to an improvement in the loading capacities of DOPC-based liposomes only. Up to 3.6-fold 11 decrease in drug loading was observed after liposome purification, likely due to the loss of 12 adsorbed and loosely entrapped DTX in the SEC column. Our in vitro toxicity results in PC3 13 monolayer showed that non-purified, DTX-loaded DOPC:Chol liposomes were initially (24 h) 14 more potent than the purified ones, due to the fast action of the surface-adsorbed drug. 15However, we hypothesize that over time (48 and 72 h) the purified, DTX-loaded DOPC:Chol 16 liposomes became more toxic due to high intracellular release of encapsulated DTX. Finally, 17 our cytotoxicity results in PC3 spheroids showed the superior activity of DTX-loaded liposomes 18 compared to free DTX, which could overcome the DTX poor tissue penetration, drug 19 resistance, and improve its therapeutic efficacy following systemic administration. 20 21