MAL-dPEG®₂₄-amido-dPEG®₂₄-DSPE

MAL-dPEG®24-amido-dPEG®24-DSPE, product number 11093, is designed for development of liposomes and micelles. The polyethylene glycol (PEG) unit on the molecule is a single molecular weight discrete PEG (dPEG®). The dPEG® terminus is functionalized with a maleimidopropyl group. The lipophilic tail of the molecule contains 1, 2-Distearoyl-sn-glycero-3-phosphoethanolamine (DSPE) for insertion into a liposomal membrane.

Liposomes and micelles are widely used for payload delivery, including peptides and small molecule drugs, and in imaging applications. Without PEG, liposomes and micelles clear quickly from the blood via the reticuloendothelial system (RES). A sufficiently dense coating of PEG creates a hydrophilic, flexible, steric barrier around the PEGylated liposomes and micelles, thus preventing opsonin proteins from binding to the liposomal/micellar surface (opsonization). Consequently, liposomes and micelles circulate longer in the bloodstream, which therefore results in lower dosing requirements.

Phosphatidylethanolamine (PE) conjugated to PEG is frequently used for PEGylated liposomes. Of the PE-PEG conjugates, DSPE-PEG has been most studied. Several studies have shown that the optimal PEG molecular weight for a DSPE-PEG conjugate is approximately 2,000 Daltons. This mass of PEG in the conjugate appears to provide the optimum balance between preventing opsonization of the liposome and maintaining effective cellular uptake of PEGylated liposomes. Larger molecular weight PEGs inhibit cellular uptake without providing any additional protection from opsonization.

Unlike traditional, disperse polymer PEGs (Đ > 1), our dPEG® products are designed as single molecular weight products with discrete chain lengths (Đ = 1). This simplifies product analysis because there is no intractable mixture of chain lengths and molecular weights as is the nature of polymeric PEGs. Simplified product analysis saves time and money for cost conscious companies seeking to develop new delivery technologies for diagnostic, therapeutic, or imaging applications.

The maleimide functional group at the terminus of MAL-dPEG®24-amido-dPEG®24-DSPE can react with a sulfhydryl group to conjugate a drug or small molecule on the surface of the liposome or micelle. Furthermore, at least one study suggests that a small amount of surface modification with maleimide enhances cellular uptake of liposomes or micelles and consequent drug delivery by inducing thiol-mediated membrane trafficking.

If you need bulk product in a larger package size than our standard sizes, please contact us for a quote. Our commercial capabilities permit us to manufacture this product at any scale that you need.

Application References:

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Che, J.; Okeke, C. I.; Zhong-Bo, H. and Xu, J. DSPE-PEG: A Distinctive Component in Drug Delivery System. Curr Pharm Design, 2015, 21(12), 1598-1605.
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