CHARACTERIZATION OF A COMMERCIAL LIPOSOME SPRAY

The commercial liposome spray Heparin-pur-ratiopharm(R) was physicoche mically characterized. This preparation is said to result in a fine ge l-film containing pure, concentrated liposomes (including drug) on the skin after application and evaporation of the water/ethanol-mixture o f the system. As phospholipids tends to form lamellar structures at lo wer water concentrations the structural characteristics of Heparin-pur -ratiopharm(R) were investigated in the original preparation and after a drying process, which should be comparable to application on skin. For the characterization several methods were used, e.g. photon correl ation spectroscopy, electron and polarized light microscopy, small ang le X-ray (SAX) scattering and SAX diffraction. The results of the pres ent investigation indicate that there are no changes in the colloidal state of the phospholipids before and after drying and application of the spray. There seem to be only changes in the degree of dispersion o f the liquid crystalline phase, i.e. from small uni- or oligolamellar liposomes in the original preparation via multilamellar vesicles to a lamellar mesophase during the drying process. Therefore, it seems that there are no differences for the application of heparin if a preparat ion containing small uni- or oligolamellar liposomes is used or if the phospholipids are structured differently. The major point of importan ce for drug application, therefore, seems to be the presence of phosph olipids as they possibly work as enhancer for the uptake of the drug t hrough the skin to achieve a quick effect.