1.1 本试验方法描述了一种分析技术，用于定量脂质体制剂中经常存在的主要成分的脂质成分。 1.2 该测试方法使用高效液相色谱法（HPLC）分离脂质体制剂中的脂质，并使用蒸发光散射检测法（ELSD）定量各个成分。 1.3 该测试方法定量了脂质体制剂中的三种主要有机成分:胆固醇、1,2-二硬脂酰-sn-甘油-3-磷酸乙醇胺-N-[甲氧基（聚乙二醇）-2000]（DSPE-PEG 2000）和氢化大豆L-α-磷脂酰胆碱（HSPC）。 1.4 该测试方法可以估计脂质体制剂中胆固醇、DSPE-PEG 2000和HSPC的绝对浓度及其比值（DSPE-PEG 2000:HSPC:胆固醇）。 1.5 本试验方法描述了校准标准品和样品的制备、HPLC和ELSD仪器、方法开发和方法验证、样品分析和数据报告。 1.6 本试验方法中分析物（脂质成分）的检测限和定量限在2 μg/g至4μg/g和7 μg/g至10μg/g。胆固醇、DSPE-PEG 2000和HSPC的分析测量范围为10 μg/g至165μg/g，10 μg/g至300μg/g，以及10 μg/g至200μg/g。 1.7 所有报告值的有效位数和四舍五入均按照实践中制定的指南进行 D6026 . 1.8 单位- 以国际单位表示的数值应视为标准。在适当的情况下，本标准中还包括国际单位制以外的c.g.s单位。 1.9 本标准并不旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者有责任在使用前建立适当的安全、健康和环境实践，并确定监管限制的适用性。 1.10 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 =====意义和用途====== 5.1 脂质体制剂中的脂质组成是脂质体合成过程中的一个重要方面，它决定了稳定性、表面特性、药物包封和药物释放能力。胆固醇组分通过增加脂质体的稳定性在药物的控制释放中起着关键作用。脂质成分的微小变化可以显著改变上述参数 ( 15 ) . 5.2 脂质体制剂中脂质成分的变化可能会影响产品的安全性和功效。因此，应确定脂质体的化学成分。 5.3 制药行业和监管机构要求对脂质成分进行质量控制、质量保证、规范、全面表征和定量 ( 16 , 17 ) . 5.4 该测试方法可用于确定各种脂质体制剂的脂质成分谱的变化。然而，该测试方法不打算识别化学降解产物 ( 18 ) . 5.5 分析分析物的稳定性及其因氧化或水解而产生的化学降解曲线超出了本试验方法的范围 ( 18 , 19 ) .

1.1 This test method describes an analytical technique to quantify lipid components that are often present in liposomal formulations as major components. 1.2 This test method uses high performance liquid chromatography (HPLC) to separate lipids in liposomal formulations and evaporative light-scattering detection (ELSD) to quantify the individual components. 1.3 This test method quantifies three major organic components in liposomal formulations: cholesterol, 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DSPE-PEG 2000), and hydrogenated soy L-α-phosphatidylcholine (HSPC). 1.4 This test method can estimate the absolute concentration of cholesterol, DSPE-PEG 2000, and HSPC and their ratio (DSPE-PEG 2000: HSPC: cholesterol) in liposomal formulations. 1.5 This test method describes preparation of calibration standards and samples, HPLC and ELSD instrumentation, method development and method validation, sample analysis, and data reporting. 1.6 The detection limits and quantitation limits for the analytes (lipid components) in this test method are in the range of 2 µg/g to 4 µg/g and 7 µg/g to 10 μg/g, respectively. The analytical measurement ranges for cholesterol, DSPE-PEG 2000, and HSPC are 10 µg/g to 165 µg/g, 10 µg/g to 300 µg/g, and 10 µg/g to 200 µg/g, respectively. 1.7 Significant digits and rounding of all reported values have been performed according to the guidelines as established in Practice D6026 . 1.8 Units— The values stated in SI units are to be regarded as the standard. Where appropriate, c.g.s units in addition to SI units are included in this standard. 1.9 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.10 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 Lipid composition in a liposomal formulation is an important aspect during synthesis of liposomes, which determines stability, surface characteristics, drug encapsulation, and drug release capabilities. The cholesterol component plays a key role in controlled drug release by adding stability to the liposome. A small variation in the lipid composition can significantly alter the parameters mentioned above ( 15 ) . 5.2 Variation in the lipid composition in the liposomal formulation may influence the safety and efficacy of the product. Therefore, chemical composition of the liposomes shall be determined. 5.3 The pharmaceutical industry and regulatory agencies require QC, QA, specifications, thorough characterization, and quantification of lipid components ( 16 , 17 ) . 5.4 This test method can be used to ascertain variations in the lipid component profiling of various liposomal formulations. However, this test method does not intend to identify chemical degradation products ( 18 ) . 5.5 Analyzing the stability of analytes and their chemical degradation profiles as a result of oxidation or hydrolysis is beyond the scope of this test method ( 18 , 19 ) .