[Liposome preparation by a reverse-phase evaporation method and freezing-thawing].

A method for preparing liposomes containing Na3Ca-14C-DTPA by means of phase-reverse evaporation and freezing-thawing is described. Freezing-thawing is required for transformation of the system formed after phase-reverse evaporation at a lipid concentration of over 20-30 mg/ml to liposomal suspension. Liposomes thus obtained contain 10-14 microliters aqueous phase per mumol phosphatidylcholine, their diameter varies between 0.2 and 1.5 micron (the mean value 0.45-0.54 micron). Increasing the concentration of lipids, it is possible to include into liposomes up to 70-80% of 14C-DTPA in solution. The method is believed to be fit for preparing the liposomal forms of other drug hydrophilic compounds.