and robust and can be used for routine analysis.