Identification tests should be specific for the drug substance. Therefore, identification by a single chromatographic retention time alone is not regarded as being specific. However, the use of two chromatographic procedures, where the separation is based on different principles or the use of a combination of tests into a single procedure, such as HPLC/UV diode array, HPLC/MS, or GC/MS is generally acceptable.
For peptide products with a single defined (homogenous) sequence, BioPharmaSpec has developed methods to provide in-depth information for the product and any product-related impurities.
For generics of heterogeneous peptide drug products (i.e. those that vary in amino acid length and sequence, such as glatiramer acetate), the requirement is to demonstrate that the active ingredients in the generic are comparable to the Reference Product. This type of analysis requires high-end analytical characterization and a comparability assessment using statistically significant data.