Eneli Adaeze, Wang Kaikai, Gan Jingyao, Diwan Rimpy, Lu Ziyi, Yu Minzhi, Ackermann Rose, Shay Brian, Schwendeman Anna
College of Pharmacy and Biointerfaces Institute, University of Michigan, 2800 Plymouth Rd, Ann Arbor, Michigan, 48109, USA.
AAPS J. 2025 Jun 2;27(4):100. doi: 10.1208/s12248-025-01058-1.
Doxil®, a PEGylated liposomal doxorubicin (DOX) hydrochloride suspension, was the first liposome drug product approved by the U.S. Food and Drug Administration (FDA). Although off-patent, limited generic products have been approved due to challenges in achieving bioequivalence compounded by manufacturing complexity. Regulatory agencies require generic drug products to be bioequivalent to the reference listed drug. In this regard, we developed various analytical methods to analyze Doxil® and its generic drug products for multiple attributes, including liposome size distribution, zeta potential, DOX content, lipid content, purity, non-encapsulated doxorubicin, morphology, nanostructure similarity, and quantified in vitro release. Batch-to-batch variation exists across attributes for different formulations. Minor differences in particle size and zeta potential were observed. Cryo-TEM imaging reveals the distinct coffee bean shape and morphology of the Doxil® liposome. SAXS similarity analysis shows a distinct difference in nanostructure for Dr. Reddy's formulation compared to the innovator formulation. Still, it is revealed to be a consequence of liposome uniformity and homogeneity as depicted in cryo-TEM images. Several methods developed in this work can be complementary to provide a more thorough physicochemical analysis for generic evaluation. Size, morphology, and nanostructure evaluated by DLS, cryo-TEM, and SAXS should be readily employed to assess physicochemical similarity. Content, impurity identification, and amount of free non-encapsulated DOX are used to evaluate formulation sameness. The methods developed in this work provide a physicochemical framework for analytical comparison of complex liposomal generics and may support subsequent development efforts to improve generic drug availability for patient populations in need.
多美素（Doxil®）是一种聚乙二醇化脂质体阿霉素（DOX）盐酸盐混悬液，是美国食品药品监督管理局（FDA）批准的首个脂质体药物产品。尽管已过专利期，但由于在实现生物等效性方面存在挑战，加上生产复杂性，获批的仿制药产品有限。监管机构要求仿制药产品与参比上市药品具有生物等效性。在这方面，我们开发了各种分析方法，用于分析多美素及其仿制药产品的多种属性，包括脂质体大小分布、zeta电位、DOX含量、脂质含量、纯度、未包封的阿霉素、形态、纳米结构相似性以及体外释放定量。不同制剂的各属性之间存在批次间差异。观察到粒径和zeta电位存在微小差异。冷冻透射电子显微镜（Cryo-TEM）成像显示多美素脂质体具有独特的咖啡豆形状和形态。小角X射线散射（SAXS）相似性分析表明，与创新制剂相比，瑞迪博士实验室（Dr. Reddy's）的制剂在纳米结构上存在明显差异。不过，正如冷冻透射电子显微镜图像所示，这是脂质体均匀性和同质性的结果。本研究中开发的几种方法可以相互补充以提供更全面的物理化学分析用于仿制药评估。通过动态光散射（DLS）、冷冻透射电子显微镜和小角X射线散射评估的大小形态和纳米结构应易于用于评估物理化学相似性。含量、杂质鉴定和游离未包封DOX的量用于评估制剂的一致性。本研究中开发的方法为复杂脂质体仿制药的分析比较提供了物理化学框架，并可能支持后续开发工作，以提高有需要患者群体的仿制药可及性。
