Written by Thomas Pollard.

Current drug dosing strategies are too rigid, with doses fixed regardless of the individual. This can lead to under-dosing and toxic side effects depending on the person. This problem is heightened in narrow therapeutic index drugs, where the balance between a drug’s effective and toxic concentrations is tenuous.

One way to improve dosing of narrow therapeutic index drugs is through therapeutic drug monitoring, where the concentration of the drug in a bodily fluid is measured to determine if the current dosing strategy is suitable. In a recent review, we summarise how this can be achieved using electrochemical biosensors: https://doi.org/10.1016/j.drudis.2020.10.021.

Electrochemical biosensors measure drug concentrations through changes in electrical properties. Electrochemical biosensors are already used in healthcare, with the most common example being glucose detection.

A few examples of technologies from the literature stand out. One of these is microneedles, which could allow for drug measurements to be made in interstitial fluid. Another example of how therapeutic drug monitoring could be of use is in closed loop monitoring, where the dose a patient receives is continuously adjusted in response to their measured drug concentration. Molecularly imprinted polymers, a synthetic method for selectively binding the drug, is also a possible method, as are multi-material biorecognition layers.

Electrochemical biosensors have the potential to be an important technology in the future of healthcare, but their effectiveness and commercialisation remains to be seen. Hopefully, with more research, this future can be achieved.