Effect of trehalose in low concentration on the binding and transport of porphyrins in liposome-human serum albumin system

The influence of trehalose on the interaction of liposomes with porphyrins and with human serum albumin (HSA) was studied, Small unilamellar liposomes were prepared from 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC) and from DMPC/1,2-dimyristoyl-sn-glycero-3-phosphatidylglycerol (DMPG) 19: 1 w/w% and incorporated with mesoporphyrin IX (MP) or magnesium mesoporphyr in (MgMP). The fluorescence intensity and anisotropy of porphyrins were mea sured within the temperature range of 15-33 degreesC, in the presence and i n the absence of 3 x 10(-2) M trehalose, to study the location of the porph yrins inside the liposomes and their partition between the liposomes and HS A. Based on the presented data and our earlier results (I, Bardos-Nagy, R. Galantai, A.D. Kaposi, J. Fidy, Int. J. Pharm. 175 (1998) 255-267) we concl ude that trehalose - even at this relatively low concentration - interacts with the head groups of the liposomes and that the presence of DMPG enhance s the effect. This effect seems to kinder the binding of HSA to the liposom e surface and influences the location of MgMP within the liposomes. In the case of MP, the porphyrin partition between the liposomes and HSA was affec ted by trehalose, while for MgMP, trehalose changed the structural conditio ns of porphyrin binding to the liposomes. The amount of trehalose used did not have a general trend to modify the association constants of porphyrin d erivatives either to liposomes or to HSA. (C) 2001 Elsevier Science B.V. Al l rights reserved.