In vitro drug release from liposomes

The drug release behavior from free moeixitecan and MLP was evaluated using the dialysis method against PBS (pH =7.4) containing 0.2% Tween 80. Free moeixitecan solutions and MLP solutions were infused into dialysis bags (1 mL solution per bag at an SN38 equivalent concentration of 0.5 mg/mL) and submerged into 50 mL of PBS containing 0.2% Tween 80 (w/v) and maintained at 37°C under 100 rpm shaking for 96 hrs. At pre-determined time intervals, 1 mL of the release media was collected and equal volumes of fresh media were supplemented. After freeze-drying and redissolution with 1.5 mL methanol, the concentration of moeixitecan and SN38 was analyzed by HPLC. Finally, the cumulative amount of drug released into the media at each time point was calculated as the percentage of total released drug to the initial amount of the drug.