Phosphatidyl oligoglycerols

A pharmaceutical composition comprising a liposome and a pharmaceutical drug, said liposome comprising a phospholipid, alkyl phospholipid, or cholesterol, and 1 to 50 mol % of a compound of formula (A):

• or salts thereof;
• wherein R1 and R2 are independently hydrogen or a saturated or unsaturated C8-C24 alkyl or C8-C24 acyl residue, which may be branched or substituted;
• x is a whole number from 1 to 4;
• and
• m is a whole number from 2 to 5;
• wherein the compound of formula (A) is more than 90% uniform with respect to the value of m, provided that when the liposome contains a phospholipid, the phospholipid and the compound of formula (A) contain the same fatty acid residues, and wherein the pharmaceutical drug is entrapped within said liposome, and wherein the pharmaceutical drug is a member selected from the group consistiun of doxorubicin, epirubicin, daunomycin, idarubicin, hexadecylphosphocholine, 1-octadecyl-2-methyl-rac-glycero-3-phosphocholine, a cis-platinum complex, a mitomycin, a cytokine, an anti-mycotic substance, an anti-protozoal, amphotericin B, Taxol, miltefosin, edelfosin, and ilmofosin.