Cytotoxicity, hemolysis, and acute in vivo toxicity of dendrimers based on melamine, candidate vehicles for drug delivery.

A small library of dendrimers was prepared from a common precursor that is available in 5 g scale in five linear steps at 56% overall yield. The precursor is a generation three dendrimer that displays 48 peripheral sites by incorporating AB4 surface groups. Manipulation of these sites provided six dendrimers that vary in the chemistry of the surface group (amine, guanidine, carboxylate, sulfonate, phosphonate, and PEGylated) that were evaluated for hemolytic potential and cytotoxicity. Cationic dendrimers were found to be more cytotoxic and hemolytic than anionic or PEGylated dendrimers. The PEGylated dendrimer was evaluated for acute toxicity in vivo. No toxicity--neither mortality nor abnormal blood chemistry based on blood urea nitrogen levels or alanine transaminase activity--was observed in doses up to 2.56 g/kg i.p. and 1.28 g/kg i.v.