Tween 80 is also named polysorbate 80. The polysorbates are amphipathic, nonionic surfactants composed of fatty acid esters of polyoxyethylene sorbitan. The oleic acid-containing component of polysorbate 80 is 58% of its total. The remaining fatty acids are a mixture of both saturated and unsaturated fatty acids with caproic, caprylic, capric, and lauric acids being present only in polysorbate 20 with all other fatty acids esters present in both polysorbate 20 and 80 solutions. The structures shown here are those of the chemically homogenous polysorbates. Both Tween 20 and Tween 80 polysorbates have a common backbone and the only difference between the structures of the fatty acid side chains. The hydrocarbon chains provide the hydrophobic nature of the polysorbates while the hydrophilic nature is provided by the ethylene oxide subunits. The common backbone structure is a sorbitan ring with ethylene oxide polymers attached at three different hydroxyl positions. While the number of repeats ethylene oxide subunits varies at each position their total number (w+x+y+z) equals 20 and is constant for each polysorbate. The fatty acid moieties are attached through an ester linkage to the ethylene oxide-oxygen at the z position. The laurate moiety of polysorbate 20 is a straight-chain hydrocarbon structure and the oleate moiety of polysorbate 80 contains a double-bond forming a kink in the hydrocarbon chain.
Fig. 1 Chemical structure of polysorbates 80. (Kerwin, 2008)
Surface-active agents, or surfactants, are often added to protein solutions to prevent physical damage during purification, filtration, transportation, freeze-drying, spray drying, storage, and delivery. Human serum albumin (HSA) was initially used in several protein formulations as a stabilizer to prevent surface adsorption. Recent concerns though about the presence of infectious agents (e.g., viruses, prions) in blood products has prompted many regulatory agencies to no longer allow its use forcing the exploration of other options. Towards that end polysorbates, nonionic surfactants, are increasingly being used as replacements for HSA. The polysorbates are both biocompatible and excellent stabilizers against surface adsorption.
As a professional mRNA delivery services provider and researcher, Creative Biolabs provides Tween 80 and its related products to help global clients with mRNA delivery research.
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