Method For Loading Multiple Agents Into Delivery Vehicles

1 . A method for simultaneously loading at least two agents into the interior of preformed delivery vehicles, which method comprises contacting preformed liposomes with at least a first agent under conditions that effect active loading of said first agent and

simultaneously contacting said preformed liposomes with at least a second agent under conditions that effect passive loading of said second agent.

2 . The method of claim 1 , which further comprises manipulating the loading temperature to determine an optimum temperature for said loading.

3 . The method of claim 1 or 2 , wherein said conditions that effect active loading of the first agent include a pH gradient.

4 . The method of claim 1 or 2 , wherein the conditions that effect active loading of the first agent comprise inclusion of a metal ion in the interior of said preformed delivery vehicles.

5 . The method of claim 4 , wherein said first agent is able to form a complex with a metal ion.

6 . The method of claim 3 , wherein the interior of said preformed delivery vehicles is maintained at a pH wherein said first agent is a charged moiety.

7 . The method of claim 4 wherein the first agent is a quinolone, an anthracycline, and aminoglycoside, an antibiotic, a nitrogen mustard, a camptothecin or a podophyllotoxin.

8 . The method of claim 7 , wherein the first agent is daunorubicin, doxorubicin or irinotecan and the second agent is cytarabine, FUDR or gemcitabine.

9 . The method of any of claims 1 - 8 wherein the delivery vehicles are liposomes.

10 . The method of any of claims 1 - 9 wherein the first and second agents are loaded in a non-antagonistic ratio.

11 . A composition comprising delivery vehicles loaded by the method of any of claims 1 - 9 .