EVIDENCE FOR THE PHAGOCYTOSIS OF INTACT OLIGOLAMELLAR LIPOSOMES BY HUMAN KERATINOCYTES INVITRO AND CONSECUTIVE INTRACELLULAR DISINTEGRATION

While there is evidence for the use of liposomes as drug carriers upon topical application to the skin, the underlying mechanisms are far fr om being clear. Therefore human keratinocytes grown in vitro were expo sed to large oligolamellar liposomes. After attachment and invaginatio n these particles can be found unchanged within the cytoplasm both ins ide and outside of lysosomes. If incorporated into lysosomes the struc tural lipids can be disintegrated and spread within the entire phagoly sosome. Gold labeling adds further to the hypothesis of intact uptake of liposomes by the living cells of the human epidermis.