Carboxylated phosphatidic acid esters

The present invention relates to phosphatidic acid esters of aliphatic and cycloaliphatic hydroxylated hydrocarbons substituted with carboxylic functions. These compounds are particularly useful in the fields of drug targeting with liposomes and MRI contrast media for diagnostics. Novel compounds of formula in which Rand Rare phospholipid fatty acid residues and A is an aliphatic and/or cycloaliphatic hydrocarbon chain optionally substituted by hydroxy and/or further carboxylic functions. The novel compounds are useful for making liposomes of enhanced stability and entrapping capacity.