Surfactant, but not the size of solid lipid nanoparticles (SLN) influencesviability and cytokine production of macrophages

After intravenous (i.v.) injection, solid lipid nanoparticles (SLN) interac t with mononuclear cells. Murine peritoneal macrophages were incubated with SLN formulations consisting of Dynasan 114 coated with different surfactan ts. The present study was performed to examine the impact of surfactants, w hich are important surface defining components of SLN, on viability and cyt okine production by macrophages. Cytotoxicity, as assessed by the 3-(4,5-di methylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) test, was strong ly influenced by the surfactant used being marked with cetylpyridinium chlo ride- (CPC-) coated SLN at a concentration of 0.001%, and further increased at SLN concentrations of 0.01 and 0.1%. All other SLN formulations - conta ining Poloxamine 908 (P908), Poloxamer 407 (P407), Poloxamer 188 (P188), So lutol HS15 (HS15), Tween 80 (T80), Lipoid S75 (S75), sodium cholate (SC), o r sodium dodecylsulfate (SDS) - when used at the same concentrations reduce d cell viability only slightly. None of the SLN formulations tested induced cytokine production but a concentration-dependent decrease of IL-6 product ion was observed, which appeared to be associated with cytotoxic effects. I L-12 and TNF-alpha were detected neither in supernatants of macrophages tre ated with SLN at any concentration nor in those of untreated cells. In cont rast to the type of surfactant, the size of SLN was found neither to affect cytotoxicity, of SLN nor to result in induction or digression of cytokine production by macrophages. In conclusion, testing the effects of surfactant s on SLN on activity of macrophages is a prerequisite prior to in vivo use of SLN, (C) 2001 Elsevier Science B.V. All rights reserved.