New microneedle drug monitoring system tests drug levels in blood painlessly

A newly-developed microneedle drug monitoring system would soon make painful blood draws history.

Created by researchers at the University of British Columbia and the Paul Scherrer Institut (PSI) in Switzerland, the new technology comprises a small, thin patch that is pressed against a patient's arm during medical treatment to measure drugs in their bloodstream painlessly without drawing any blood.

The tiny needle-like projection, less-than half a milimetre long, looks like a hollow cone and does not pierce the skin like a standard hypodermic needle.

Microneedles puncture the outer layer of skin, which acts as a protective shield, but leave the next layers of epidermis and the dermis, which house nerves, blood vessels and active immune cells intact.

The microneedle developed by Ranamukhaarachchi and colleagues monitors the antibiotic vancomycin, used in the treatment of serious infections.

Vancomycin is administered through an intravenous line. Patients taking the antibiotic undergo three to four blood draws per day and need to be closely monitored as vancomycin can cause life-threatening toxic side effects.

The researchers found that they could use the fluid found just below the outer layer of skin, instead of blood, to monitor levels of vancomycin in the bloodstream.

 The microneedle collects less than a millionth of a millilitre of fluid and the reaction which occurs inside of the microneedle is detected through an optical sensor to allow researchers to quickly and easily determine the drug levels.

''This is probably one of the smallest probe volumes ever recorded for a medically relevant analysis,'' said Urs Hafeli, an associate professor in UBC's faculty of pharmaceutical sciences in a press release.

''Many groups are researching microneedle technology for painless vaccines and drug delivery. Using them to painlessly monitor drugs is a new idea,'' said Ranamukhaarachchi.