Stress Degradation Studies and Development of Validated Stability Indicating Method for Assay of Mirtazapine

This study describes the development and validation of stability indicating RP-HPLC method for Mirtazapine, an antidepressant drug. In order to investigate the stability of drug, a stress testing of drug sample by exposing it to variety of forced degradation conditions has been recommended. Mirtazapine was subjected to stress degradation 1 under different conditions recommended by International conference on Harmonization (ICH). The ICH guideline gives parameters to be considered when validating methods, the objective of validation of an analytical procedure is to demonstrate that it is suitable for its intended purpose. Stress testing methods are screening methods to be used to understand the degradation chemistry of a drug and therefore do not need to be validate to the extent of final control methods. The sample so generated was used to develop a stability indicating High Performance liquid Chromatographic method for Mirtazapine. The chromatographic separation of Mirtazapine and its degradation products was done on C18 column. The mobile phase containing mixture of Water and Acetonitrile in ratio 80:20 was found to be most satisfactory at a flow rate of 1mllmin. Detection was carried out using single wavelength detector at 225nm. The retention time under optimized chromatographic condition was found to be 8.43 minutes, with asymmetry of 1.50. A good linear response was observed in the range of 5-25ug/ml. The method showed good recoveries (average 101.37).