PHAGOCYTIC UPTAKE AND CYTOTOXICITY OF SOLID LIPID NANOPARTICLES (SLN)STERICALLY STABILIZED WITH POLOXAMINE-908 AND POLOXAMER-407

Solid lipid nanoparticles (SLN) as alternative intravenous colloidal d rug carriers were produced by high pressure homogenisation of melted L ipids (glyceroblehenate, cetylpalmitate). Their surface was modified b y using hydrophilic poloxamine 908 and poloxamer 407 block-copolymers in order to reduce the phagocytic uptake by the reticuloendothelial sy stem (RES) after i. v. injection. The phagocytosis reducing effect of the polymers was investigated in vitro in cultures of human granulocyt es, uptake was quantified by chemiluminescence. Modification of the SL N with poloxamine 908 and poloxamer 407 reduced the phagocytic uptake to appr. 8-15% compared to the phagocytosis of hydrophobic polystyrene particles. The modified SLN proved more efficient in avoiding phagocy tic uptake than polystyrene particles surface-modified with these bloc kcopolymers (48% and 38%, respectively). Viability determinations reve aled the SLN to be 10 fold less cytotoxic than polylactide nanoparticl es and 100 fold less than butylcyanoacrylate particles.