Lactide–glycolide (LG) polymers have emerged as critical biodegradable and biocompatible materials widely utilized in advanced pharmaceutical and biomedical applications, particularly in controlled and long-acting drug delivery systems. Their global adoption reflects increasing regulatory emphasis on safety, efficacy, and reproducibility in complex drug formulations. This study focuses on the comprehensive characterization of LG polymer used in the reference listed drug (RLD), Lupron Depot, highlighting its significance in achieving regulatory equivalence and facilitating generic drug development.

A robust analytical framework incorporating advanced techniques such as nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), infrared spectroscopy (IR), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) was employed to evaluate key physicochemical attributes. These include monomer composition, molecular weight distribution, polymer architecture, end-group functionality, and thermal behavior—parameters essential for ensuring consistency with regulatory standards and product performance.

The results confirm that the extracted LG polymer closely aligns with a standard copolymer exhibiting a lactide:glycolide ratio of 75:25, a molecular weight of approximately 14,000 Da, and an acid end group. Such alignment underscores the importance of precise polymer characterization in meeting global regulatory requirements for qualitative (Q1), quantitative (Q2), and performance (Q3) equivalence in complex injectable drug products.

Overall, this study reinforces the role of harmonized analytical methodologies and pharmacopeial standards in supporting global scientific recognition, regulatory compliance, and the development of high-quality generic formulations. It highlights the critical contribution of standardized characterization approaches in bridging innovation with regulatory alignment across international pharmaceutical markets.