Dendrimers have been used to actively or passively target a drug to particular destinations in the body.
There are two mechanisms that may be advantageously employed to control the destination of drugs when attached to a dendrimer.
Active Targeting – Adding a suitable targeting molecule to the construct, such as an antibody, allows the dendrimer to carry a payload to a target receptor. In the image this is achieved for a payload of gadolinium, allowing visualization in an MRI scanner. The payload could equally have been a small molecule drug however.
Left: By associating a dendrimer with a targeting group (e.g. an antibody) multiple “payload” molecules can be delivered to a molecular target. Right: Here the antibody fragment targets certain activated platelets, and the payload is successfully delivered to a blood clot. In a control study without the correct antibody no such delivery was achieved, showing that the targeting in the image above was specific in nature (work conducted in collaboration with the Baker IDI Heart and Diabetes Institute)
Passive Targeting – Even in the absence of any targeting group, tailoring the size and physico-chemical properties of the dendrimer can achieve preferential accumulation in target tissues or organs. This is particularly of interest in the area of cancer treatments.