Dendritic polymers for dermal drug delivery

Dendrimers, or chemistry’s snowflake, are complex polymers that have the potential for many drug delivery applications. Starting with a singular atom at its core, dendrimers are formed through the connection of layer upon layer of additional functional groups until a spherical macromolecule is created. Polymers are materials that are made of many repeating units, also known as monomers, that are linked together to form long chains, which can be linear or, in this case, branched and spherical. 

Although these macromolecules are difficult to synthesize, researchers find them appealing for drug delivery because of some of their unique properties including water solubility, internal cavities, and uniform size. Since they are synthesized from the inner layer out, it gives scientists the ability to customize the surface functionality of the molecule. Often this entails a hydrophilic (water-soluble) outer layer and hydrophobic (water repellent) center. With these properties, scientists are investigating its application for oral drug delivery, but more notably, transdermal (through the skin) drug delivery provides a new research avenue. 

For most medications, oral drugs provide easy administration, but sometimes patients are unable to take drugs orally because of negative side effects or because some molecules are destroyed when exposed to the gut environment. Thus, transdermal drug delivery provides a promising alternative, since the skin is a relatively permeable surface. This will be especially helpful for many of the new hydrophobic drugs that have low water solubility. Instead, these drugs can be fitted into the internal cavity of a dendrimer and passively sent through the skin and into cells because of its outer hydrophilic nature. 

The extent of using dendrimers for drug delivery is still currently being researched. Possible medication applications include anticancer, antiviral, and nonsteroidal anti-inflammatory drugs. However, they are highly difficult and expensive to make, so before these can be mass implemented, chemists will need to continue to reduce the cost of these polymeric drug delivery capsules.

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