Dendrimersomes for Ingredient Delivery

By: Katie Schaefer, C&T magazine

Posted: June 29, 2010, from the July 2010 issue of Cosmetics & Toiletries.

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Dendrimersomes
Dendrimers are polymers having every monomer unit branched. They have three main components: a center core, a dendritic or branched interior, and exterior end groups. They are perfectly branched, and have a highly functional surface and an open core.¹

In Roman mythology, Janus was the god of gates and doorways and was depicted as having two different faces. Similarly, Janus dendrimers contain two completely dissimilar structures: hydrophilic and hydrophobic dendrons, which together create amphiphilic Janus dendrimers in morphologies such as tubular vesicles, helical ribbons and cubosomes. “We made a water-soluble/water-insoluble molecule—an amphiphilic molecule that behaves like an amphiphilic block polymer or an amphiphilic phospholipid,” said Percec. This dendrimersome self-assembles vesicles in combination with water.

Like the other vesicles, two different materials or drugs can be incorporated into a dendrimersome. However, a dendrimersome can go one step further. “In a vesicle, you can incorporate two different drugs: one that is water-soluble, which goes into the middle of the molecule, and one that is water-insoluble [i.e., hydrophobic], which you incorporate [within the vesicle but around the outside of the water-soluble drug].” In addition to two materials, Percec noted that a third, fourth or fifth one may be added by functionalizing the periphery of the Janus dendrimer. More than two raw materials or actives cannot be easily incorporated into a liposome or polymersome, according to Percec, since they only have one chain end. He explained, “Janus dendrimers have up to 10–20 chain ends in each molecule and by functionalizing them, we do not change their self-assembly behavior.”

Cosmetic Effects
Dendrimersomes can impact cosmetics in that, according to Percec, besides their benefits in dispersion, biocompatibility and stability, dendrimersomes can be offered in a number of morphologies depending upon application. In addition, the methods used to produce these morphologies are reportedly simple, inexpensive chemistries. Percec further adds that dendrimersomes may allow formulators to incorporate a number of raw materials into a formulation.

“In addition to one or two ingredients, [the formulator] may want to functionalize or incorporate dyes on the periphery to provide a color to cosmetics,” said Percec. The research team has not yet examined dendrimersomes in cosmetic formulas, but it has plans to do so soon. Although there is still some research yet to be completed and regulatory approvals to obtain, Percec is optimistic that the technology will be commercially available soon.