Concentrates or proliposomal compositions of poorly water-soluble drugs and compounds, comprising of one or more membrane forming lipids, a membrane stabilizing agent, in a suitable vehicle, and optionally containing a Polyethylene Glycol (PEG)-coupled phospholipid or a mixture thereof and further, optionally containing pharmaceutically acceptable excipients such as antioxidants, buffering agents, acidifying agents etc. are provided, which have superior long term stability. The concentrates of proliposomal compositions instantly form liposomes of the said poorly water-soluble drugs and compounds on rapid injection to a diluting fluid, the liposomal composition so obtained, characterized by a physical stability more than 24 hours, &ge 95% drug encapsulation and having a particle size diameter of less than 100 nm. The liposomal compositions so obtained can further be directly administered to patients in need of treatment of the poorly water-soluble drugs and compounds.