Characterization of doxorubicin liposomal formulations for size-based distribution of drug and excipients using asymmetric-flow field-flow fractionation (AF4) and liquid chromatography-mass spectrometry (LC-MS)

Doxorubicin liposomal formulations were characterized for the particle size distribution and size-based distribution of lipids and doxorubicin (DOX). An asymmetric flow-field flow fractionation (AF4) method was developed and employed for size-based fractionation of the doxorubicin liposomal formulations. Liposome size-fractions collected from AF4 were analyzed for particle size using nanoparticle tracking analysis (NTA) and dynamic light scattering (DLS). Three doxorubicin liposomal formulations (DLFs) were compared for liposome size distributions. We did not observe any statistically significant variation in D10, D50 and D90 value of size distributions of three fomulations. Lipids and DOX compositions in liposomal fractions from AF4 were determined using liquid chromatography-mass spectrometry (LC-MS) method. The lipid compositions are close to be constant as a function of liposomal size. The drug to lipid ratio was close to be constant for all the size fractions suggesting drug loading may be proportional to membrane surface area of liposomes as membrane surface area is proportional to the amount of lipid in a given liposome. This analytical method could be used in liposomal based drug development as a tool for comparison of generic versions against the reference standard drug.