Analysis of gemcitabine liposome injection by HPLC with evaporative light scattering detection

Gemcitabine liposome injection (i.e., stealth liposomes) has facilitated the targeting of gemcitabine for cancer treatment. We systemically reviewed liposome-based drug-delivery systems, which can improve pharmacokinetics, reduce side effects, and potentially increase tumor uptake, for pancreatic cancer therapy. A novel liposomal formulation, which allows for higher tumor-targeting efficiencies and can be used in current clinical trials to treat this challenging disease, has gained great popularity and attention. In this work, a simple, rapid high-performance liquid chromatography (HPLC) method was developed for the simultaneous determination of N-(carbonyl-methoxypolyethylene glycol 2000)-1, 2-distearoyl-sn-glycero-3-phosphoethanolamine sodium salt and neutral colipids cholesterol and hydrogenated soy phosphatidylcholine or distearoyl phosphatidylcholine. Because of the poor ultraviolet absorbance of the lipids, evaporative light-scattering detection (ELSD) was used to monitor the separation. The separation was carried out on a YMC-Pack column (YMC Co., Ltd., Kyoto, Japan). Lipids were eluted using binary linear gradients starting from a mixture of 80% A and 20% B to 100% B in 10 minutes, followed by a 6-minute plateau at 100% B, where A is chloroform/isopropyl alcohol/diethylamine/trifluoroacetic acid (TFA) (50:50:0.01:0.0025) and B is chloroform/isopropyl alcohol/H₂O/diethylamine/TFA (41:50:9:0.01:0.0025). The mobile phase composition was then changed back to initial solvent mixture in 1 minute, and the column was equilibrated for 13 minutes before every subsequent run. Then, 0.025% (v/v) TFA was added into the mobile phase to enhance the retaining of the stealth lipids. This newly developed method enabled direct analysis of liposomes without solvent lipid extraction and was validated to be linear, precise, accurate, specific, and sensitive. The method has been successfully employed in a wide range of lipid-based formulation screening, process development, and stability testing. Further, we describe the simple, rapid HPLC-ELSD method for the simultaneous determination of all the lipids and active pharmaceutical ingredients in various liposome-based drug formulations. The method can quantitate all the lipids of active targeting liposomes, which bond with folic acid.