Glucose Monitoring by Reverse Iontophoresis

Glucose can be extracted through intact skin upon application of a low-level electrical current by electroosmotic flow (a process called “reverse iontophoresis”). Recently we have combined iontophoretic extraction with an in situ glucose sensor in a device called the Gluco Watch® biographer. Clinical results with this device show close tracking of blood glucose over a range of 40 to 400 mg/dL (2.2 to 22.2 mmol/L) for up to 12 hours using a single blood glucose value as calibration. The biographer readings lag behind blood glucose values by an average of 18 minutes. An analysis of data from 92 diabetic subjects in a controlled clinical setting shows a linear relationship (r=0.88) between GlucoWatch biographer readings and blood glucose. The mean absolute difference between the two measurements was 15.6% and more than 96% of the data fell in the (A+B) regions of the Clarke error grid. Similar results have been obtained from subjects using the GlucoWatch biographer in an uncontrolled home environment. The automatic, frequent, and non-invasive measurements obtained with the GlucoWatch biographer provide substantially more information about glucose levels than the current finger-stick methods. This information can be used for improved decisions about all aspects of diabetes management.