Effects of the equimolarly mixed cationic-nonionic surfactants of didodecyldimethylammonium bromide and polyoxyethylene sorbitan monooleate 80 on serum proteins-spectroscopic study.

Liposomes are a common delivery vehicle for drugs or biologicals, but some common surfactants used as liposome components may cause denaturation and malfunction of serum proteins and cell surface proteins. In this study, we examined the effects of liposome lipid didodecyldimethylammonium bromide (DDAB), nonionic polyoxyethylene sorbitan monooleate 80 (Tween 80), and the equimolar mixture on the properties of serum proteins. Bovine serum albumin was selected as the main model protein, and the effects of the DDAB, Tween 80, and a 1:1 mixture on its spectroscopic behavior were investigated. The effects of surfactants on the five major serum proteins: human serum albumin, apolipoprotein A1, transferrin, fibrinogen and immunoglobulin G were also examined. Finally, the results were verified on human serum. The results indicated that weak interactions exist between human serum proteins and the equimolar mixture of DDAB-Tween 80, significantly different from the strong interactions of DDAB and Tween 80 with proteins. The salient features of cationic-nonionic surfactants enable their use in liposome composition, with improved drug delivery efficiency.