The use of liposomes for the preparation of protein-free lipid emulsions models of chylomicron remnants.

Artificial chylomicron remnants were investigated as a new drug carrier system for the targeting of hepatic parenchymal cells. The emulsions presented here are similar in particle size and composition to natural lipoproteins. The preparations contained triolein, phospholipid, cholesterol and cholesteryl oleate. Egg yolk lecithin was either used to form multilamellar or unilamellar liposomes or it was incorporated into a lipid film prior to emulsification. Typically the lipid film contained triolein, cholesterol and cholesteryl oleate. When multilamellar liposomes were used however, cholesterol and cholesteryl oleate were incorporated into the vesicles. The emulsions were prepared by ultrasonication or by means of a microemulsifier. The unilamellar liposomes used with the microemulsifier yielded the best particle distribution, i.e. in the range of 40-60 as determined by quasi-elastic light scattering. The advantage of the method results from the complete emulsification of the components. The particle size remained unchanged during storage, although flocculation was observed. The results show that the synthesis of artificial chylomicron remnants in a microemulsifier is possible and reproducible.