Abstract: Stable liposome composition for delivering a pharmaceutical agent, the composition comprising: (a) a suitable aqueous medium; (b) liposomes formed from a suitable phospholipid; (c) at least one pharmaceutical agent being at least partially encapsulated in the liposomes, and being selected from: (i) a lipophilic amine and a pharmaceutically acceptable acid, wherein the pharmaceutically acceptable acid is selected from an organic or inorganic acid, and (ii) a pharmaceutically acceptable organic acid salt of a lipophilic amine, and optionally a pharmaceutically acceptable organic acid; wherein the quantity of the pharmaceutically acceptable acid present in the composition is such that the pH of the liposome composition is less than or approximately equal to the pKa of the amino group of the pharmaceutically active lipophilic amine.