Development and Validation for the Estimation of Assay and Forced Degradation Impurities of Goserelin Acetate Sustained-Release Implant Using HPLC and LC–MS

Forced degradation studies aim to systemically characterize the degradation products of an active pharmaceutical ingredient (API) and its formulations under harsh conditions that accelerate degradation. These studies are especially valuable for sustained-release products in selecting appropriate packaging materials and storage conditions in the field of pharmaceutics. To demonstrate the degradation pathways and degradation products of the API and products, mass spectrometry is used for further characterization of the degradation products. Goserelin acetate sustained-release implant, which is prepared by hot melt extrusion using biodegradable material polylactic acid-glycolic acid copolymer as a carrier, is used for the treatment of early breast cancer in premenopausal and perimenopausal women. In this study, a simple and sensitive high-performance chromatography method was established following the ICH guidance. We conducted forced degradation experiments to determine the conditions of the product. The forced degradation studies of the goserelin acetate sustained-release implant showed the presence of a single impurity during thermal degradation, as observed in the HPLC analysis. To elucidate the structure of the impurity and characterize its degradation pathway, we performed further characterization using LC–MS.