The present invention relates to particulate compositions comprising at least 50% of dioleoyl phosphatidyl ethanolamine (DOPE) and 1 to 50% of Polysorbate 80 (P80). All parts are by weight relative to the sum of the weights of a+b and the compositions comprise non-lamellar particles or form non-lamellar particles when contacted with an aqueous fluid. The compositions have advantageous stability and low toxicity and the invention also relates to pharmaceutical compositions thereof.