Development of a stability-indicating method for evaluation of impurity profile of Atorvastatin film-coated tablets using cyano column based on core-shell technology

This research highlights the specificity of the new stability-indicating method developed to evaluate the impurity profile of Atorvastatin film-coated tablets. The proposed method has the ability to capture any possible changes that may occur during the stability studies over time and under different stress factors, and is selective enough to enable quality control of finished product from different suppliers of active pharmaceutical ingredient (API)/excipients.  Satisfactory critical peak resolution between specified and unspecified impurities was achieved using the fused-core shell technology and extensively endcapped diisopropyl-cyanopropylsilane stationary phase (Halo ES-CN 150 mm × 4.6 mm, 2.7 µm), with a 10 mM ammonium formate buffer pH 3.5 and acetonitrile as mobile phase. A potential worse case impurity profile was assumed by using retained samples combined with the data obtained for samples manufactured with APIs from different suppliers exposed to the forced degradation study. The mass balance for stressed samples demonstrated the stability-indicating capability of the proposed method.