The Authors describe a reversed-phase HPLC method for the separation of the six peptides which constitute the antitumoral drug Peptichemio (PTC). They also present some preliminary investigations concerning the in vitro biopharmacokinetics of this drug. Differences in selectivity and kinetics of peptides uptake have been investigated using human peripheral blood lymphocytes (PBL) and a human neuroblastoma derived cell line (SK-N-SH). Results will be discussed along with their clinical and pharmacological research implications.