Commonly used ligands in drug delivery.
|Sl. no.||Name of the ligand||Definition||Characteristics|
|(1)||Sugar||Any of a class of sweet, soluble, crystalline carbohydrates, white when pure||The specificity of carbohydrate-protein interactions is much larger than that of many other ligand-binding systems, through its great ability to undergo site-specific modification. Use of carbohydrate ligands to target protein receptors at sites of localization, termed “glycotargeting,” exploits the highly specific interactions of endogenous lectins with carbohydrates|
|(2)||Folic acid||A water-soluble vitamin, yellowish-orange, (C19 H19 N7 O6) belonging to the B-complex group of vitamins||Employed as a targeting moiety for anticancer drugs through covalent conjugation to drugs; the folate receptor-α is overexpressed in several human tumors, including ovarian, lung, brain, head and neck, and breast tumors|
|(3)||Peptide||Natural or synthetic, short polymer chain compound, containing two or more amino acids linked by the carboxyl group of one amino acid to the amino group of another||EGF-R peptide ligand (D4: Leu-Ala-Arg-Leu-Leu-Thr) is conjugated with a polyethylene glycol (PEG) lipid, and the lipid moiety of the peptide-PEG-lipid conjugate is inserted into liposome membranes by a postmodification process. D4 peptide-conjugated liposomes bind to and enter cells by endocytosis specifically and efficiently in vitro in a process apparently mediated by EGF-R high-expressing cancer cells (H1299) |
|(4)||Antibody||An immunoglobulin, a specialized immune protein, generally found in the blood that detects and destroys invaders, like bacteria, and so forth; produced because of the introduction of an antigen into the body||anti-CEA (Carcinoembryonic Antigen) half-antibody conjugated lipid-polymer hybrid nanoparticles show enhanced cancer killing effect compared to the corresponding nontargeted nanoparticles |