Octreotide labeled aggregates containing platinum complexes as nanovectors for drug delivery

The synthesis, formulation and a complete physico-chemical characterization, by dynamic light scattering and small angle neutron scattering techniques, of new liposomal aggregates obtained by co-assembling an amphiphilic molecule containing a platinum complex, Peg1500-Lys(Pt-aminoEtGly)-Lys(C18)2, (abbreviated as (C18)2-PKAG-Pt), with a second amphiphilic monomer,(C18H37)2NCO(CH2)2CO(AdOO)5-Oct ((C18)2L5-Oct), containing the octreotide bioactive peptide, is reported. Liposomes of (C18)2-PKAG-Pt present a radius of 48 nm, whereas the mixed aggregates (C18)2-PKAG-Pt/(C18)2L5-Oct at 90/10M ratio give larger liposomes with a radius of 84 nm. In both cases, the bilayer thickness is ~5.3 nm. Encapsulation of doxorubicin in mixed liposomes is also obtained by using the pH gradient method. The obtained liposomes could represent a new target selective cargo system for delivery of cisplatin based drugs and/or doxorubicin on cells overexpressing the sstr2 and sstr5 somatostatin receptors.