Significance and Use
5.1 The growing interest in liposomal formulations in the pharmaceutical industry requires QC and thorough characterization and quantification of lipids that form liposomes (6). Lipid composition has proven to be a critical attribute of the liposomal formulation; it directly influences the stability of the formulation, drug loading, performance, size, and surface characteristics of the liposome. Cholesterol plays a key role in controlled drug release by adding stability to the liposome (7). Significant variation in the lipid composition and ratio of the components will influence the safety, biodistribution, drug efficacy, and drug release kinetics of the liposomal formulation (8-11).
5.2 This test method is a fast and reliable procedure for the quantification of cholesterol, DSPE-PEG 2000, and HSPC in liposomal formulations using HPLC-CAD.
5.3 This test method can be used for QC and QA and to ascertain variations in component profiling of liposomal formulations.
Scope
1.1 This test method is for the separation of lipids in liposomal formulations through high performance liquid chromatography (HPLC) and their quantitation using a mass-flow sensitive charged aerosol detector (CAD).
1.2 This test method is specifically for liposomal formulations containing cholesterol, 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DSPE-PEG 2000) and hydrogenated soy L-α-phosphatidylcholine (HSPC).
1.3 This test method is applicable to report the absolute concentrations and ratio of cholesterol, DSPE-PEG 2000, and HSPC in liposomal formulations. Assessment of the stability of the analytes in terms of their degradation profiles as a result of oxidation or hydrolysis is beyond the scope of this test method.
1.4 This test method includes calibration standards preparation, sample preparation, method validation, and sample analysis. This method also contains specifications for instrumentation and the chromatography experimental procedure.
1.5 The detection limit and quantitation limit for the analytes in this test method is in the range of 0.1–2.0 µg/g and 1.0–5.0 μg/g respectively. The analytical measurement range for cholesterol, DSPE-PEG 2000, and HSPC is 5–300 µg/g.
1.6 All observed and calculated values shall conform to the guidelines for significant digits and rounding as established in Practice D6026.
1.7 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.
1.8 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.
1.9 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.
