PHYSICOCHEMICAL STUDIES ON THE PHOSPHOLIPID-BILAYER INCORPORATED SIALOGLYCOLIPID

With the intention of obtaining a novel liposome as a drug carrier abl e to avoid clearance by the reticuloendothelial system (RES), the auth ors synthesized two sialoglycolipids, i.e., anoylamino-3,6-dioxaoctyl) -beta-N-acetylneuraminic acid sodium salt (Sia-t-pa) and oylamino)-3,6 -dioxaoctyl]-beta-N'-acetylneuraminic acid sodium salt (Sia-t-psa) and modified the surface of their liposomal membrane, Sia-t-pa was found to be eluted from the liposomal membrane by serum albumin, whereas Sia -t-psa was not, using the gel filtration method, In order to clarify t he reason why there was such a difference between Sia-t-pa and Sia-t-p sa, we investigated the properties of the phospholipid bilayer-incorpo rated sialoglycolipids physicochemically. The effect of the anchor str ucture of the sialoglycolipids, i.e., single acyl chain (Sia-t-pa) or double acyl chain (Sia-t-psa), on the fluidity and calorimetric proper ties was noticeably different, It was inferred that the effect was att ributable to a difference in the position of the sialoglycolipid incor porated in the bilayer membrane.