Patent ID: 7052704

Claim:
A method for prolonging blood and tissue retention of a sulfhydrylgroup containing compound selected from the group consisting of peptides, proteins and oligonucleotides into mammalian cells, said method comprising: forming from the sulfhydryl-containing compound a compound of general formula VI in which P is selected from the group consisting of peptides, proteins and oligonucleotides; R 1 is hydrogen, lower alkyl or aryl; R 2 is selected from the group consisting of a lipid, —CH 2 CH 2 CH(NH 2 )CO 2 H and —CH 2 CH 2 CH(NHCO-lipid)CO-lipid; and R 3 is —OH, a lipid or an amino acid chain comprising one or 2 amino acids and terminating in —CO 2 H or —COR 2 ; and administering the compound of general formula VI to the cells; wherein said lipid is a hydrophobic substituent consisting of 4 to 26 carbon atoms and said lipid together with the attached carbonyl is a fatty acid acyl group.