The present invention relates to parenteral formulations for certain long chain saturated and monounsaturated fatty acid derivatives of 2,2-difluorodeoxycytidine (Gemcitabine). In particular, the present invention relates to a parenteral pharmaceutical composition and a method of the preparation thereof, in order to accommodate therapeutically effective doses of the said derivatives ameliorating compliance in the treatment of cancer. The composition has an average particle size in the range of 2.5-30 nm and typically contains a phospholipid. A preferred active ingredient is gemcitabine-5-elaidic acid ester.