PROTEIN-INDUCED CF RELEASE FROM LIPOSOMES IN-VITRO AND ITS CORRELATION WITH THE BLOOD RES BIODISTRIBUTION OF LIPOSOMES/

The kinetics of protein-induced CF release from liposomes of different lipid composition in vitro was studied, including human serum protein s HSA, IgG and HDL. CF release patterns appeared to be similar in the presence or absence of protein in the liposome dispersion medium. The presence of protein merely accelerated CF release in a degree dependen t on liposome composition. The rate of CF release depended on both the liposome composition and the type of protein involved. CF release app eared to be multiphasic. By processing the release data, a 'Destabiliz ation Index' (D.I.) was developed, which is a quantitative expression for the destabilization effect of proteins on liposomes. According to the D.I. values obtained from the different liposome compositions, the destabilization effect of the proteins decreased with an increase in liposome membrane rigidity or with the inclusion of GM(1) or PEG in li posome membrane. With all three proteins, an inverse relationship was found between the % CF released after 1 h liposome-protein incubation in vitro and the BLOOD/RES ratio of the liposomes 2 min after i.v. adm inistration in mice (Panagi et al., 1996). (C) 1998 Elsevier Science B .V. All rights reserved.