Stability indicating assay

In this article forced degradation is a degradation of drug product and new drug substance at different condition more severe accelerated condition. The forced degradation studies ensure chemical behavior of the molecule which in turn helps the development of formulation and packaging. The HPLC is an essential analytical tool in assessing drug and product stability. It insists various conditions like humidity, temperature, light and environmental factors which may affects the drug substance and drug product.

Amitriptyline and chlordiazepoxide in bulk and formulation were estimated by stability indicating reverse phase high performance liquid chromatographic method. For the proposed method the chromatographic conditions are C18 column (250mm×4.6mm i.d., 5µ particle size), mobile phase was mixture of acetonitrile and triethylamine buffer pH 2.5 at a ratio of 30:70. The injection volume was 20µl with a flow rate 1.0ml/min at a ambient temperature. The wave length selected was 220nm and retention times were found to be 4.55 and 5.893mins for amitriptyline and chlordiazepoxide respectively. Amitriptyline shows linear curve at a concentration range of 5-20µg/ml and for chlordiazepoxide the linearity was obtained for the concentration range of 1.8-6.4µg/ml and regression coefficient was found to be 0.997 and 0.999 for amitriptyline and chlordiazepoxide. The limit of detection  and limit of quantification for amitriptyline was found to be 0.02µg/ml and 0.05µg/ml and for chlordiazepoxide was found to be 0.01µg/ml and 0.03µg/m. amitriptyline and chlordiazepoxide shows recoveries were ranged  from 99.98% – 100.08 % and 99.96%- 100%respectively. The method was performed based on ICH guidelines. In the detection of these drugs degradation products were not interfered and the method was considered as new stability indicating method.