As clearly demonstrated by the DCCT, blood glucose monitoring is a critical element in the maintenance of normal blood glucose levels. Cygnus Therapeutic Corporation in Redwood City, California is working on a new non-invasive glucose monitoring system that could dramatically change the way people with diabetes monitor their glucose levels. Unlike the current procedure, which measures the level of glucose in the blood based on blood samples drawn from the fingertips, the new system is non-invasive, and utilizes interstitial fluid rather than blood.
In a process called “reverse iontophoresis,” a steady electrical current is used to extract interstitial fluid (the fluid that bathes the cells of the body) from the skin. Iontophoresis has been used for years to deliver drugs into the skin by enlarging the pores to allow large molecules (found in drugs) to enter. Reverse iontophoresis simply turns the process around, enlarging the pores to allow interstitial fluid to exit. This procedure was initially discovered by researchers at U.C.S.F. Medical School. Cygnus invested in the patent for it and is now applying it for use as a substitute to blood glucose monitoring.
Thus far, Cygnus has conducted initial testing on both animals and non-diabetic subjects with positive results. The next phase of testing, expected to commence early in 1994, will be carried out on people with diabetes. This testing will attempt to determine the accuracy of glucose measurement from interstitial fluid as compared to blood.
If the next phase of testing proves interstitial fluid to be a reliable, accurate measurement of glucose, Cygnus will begin its effort to make the process “user-friendly.” The current blueprint for the product includes two components: a credit card sized “patch” that adheres to the skin; and, an equally miniaturized “power pack” for reading test results. As it is currently envisioned, the patch would remain on the skin continuously for up to 24 hours, to be replaced by a new patch each day, while the power pack would provide the “hardware” necessary to interpret the results of the chemical process. Together, the two components would allow the user to monitor the level of glucose in the interstitial fluid, both continuously and non-invasively.
Although still in the early phases of development, this research offers potential relief from the sore, callused fingertips so many of us live with as a necessary by-product of blood glucose testing, as well as the possibility of having access to continuous test results.