Stabilizing camptothecin pharmaceutical compositions

A storage stabilized liposomal irinotecan composition comprising cholesterol, one or more phospholipids, and irinotecan sucrose octasulfate (SOS) encapsulated in unilamellar liposomes, said composition having:

• (i) an irinotecan:total phospholipids ratio corresponding to a total of 500 grams±10% by weight irinotecan moiety per mol of total phospholipids;
• (ii) a gram-equivalent ratio of from 0.85 to 1.2, as determined by the molar amounts of co-encapsulated irinotecan and sucrose octasulfate according to the formula:
• gram-equivalent ratio=I/(SN), where I is the molar concentration of irinotecan, S is the molar concentration of sucrose octasulfate and N=8;
• (iii) a pH before storage of from about 7.25 to about 7.5 at room temperature;
• and
• wherein, after the first 6 months storage of said composition at a storage temperature of from 2-8° C., there is less than 20 mol % lyso-phosphatidylcholine (“lyso-PC”), relative to the total phospholipids.