Palmitoyl derivatives of L-cysteine, cysteamine, L-cystine, cystamine and their incorporation into the bilayers of unilamellar liposomes.

The amino groups of the amino acids L-cysteine and L-cystine as well as their biogene amines cysteamine and cystamine were derivatized with palmitoyl residues. The obtained lipophilic R-SH and R-S-S-R components were incorporated into the bilayers of unilamellar liposomes. The resulting liposomes carrying about 2000 functional groups each remained stable and homogeneous during 60 days after incorporation of N-palmitoyl cysteamine and N,N'-dipalmitoyl cystamine. The incorporation of the lipophilic amino acid derivatives, however, destabilized the resulting liposomes. Via the thiol residues of the functionalized liposomes activated molecules can be linked to the liposomal surface by disulfide bonds.