The present invention is related to a lipid composition contained in and/or containing a carrier comprising at least a first lipid component, at least a first helper lipid, and a shielding compound which is optionally removable from the lipid composition under in vivo conditions, whereby the lipid composition containing carrier has an osmolality of about 50 to 600 mosmole/kg, preferably about 250 - 350 mosmole/kg, and more preferably about 280 to 320 mosmole/kg, and/or whereby liposomes formed by the first lipid component and/or one or both of the helper lipid and the shielding compound in the carrier have a particle size of about 20 to 200 nm, preferably about 30 to 100 nm, and more preferably about 40 to 80 nm.
